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| author | wolfbeast <mcwerewolf@gmail.com> | 2018-05-14 10:50:01 +0200 |
|---|---|---|
| committer | wolfbeast <mcwerewolf@gmail.com> | 2018-05-14 10:50:01 +0200 |
| commit | e9dd029f5d00590e1a53e63b0ab805110a10b54c (patch) | |
| tree | 1126ca5dda925a62be3dc12c99c90e953d08afcf /memory/jemalloc/src/doc/jemalloc.xml.in | |
| parent | 9d6a7ae25d7f5da855a8f8df884de483b4e2a538 (diff) | |
| parent | 36b8fd734f590eb726ca2e50f8d1ff9cc968b8e1 (diff) | |
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Merge branch 'master' into Basilisk-release
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| -rw-r--r-- | memory/jemalloc/src/doc/jemalloc.xml.in | 2966 |
1 files changed, 0 insertions, 2966 deletions
diff --git a/memory/jemalloc/src/doc/jemalloc.xml.in b/memory/jemalloc/src/doc/jemalloc.xml.in deleted file mode 100644 index 3d2e721d3..000000000 --- a/memory/jemalloc/src/doc/jemalloc.xml.in +++ /dev/null @@ -1,2966 +0,0 @@ -<?xml version='1.0' encoding='UTF-8'?> -<?xml-stylesheet type="text/xsl" - href="http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"?> -<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" - "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [ -]> - -<refentry> - <refentryinfo> - <title>User Manual</title> - <productname>jemalloc</productname> - <releaseinfo role="version">@jemalloc_version@</releaseinfo> - <authorgroup> - <author> - <firstname>Jason</firstname> - <surname>Evans</surname> - <personblurb>Author</personblurb> - </author> - </authorgroup> - </refentryinfo> - <refmeta> - <refentrytitle>JEMALLOC</refentrytitle> - <manvolnum>3</manvolnum> - </refmeta> - <refnamediv> - <refdescriptor>jemalloc</refdescriptor> - <refname>jemalloc</refname> - <!-- Each refname causes a man page file to be created. Only if this were - the system malloc(3) implementation would these files be appropriate. - <refname>malloc</refname> - <refname>calloc</refname> - <refname>posix_memalign</refname> - <refname>aligned_alloc</refname> - <refname>realloc</refname> - <refname>free</refname> - <refname>mallocx</refname> - <refname>rallocx</refname> - <refname>xallocx</refname> - <refname>sallocx</refname> - <refname>dallocx</refname> - <refname>sdallocx</refname> - <refname>nallocx</refname> - <refname>mallctl</refname> - <refname>mallctlnametomib</refname> - <refname>mallctlbymib</refname> - <refname>malloc_stats_print</refname> - <refname>malloc_usable_size</refname> - --> - <refpurpose>general purpose memory allocation functions</refpurpose> - </refnamediv> - <refsect1 id="library"> - <title>LIBRARY</title> - <para>This manual describes jemalloc @jemalloc_version@. More information - can be found at the <ulink - url="http://jemalloc.net/">jemalloc website</ulink>.</para> - </refsect1> - <refsynopsisdiv> - <title>SYNOPSIS</title> - <funcsynopsis> - <funcsynopsisinfo>#include <<filename class="headerfile">jemalloc/jemalloc.h</filename>></funcsynopsisinfo> - <refsect2> - <title>Standard API</title> - <funcprototype> - <funcdef>void *<function>malloc</function></funcdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void *<function>calloc</function></funcdef> - <paramdef>size_t <parameter>number</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>int <function>posix_memalign</function></funcdef> - <paramdef>void **<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>alignment</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void *<function>aligned_alloc</function></funcdef> - <paramdef>size_t <parameter>alignment</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void *<function>realloc</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>free</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - </funcprototype> - </refsect2> - <refsect2> - <title>Non-standard API</title> - <funcprototype> - <funcdef>void *<function>mallocx</function></funcdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void *<function>rallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>size_t <function>xallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>extra</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>size_t <function>sallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>dallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>sdallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>size_t <function>nallocx</function></funcdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>int <function>mallctl</function></funcdef> - <paramdef>const char *<parameter>name</parameter></paramdef> - <paramdef>void *<parameter>oldp</parameter></paramdef> - <paramdef>size_t *<parameter>oldlenp</parameter></paramdef> - <paramdef>void *<parameter>newp</parameter></paramdef> - <paramdef>size_t <parameter>newlen</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>int <function>mallctlnametomib</function></funcdef> - <paramdef>const char *<parameter>name</parameter></paramdef> - <paramdef>size_t *<parameter>mibp</parameter></paramdef> - <paramdef>size_t *<parameter>miblenp</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>int <function>mallctlbymib</function></funcdef> - <paramdef>const size_t *<parameter>mib</parameter></paramdef> - <paramdef>size_t <parameter>miblen</parameter></paramdef> - <paramdef>void *<parameter>oldp</parameter></paramdef> - <paramdef>size_t *<parameter>oldlenp</parameter></paramdef> - <paramdef>void *<parameter>newp</parameter></paramdef> - <paramdef>size_t <parameter>newlen</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>malloc_stats_print</function></funcdef> - <paramdef>void <parameter>(*write_cb)</parameter> - <funcparams>void *, const char *</funcparams> - </paramdef> - <paramdef>void *<parameter>cbopaque</parameter></paramdef> - <paramdef>const char *<parameter>opts</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>size_t <function>malloc_usable_size</function></funcdef> - <paramdef>const void *<parameter>ptr</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>(*malloc_message)</function></funcdef> - <paramdef>void *<parameter>cbopaque</parameter></paramdef> - <paramdef>const char *<parameter>s</parameter></paramdef> - </funcprototype> - <para><type>const char *</type><varname>malloc_conf</varname>;</para> - </refsect2> - </funcsynopsis> - </refsynopsisdiv> - <refsect1 id="description"> - <title>DESCRIPTION</title> - <refsect2> - <title>Standard API</title> - - <para>The <function>malloc()</function> function allocates - <parameter>size</parameter> bytes of uninitialized memory. The allocated - space is suitably aligned (after possible pointer coercion) for storage - of any type of object.</para> - - <para>The <function>calloc()</function> function allocates - space for <parameter>number</parameter> objects, each - <parameter>size</parameter> bytes in length. The result is identical to - calling <function>malloc()</function> with an argument of - <parameter>number</parameter> * <parameter>size</parameter>, with the - exception that the allocated memory is explicitly initialized to zero - bytes.</para> - - <para>The <function>posix_memalign()</function> function - allocates <parameter>size</parameter> bytes of memory such that the - allocation's base address is a multiple of - <parameter>alignment</parameter>, and returns the allocation in the value - pointed to by <parameter>ptr</parameter>. The requested - <parameter>alignment</parameter> must be a power of 2 at least as large as - <code language="C">sizeof(<type>void *</type>)</code>.</para> - - <para>The <function>aligned_alloc()</function> function - allocates <parameter>size</parameter> bytes of memory such that the - allocation's base address is a multiple of - <parameter>alignment</parameter>. The requested - <parameter>alignment</parameter> must be a power of 2. Behavior is - undefined if <parameter>size</parameter> is not an integral multiple of - <parameter>alignment</parameter>.</para> - - <para>The <function>realloc()</function> function changes the - size of the previously allocated memory referenced by - <parameter>ptr</parameter> to <parameter>size</parameter> bytes. The - contents of the memory are unchanged up to the lesser of the new and old - sizes. If the new size is larger, the contents of the newly allocated - portion of the memory are undefined. Upon success, the memory referenced - by <parameter>ptr</parameter> is freed and a pointer to the newly - allocated memory is returned. Note that - <function>realloc()</function> may move the memory allocation, - resulting in a different return value than <parameter>ptr</parameter>. - If <parameter>ptr</parameter> is <constant>NULL</constant>, the - <function>realloc()</function> function behaves identically to - <function>malloc()</function> for the specified size.</para> - - <para>The <function>free()</function> function causes the - allocated memory referenced by <parameter>ptr</parameter> to be made - available for future allocations. If <parameter>ptr</parameter> is - <constant>NULL</constant>, no action occurs.</para> - </refsect2> - <refsect2> - <title>Non-standard API</title> - <para>The <function>mallocx()</function>, - <function>rallocx()</function>, - <function>xallocx()</function>, - <function>sallocx()</function>, - <function>dallocx()</function>, - <function>sdallocx()</function>, and - <function>nallocx()</function> functions all have a - <parameter>flags</parameter> argument that can be used to specify - options. The functions only check the options that are contextually - relevant. Use bitwise or (<code language="C">|</code>) operations to - specify one or more of the following: - <variablelist> - <varlistentry id="MALLOCX_LG_ALIGN"> - <term><constant>MALLOCX_LG_ALIGN(<parameter>la</parameter>) - </constant></term> - - <listitem><para>Align the memory allocation to start at an address - that is a multiple of <code language="C">(1 << - <parameter>la</parameter>)</code>. This macro does not validate - that <parameter>la</parameter> is within the valid - range.</para></listitem> - </varlistentry> - <varlistentry id="MALLOCX_ALIGN"> - <term><constant>MALLOCX_ALIGN(<parameter>a</parameter>) - </constant></term> - - <listitem><para>Align the memory allocation to start at an address - that is a multiple of <parameter>a</parameter>, where - <parameter>a</parameter> is a power of two. This macro does not - validate that <parameter>a</parameter> is a power of 2. - </para></listitem> - </varlistentry> - <varlistentry id="MALLOCX_ZERO"> - <term><constant>MALLOCX_ZERO</constant></term> - - <listitem><para>Initialize newly allocated memory to contain zero - bytes. In the growing reallocation case, the real size prior to - reallocation defines the boundary between untouched bytes and those - that are initialized to contain zero bytes. If this macro is - absent, newly allocated memory is uninitialized.</para></listitem> - </varlistentry> - <varlistentry id="MALLOCX_TCACHE"> - <term><constant>MALLOCX_TCACHE(<parameter>tc</parameter>) - </constant></term> - - <listitem><para>Use the thread-specific cache (tcache) specified by - the identifier <parameter>tc</parameter>, which must have been - acquired via the <link - linkend="tcache.create"><mallctl>tcache.create</mallctl></link> - mallctl. This macro does not validate that - <parameter>tc</parameter> specifies a valid - identifier.</para></listitem> - </varlistentry> - <varlistentry id="MALLOC_TCACHE_NONE"> - <term><constant>MALLOCX_TCACHE_NONE</constant></term> - - <listitem><para>Do not use a thread-specific cache (tcache). Unless - <constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant> or - <constant>MALLOCX_TCACHE_NONE</constant> is specified, an - automatically managed tcache will be used under many circumstances. - This macro cannot be used in the same <parameter>flags</parameter> - argument as - <constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant>.</para></listitem> - </varlistentry> - <varlistentry id="MALLOCX_ARENA"> - <term><constant>MALLOCX_ARENA(<parameter>a</parameter>) - </constant></term> - - <listitem><para>Use the arena specified by the index - <parameter>a</parameter>. This macro has no effect for regions that - were allocated via an arena other than the one specified. This - macro does not validate that <parameter>a</parameter> specifies an - arena index in the valid range.</para></listitem> - </varlistentry> - </variablelist> - </para> - - <para>The <function>mallocx()</function> function allocates at - least <parameter>size</parameter> bytes of memory, and returns a pointer - to the base address of the allocation. Behavior is undefined if - <parameter>size</parameter> is <constant>0</constant>.</para> - - <para>The <function>rallocx()</function> function resizes the - allocation at <parameter>ptr</parameter> to be at least - <parameter>size</parameter> bytes, and returns a pointer to the base - address of the resulting allocation, which may or may not have moved from - its original location. Behavior is undefined if - <parameter>size</parameter> is <constant>0</constant>.</para> - - <para>The <function>xallocx()</function> function resizes the - allocation at <parameter>ptr</parameter> in place to be at least - <parameter>size</parameter> bytes, and returns the real size of the - allocation. If <parameter>extra</parameter> is non-zero, an attempt is - made to resize the allocation to be at least <code - language="C">(<parameter>size</parameter> + - <parameter>extra</parameter>)</code> bytes, though inability to allocate - the extra byte(s) will not by itself result in failure to resize. - Behavior is undefined if <parameter>size</parameter> is - <constant>0</constant>, or if <code - language="C">(<parameter>size</parameter> + <parameter>extra</parameter> - > <constant>SIZE_T_MAX</constant>)</code>.</para> - - <para>The <function>sallocx()</function> function returns the - real size of the allocation at <parameter>ptr</parameter>.</para> - - <para>The <function>dallocx()</function> function causes the - memory referenced by <parameter>ptr</parameter> to be made available for - future allocations.</para> - - <para>The <function>sdallocx()</function> function is an - extension of <function>dallocx()</function> with a - <parameter>size</parameter> parameter to allow the caller to pass in the - allocation size as an optimization. The minimum valid input size is the - original requested size of the allocation, and the maximum valid input - size is the corresponding value returned by - <function>nallocx()</function> or - <function>sallocx()</function>.</para> - - <para>The <function>nallocx()</function> function allocates no - memory, but it performs the same size computation as the - <function>mallocx()</function> function, and returns the real - size of the allocation that would result from the equivalent - <function>mallocx()</function> function call, or - <constant>0</constant> if the inputs exceed the maximum supported size - class and/or alignment. Behavior is undefined if - <parameter>size</parameter> is <constant>0</constant>.</para> - - <para>The <function>mallctl()</function> function provides a - general interface for introspecting the memory allocator, as well as - setting modifiable parameters and triggering actions. The - period-separated <parameter>name</parameter> argument specifies a - location in a tree-structured namespace; see the <xref - linkend="mallctl_namespace" xrefstyle="template:%t"/> section for - documentation on the tree contents. To read a value, pass a pointer via - <parameter>oldp</parameter> to adequate space to contain the value, and a - pointer to its length via <parameter>oldlenp</parameter>; otherwise pass - <constant>NULL</constant> and <constant>NULL</constant>. Similarly, to - write a value, pass a pointer to the value via - <parameter>newp</parameter>, and its length via - <parameter>newlen</parameter>; otherwise pass <constant>NULL</constant> - and <constant>0</constant>.</para> - - <para>The <function>mallctlnametomib()</function> function - provides a way to avoid repeated name lookups for applications that - repeatedly query the same portion of the namespace, by translating a name - to a <quote>Management Information Base</quote> (MIB) that can be passed - repeatedly to <function>mallctlbymib()</function>. Upon - successful return from <function>mallctlnametomib()</function>, - <parameter>mibp</parameter> contains an array of - <parameter>*miblenp</parameter> integers, where - <parameter>*miblenp</parameter> is the lesser of the number of components - in <parameter>name</parameter> and the input value of - <parameter>*miblenp</parameter>. Thus it is possible to pass a - <parameter>*miblenp</parameter> that is smaller than the number of - period-separated name components, which results in a partial MIB that can - be used as the basis for constructing a complete MIB. For name - components that are integers (e.g. the 2 in - <link - linkend="arenas.bin.i.size"><mallctl>arenas.bin.2.size</mallctl></link>), - the corresponding MIB component will always be that integer. Therefore, - it is legitimate to construct code like the following: <programlisting - language="C"><![CDATA[ -unsigned nbins, i; -size_t mib[4]; -size_t len, miblen; - -len = sizeof(nbins); -mallctl("arenas.nbins", &nbins, &len, NULL, 0); - -miblen = 4; -mallctlnametomib("arenas.bin.0.size", mib, &miblen); -for (i = 0; i < nbins; i++) { - size_t bin_size; - - mib[2] = i; - len = sizeof(bin_size); - mallctlbymib(mib, miblen, &bin_size, &len, NULL, 0); - /* Do something with bin_size... */ -}]]></programlisting></para> - - <para>The <function>malloc_stats_print()</function> function writes - summary statistics via the <parameter>write_cb</parameter> callback - function pointer and <parameter>cbopaque</parameter> data passed to - <parameter>write_cb</parameter>, or <function>malloc_message()</function> - if <parameter>write_cb</parameter> is <constant>NULL</constant>. The - statistics are presented in human-readable form unless <quote>J</quote> is - specified as a character within the <parameter>opts</parameter> string, in - which case the statistics are presented in <ulink - url="http://www.json.org/">JSON format</ulink>. This function can be - called repeatedly. General information that never changes during - execution can be omitted by specifying <quote>g</quote> as a character - within the <parameter>opts</parameter> string. Note that - <function>malloc_message()</function> uses the - <function>mallctl*()</function> functions internally, so inconsistent - statistics can be reported if multiple threads use these functions - simultaneously. If <option>--enable-stats</option> is specified during - configuration, <quote>m</quote> and <quote>a</quote> can be specified to - omit merged arena and per arena statistics, respectively; - <quote>b</quote>, <quote>l</quote>, and <quote>h</quote> can be specified - to omit per size class statistics for bins, large objects, and huge - objects, respectively. Unrecognized characters are silently ignored. - Note that thread caching may prevent some statistics from being completely - up to date, since extra locking would be required to merge counters that - track thread cache operations.</para> - - <para>The <function>malloc_usable_size()</function> function - returns the usable size of the allocation pointed to by - <parameter>ptr</parameter>. The return value may be larger than the size - that was requested during allocation. The - <function>malloc_usable_size()</function> function is not a - mechanism for in-place <function>realloc()</function>; rather - it is provided solely as a tool for introspection purposes. Any - discrepancy between the requested allocation size and the size reported - by <function>malloc_usable_size()</function> should not be - depended on, since such behavior is entirely implementation-dependent. - </para> - </refsect2> - </refsect1> - <refsect1 id="tuning"> - <title>TUNING</title> - <para>Once, when the first call is made to one of the memory allocation - routines, the allocator initializes its internals based in part on various - options that can be specified at compile- or run-time.</para> - - <para>The string specified via <option>--with-malloc-conf</option>, the - string pointed to by the global variable <varname>malloc_conf</varname>, the - <quote>name</quote> of the file referenced by the symbolic link named - <filename class="symlink">/etc/malloc.conf</filename>, and the value of the - environment variable <envar>MALLOC_CONF</envar>, will be interpreted, in - that order, from left to right as options. Note that - <varname>malloc_conf</varname> may be read before - <function>main()</function> is entered, so the declaration of - <varname>malloc_conf</varname> should specify an initializer that contains - the final value to be read by jemalloc. <option>--with-malloc-conf</option> - and <varname>malloc_conf</varname> are compile-time mechanisms, whereas - <filename class="symlink">/etc/malloc.conf</filename> and - <envar>MALLOC_CONF</envar> can be safely set any time prior to program - invocation.</para> - - <para>An options string is a comma-separated list of option:value pairs. - There is one key corresponding to each <link - linkend="opt.abort"><mallctl>opt.*</mallctl></link> mallctl (see the <xref - linkend="mallctl_namespace" xrefstyle="template:%t"/> section for options - documentation). For example, <literal>abort:true,narenas:1</literal> sets - the <link linkend="opt.abort"><mallctl>opt.abort</mallctl></link> and <link - linkend="opt.narenas"><mallctl>opt.narenas</mallctl></link> options. Some - options have boolean values (true/false), others have integer values (base - 8, 10, or 16, depending on prefix), and yet others have raw string - values.</para> - </refsect1> - <refsect1 id="implementation_notes"> - <title>IMPLEMENTATION NOTES</title> - <para>Traditionally, allocators have used - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> to obtain memory, which is - suboptimal for several reasons, including race conditions, increased - fragmentation, and artificial limitations on maximum usable memory. If - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> is supported by the operating - system, this allocator uses both - <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> and - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, in that order of preference; - otherwise only <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> is used.</para> - - <para>This allocator uses multiple arenas in order to reduce lock - contention for threaded programs on multi-processor systems. This works - well with regard to threading scalability, but incurs some costs. There is - a small fixed per-arena overhead, and additionally, arenas manage memory - completely independently of each other, which means a small fixed increase - in overall memory fragmentation. These overheads are not generally an - issue, given the number of arenas normally used. Note that using - substantially more arenas than the default is not likely to improve - performance, mainly due to reduced cache performance. However, it may make - sense to reduce the number of arenas if an application does not make much - use of the allocation functions.</para> - - <para>In addition to multiple arenas, unless - <option>--disable-tcache</option> is specified during configuration, this - allocator supports thread-specific caching for small and large objects, in - order to make it possible to completely avoid synchronization for most - allocation requests. Such caching allows very fast allocation in the - common case, but it increases memory usage and fragmentation, since a - bounded number of objects can remain allocated in each thread cache.</para> - - <para>Memory is conceptually broken into equal-sized chunks, where the chunk - size is a power of two that is greater than the page size. Chunks are - always aligned to multiples of the chunk size. This alignment makes it - possible to find metadata for user objects very quickly. User objects are - broken into three categories according to size: small, large, and huge. - Multiple small and large objects can reside within a single chunk, whereas - huge objects each have one or more chunks backing them. Each chunk that - contains small and/or large objects tracks its contents as runs of - contiguous pages (unused, backing a set of small objects, or backing one - large object). The combination of chunk alignment and chunk page maps makes - it possible to determine all metadata regarding small and large allocations - in constant time.</para> - - <para>Small objects are managed in groups by page runs. Each run maintains - a bitmap to track which regions are in use. Allocation requests that are no - more than half the quantum (8 or 16, depending on architecture) are rounded - up to the nearest power of two that is at least <code - language="C">sizeof(<type>double</type>)</code>. All other object size - classes are multiples of the quantum, spaced such that there are four size - classes for each doubling in size, which limits internal fragmentation to - approximately 20% for all but the smallest size classes. Small size classes - are smaller than four times the page size, large size classes are smaller - than the chunk size (see the <link - linkend="opt.lg_chunk"><mallctl>opt.lg_chunk</mallctl></link> option), and - huge size classes extend from the chunk size up to the largest size class - that does not exceed <constant>PTRDIFF_MAX</constant>.</para> - - <para>Allocations are packed tightly together, which can be an issue for - multi-threaded applications. If you need to assure that allocations do not - suffer from cacheline sharing, round your allocation requests up to the - nearest multiple of the cacheline size, or specify cacheline alignment when - allocating.</para> - - <para>The <function>realloc()</function>, - <function>rallocx()</function>, and - <function>xallocx()</function> functions may resize allocations - without moving them under limited circumstances. Unlike the - <function>*allocx()</function> API, the standard API does not - officially round up the usable size of an allocation to the nearest size - class, so technically it is necessary to call - <function>realloc()</function> to grow e.g. a 9-byte allocation to - 16 bytes, or shrink a 16-byte allocation to 9 bytes. Growth and shrinkage - trivially succeeds in place as long as the pre-size and post-size both round - up to the same size class. No other API guarantees are made regarding - in-place resizing, but the current implementation also tries to resize large - and huge allocations in place, as long as the pre-size and post-size are - both large or both huge. In such cases shrinkage always succeeds for large - size classes, but for huge size classes the chunk allocator must support - splitting (see <link - linkend="arena.i.chunk_hooks"><mallctl>arena.<i>.chunk_hooks</mallctl></link>). - Growth only succeeds if the trailing memory is currently available, and - additionally for huge size classes the chunk allocator must support - merging.</para> - - <para>Assuming 2 MiB chunks, 4 KiB pages, and a 16-byte quantum on a - 64-bit system, the size classes in each category are as shown in <xref - linkend="size_classes" xrefstyle="template:Table %n"/>.</para> - - <table xml:id="size_classes" frame="all"> - <title>Size classes</title> - <tgroup cols="3" colsep="1" rowsep="1"> - <colspec colname="c1" align="left"/> - <colspec colname="c2" align="right"/> - <colspec colname="c3" align="left"/> - <thead> - <row> - <entry>Category</entry> - <entry>Spacing</entry> - <entry>Size</entry> - </row> - </thead> - <tbody> - <row> - <entry morerows="8">Small</entry> - <entry>lg</entry> - <entry>[8]</entry> - </row> - <row> - <entry>16</entry> - <entry>[16, 32, 48, 64, 80, 96, 112, 128]</entry> - </row> - <row> - <entry>32</entry> - <entry>[160, 192, 224, 256]</entry> - </row> - <row> - <entry>64</entry> - <entry>[320, 384, 448, 512]</entry> - </row> - <row> - <entry>128</entry> - <entry>[640, 768, 896, 1024]</entry> - </row> - <row> - <entry>256</entry> - <entry>[1280, 1536, 1792, 2048]</entry> - </row> - <row> - <entry>512</entry> - <entry>[2560, 3072, 3584, 4096]</entry> - </row> - <row> - <entry>1 KiB</entry> - <entry>[5 KiB, 6 KiB, 7 KiB, 8 KiB]</entry> - </row> - <row> - <entry>2 KiB</entry> - <entry>[10 KiB, 12 KiB, 14 KiB]</entry> - </row> - <row> - <entry morerows="7">Large</entry> - <entry>2 KiB</entry> - <entry>[16 KiB]</entry> - </row> - <row> - <entry>4 KiB</entry> - <entry>[20 KiB, 24 KiB, 28 KiB, 32 KiB]</entry> - </row> - <row> - <entry>8 KiB</entry> - <entry>[40 KiB, 48 KiB, 54 KiB, 64 KiB]</entry> - </row> - <row> - <entry>16 KiB</entry> - <entry>[80 KiB, 96 KiB, 112 KiB, 128 KiB]</entry> - </row> - <row> - <entry>32 KiB</entry> - <entry>[160 KiB, 192 KiB, 224 KiB, 256 KiB]</entry> - </row> - <row> - <entry>64 KiB</entry> - <entry>[320 KiB, 384 KiB, 448 KiB, 512 KiB]</entry> - </row> - <row> - <entry>128 KiB</entry> - <entry>[640 KiB, 768 KiB, 896 KiB, 1 MiB]</entry> - </row> - <row> - <entry>256 KiB</entry> - <entry>[1280 KiB, 1536 KiB, 1792 KiB]</entry> - </row> - <row> - <entry morerows="8">Huge</entry> - <entry>256 KiB</entry> - <entry>[2 MiB]</entry> - </row> - <row> - <entry>512 KiB</entry> - <entry>[2560 KiB, 3 MiB, 3584 KiB, 4 MiB]</entry> - </row> - <row> - <entry>1 MiB</entry> - <entry>[5 MiB, 6 MiB, 7 MiB, 8 MiB]</entry> - </row> - <row> - <entry>2 MiB</entry> - <entry>[10 MiB, 12 MiB, 14 MiB, 16 MiB]</entry> - </row> - <row> - <entry>4 MiB</entry> - <entry>[20 MiB, 24 MiB, 28 MiB, 32 MiB]</entry> - </row> - <row> - <entry>8 MiB</entry> - <entry>[40 MiB, 48 MiB, 56 MiB, 64 MiB]</entry> - </row> - <row> - <entry>...</entry> - <entry>...</entry> - </row> - <row> - <entry>512 PiB</entry> - <entry>[2560 PiB, 3 EiB, 3584 PiB, 4 EiB]</entry> - </row> - <row> - <entry>1 EiB</entry> - <entry>[5 EiB, 6 EiB, 7 EiB]</entry> - </row> - </tbody> - </tgroup> - </table> - </refsect1> - <refsect1 id="mallctl_namespace"> - <title>MALLCTL NAMESPACE</title> - <para>The following names are defined in the namespace accessible via the - <function>mallctl*()</function> functions. Value types are - specified in parentheses, their readable/writable statuses are encoded as - <literal>rw</literal>, <literal>r-</literal>, <literal>-w</literal>, or - <literal>--</literal>, and required build configuration flags follow, if - any. A name element encoded as <literal><i></literal> or - <literal><j></literal> indicates an integer component, where the - integer varies from 0 to some upper value that must be determined via - introspection. In the case of <mallctl>stats.arenas.<i>.*</mallctl>, - <literal><i></literal> equal to <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link> can be - used to access the summation of statistics from all arenas. Take special - note of the <link linkend="epoch"><mallctl>epoch</mallctl></link> mallctl, - which controls refreshing of cached dynamic statistics.</para> - - <variablelist> - <varlistentry id="version"> - <term> - <mallctl>version</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Return the jemalloc version string.</para></listitem> - </varlistentry> - - <varlistentry id="epoch"> - <term> - <mallctl>epoch</mallctl> - (<type>uint64_t</type>) - <literal>rw</literal> - </term> - <listitem><para>If a value is passed in, refresh the data from which - the <function>mallctl*()</function> functions report values, - and increment the epoch. Return the current epoch. This is useful for - detecting whether another thread caused a refresh.</para></listitem> - </varlistentry> - - <varlistentry id="config.cache_oblivious"> - <term> - <mallctl>config.cache_oblivious</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-cache-oblivious</option> was specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.debug"> - <term> - <mallctl>config.debug</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-debug</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.fill"> - <term> - <mallctl>config.fill</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-fill</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.lazy_lock"> - <term> - <mallctl>config.lazy_lock</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-lazy-lock</option> was specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.malloc_conf"> - <term> - <mallctl>config.malloc_conf</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Embedded configure-time-specified run-time options - string, empty unless <option>--with-malloc-conf</option> was specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.munmap"> - <term> - <mallctl>config.munmap</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-munmap</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.prof"> - <term> - <mallctl>config.prof</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-prof</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.prof_libgcc"> - <term> - <mallctl>config.prof_libgcc</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--disable-prof-libgcc</option> was not - specified during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.prof_libunwind"> - <term> - <mallctl>config.prof_libunwind</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-prof-libunwind</option> was specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.stats"> - <term> - <mallctl>config.stats</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-stats</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.tcache"> - <term> - <mallctl>config.tcache</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--disable-tcache</option> was not specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.tls"> - <term> - <mallctl>config.tls</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--disable-tls</option> was not specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.utrace"> - <term> - <mallctl>config.utrace</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-utrace</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.valgrind"> - <term> - <mallctl>config.valgrind</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-valgrind</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.xmalloc"> - <term> - <mallctl>config.xmalloc</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-xmalloc</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="opt.abort"> - <term> - <mallctl>opt.abort</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para>Abort-on-warning enabled/disabled. If true, most - warnings are fatal. The process will call - <citerefentry><refentrytitle>abort</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> in these cases. This option is - disabled by default unless <option>--enable-debug</option> is - specified during configuration, in which case it is enabled by default. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.dss"> - <term> - <mallctl>opt.dss</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>dss (<citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>) allocation precedence as - related to <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> allocation. The following - settings are supported if - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> is supported by the operating - system: <quote>disabled</quote>, <quote>primary</quote>, and - <quote>secondary</quote>; otherwise only <quote>disabled</quote> is - supported. The default is <quote>secondary</quote> if - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> is supported by the operating - system; <quote>disabled</quote> otherwise. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_chunk"> - <term> - <mallctl>opt.lg_chunk</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Virtual memory chunk size (log base 2). If a chunk - size outside the supported size range is specified, the size is - silently clipped to the minimum/maximum supported size. The default - chunk size is 2 MiB (2^21). - </para></listitem> - </varlistentry> - - <varlistentry id="opt.narenas"> - <term> - <mallctl>opt.narenas</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum number of arenas to use for automatic - multiplexing of threads and arenas. The default is four times the - number of CPUs, or one if there is a single CPU.</para></listitem> - </varlistentry> - - <varlistentry id="opt.purge"> - <term> - <mallctl>opt.purge</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Purge mode is “ratio” (default) or - “decay”. See <link - linkend="opt.lg_dirty_mult"><mallctl>opt.lg_dirty_mult</mallctl></link> - for details of the ratio mode. See <link - linkend="opt.decay_time"><mallctl>opt.decay_time</mallctl></link> for - details of the decay mode.</para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_dirty_mult"> - <term> - <mallctl>opt.lg_dirty_mult</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Per-arena minimum ratio (log base 2) of active to dirty - pages. Some dirty unused pages may be allowed to accumulate, within - the limit set by the ratio (or one chunk worth of dirty pages, - whichever is greater), before informing the kernel about some of those - pages via <citerefentry><refentrytitle>madvise</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> or a similar system call. This - provides the kernel with sufficient information to recycle dirty pages - if physical memory becomes scarce and the pages remain unused. The - default minimum ratio is 8:1 (2^3:1); an option value of -1 will - disable dirty page purging. See <link - linkend="arenas.lg_dirty_mult"><mallctl>arenas.lg_dirty_mult</mallctl></link> - and <link - linkend="arena.i.lg_dirty_mult"><mallctl>arena.<i>.lg_dirty_mult</mallctl></link> - for related dynamic control options.</para></listitem> - </varlistentry> - - <varlistentry id="opt.decay_time"> - <term> - <mallctl>opt.decay_time</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Approximate time in seconds from the creation of a set - of unused dirty pages until an equivalent set of unused dirty pages is - purged and/or reused. The pages are incrementally purged according to a - sigmoidal decay curve that starts and ends with zero purge rate. A - decay time of 0 causes all unused dirty pages to be purged immediately - upon creation. A decay time of -1 disables purging. The default decay - time is 10 seconds. See <link - linkend="arenas.decay_time"><mallctl>arenas.decay_time</mallctl></link> - and <link - linkend="arena.i.decay_time"><mallctl>arena.<i>.decay_time</mallctl></link> - for related dynamic control options. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.stats_print"> - <term> - <mallctl>opt.stats_print</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para>Enable/disable statistics printing at exit. If - enabled, the <function>malloc_stats_print()</function> - function is called at program exit via an - <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> function. If - <option>--enable-stats</option> is specified during configuration, this - has the potential to cause deadlock for a multi-threaded process that - exits while one or more threads are executing in the memory allocation - functions. Furthermore, <function>atexit()</function> may - allocate memory during application initialization and then deadlock - internally when jemalloc in turn calls - <function>atexit()</function>, so this option is not - universally usable (though the application can register its own - <function>atexit()</function> function with equivalent - functionality). Therefore, this option should only be used with care; - it is primarily intended as a performance tuning aid during application - development. This option is disabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.junk"> - <term> - <mallctl>opt.junk</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - [<option>--enable-fill</option>] - </term> - <listitem><para>Junk filling. If set to <quote>alloc</quote>, each byte - of uninitialized allocated memory will be initialized to - <literal>0xa5</literal>. If set to <quote>free</quote>, all deallocated - memory will be initialized to <literal>0x5a</literal>. If set to - <quote>true</quote>, both allocated and deallocated memory will be - initialized, and if set to <quote>false</quote>, junk filling be - disabled entirely. This is intended for debugging and will impact - performance negatively. This option is <quote>false</quote> by default - unless <option>--enable-debug</option> is specified during - configuration, in which case it is <quote>true</quote> by default unless - running inside <ulink - url="http://valgrind.org/">Valgrind</ulink>.</para></listitem> - </varlistentry> - - <varlistentry id="opt.quarantine"> - <term> - <mallctl>opt.quarantine</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-fill</option>] - </term> - <listitem><para>Per thread quarantine size in bytes. If non-zero, each - thread maintains a FIFO object quarantine that stores up to the - specified number of bytes of memory. The quarantined memory is not - freed until it is released from quarantine, though it is immediately - junk-filled if the <link - linkend="opt.junk"><mallctl>opt.junk</mallctl></link> option is - enabled. This feature is of particular use in combination with <ulink - url="http://valgrind.org/">Valgrind</ulink>, which can detect attempts - to access quarantined objects. This is intended for debugging and will - impact performance negatively. The default quarantine size is 0 unless - running inside Valgrind, in which case the default is 16 - MiB.</para></listitem> - </varlistentry> - - <varlistentry id="opt.redzone"> - <term> - <mallctl>opt.redzone</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-fill</option>] - </term> - <listitem><para>Redzones enabled/disabled. If enabled, small - allocations have redzones before and after them. Furthermore, if the - <link linkend="opt.junk"><mallctl>opt.junk</mallctl></link> option is - enabled, the redzones are checked for corruption during deallocation. - However, the primary intended purpose of this feature is to be used in - combination with <ulink url="http://valgrind.org/">Valgrind</ulink>, - which needs redzones in order to do effective buffer overflow/underflow - detection. This option is intended for debugging and will impact - performance negatively. This option is disabled by - default unless running inside Valgrind.</para></listitem> - </varlistentry> - - <varlistentry id="opt.zero"> - <term> - <mallctl>opt.zero</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-fill</option>] - </term> - <listitem><para>Zero filling enabled/disabled. If enabled, each byte - of uninitialized allocated memory will be initialized to 0. Note that - this initialization only happens once for each byte, so - <function>realloc()</function> and - <function>rallocx()</function> calls do not zero memory that - was previously allocated. This is intended for debugging and will - impact performance negatively. This option is disabled by default. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.utrace"> - <term> - <mallctl>opt.utrace</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-utrace</option>] - </term> - <listitem><para>Allocation tracing based on - <citerefentry><refentrytitle>utrace</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> enabled/disabled. This option - is disabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.xmalloc"> - <term> - <mallctl>opt.xmalloc</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-xmalloc</option>] - </term> - <listitem><para>Abort-on-out-of-memory enabled/disabled. If enabled, - rather than returning failure for any allocation function, display a - diagnostic message on <constant>STDERR_FILENO</constant> and cause the - program to drop core (using - <citerefentry><refentrytitle>abort</refentrytitle> - <manvolnum>3</manvolnum></citerefentry>). If an application is - designed to depend on this behavior, set the option at compile time by - including the following in the source code: - <programlisting language="C"><![CDATA[ -malloc_conf = "xmalloc:true";]]></programlisting> - This option is disabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.tcache"> - <term> - <mallctl>opt.tcache</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Thread-specific caching (tcache) enabled/disabled. When - there are multiple threads, each thread uses a tcache for objects up to - a certain size. Thread-specific caching allows many allocations to be - satisfied without performing any thread synchronization, at the cost of - increased memory use. See the <link - linkend="opt.lg_tcache_max"><mallctl>opt.lg_tcache_max</mallctl></link> - option for related tuning information. This option is enabled by - default unless running inside <ulink - url="http://valgrind.org/">Valgrind</ulink>, in which case it is - forcefully disabled.</para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_tcache_max"> - <term> - <mallctl>opt.lg_tcache_max</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Maximum size class (log base 2) to cache in the - thread-specific cache (tcache). At a minimum, all small size classes - are cached, and at a maximum all large size classes are cached. The - default maximum is 32 KiB (2^15).</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof"> - <term> - <mallctl>opt.prof</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Memory profiling enabled/disabled. If enabled, profile - memory allocation activity. See the <link - linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link> - option for on-the-fly activation/deactivation. See the <link - linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link> - option for probabilistic sampling control. See the <link - linkend="opt.prof_accum"><mallctl>opt.prof_accum</mallctl></link> - option for control of cumulative sample reporting. See the <link - linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link> - option for information on interval-triggered profile dumping, the <link - linkend="opt.prof_gdump"><mallctl>opt.prof_gdump</mallctl></link> - option for information on high-water-triggered profile dumping, and the - <link linkend="opt.prof_final"><mallctl>opt.prof_final</mallctl></link> - option for final profile dumping. Profile output is compatible with - the <command>jeprof</command> command, which is based on the - <command>pprof</command> that is developed as part of the <ulink - url="http://code.google.com/p/gperftools/">gperftools - package</ulink>. See <link linkend="heap_profile_format">HEAP PROFILE - FORMAT</link> for heap profile format documentation.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_prefix"> - <term> - <mallctl>opt.prof_prefix</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Filename prefix for profile dumps. If the prefix is - set to the empty string, no automatic dumps will occur; this is - primarily useful for disabling the automatic final heap dump (which - also disables leak reporting, if enabled). The default prefix is - <filename>jeprof</filename>.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_active"> - <term> - <mallctl>opt.prof_active</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Profiling activated/deactivated. This is a secondary - control mechanism that makes it possible to start the application with - profiling enabled (see the <link - linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option) but - inactive, then toggle profiling at any time during program execution - with the <link - linkend="prof.active"><mallctl>prof.active</mallctl></link> mallctl. - This option is enabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_thread_active_init"> - <term> - <mallctl>opt.prof_thread_active_init</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Initial setting for <link - linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> - in newly created threads. The initial setting for newly created threads - can also be changed during execution via the <link - linkend="prof.thread_active_init"><mallctl>prof.thread_active_init</mallctl></link> - mallctl. This option is enabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_prof_sample"> - <term> - <mallctl>opt.lg_prof_sample</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Average interval (log base 2) between allocation - samples, as measured in bytes of allocation activity. Increasing the - sampling interval decreases profile fidelity, but also decreases the - computational overhead. The default sample interval is 512 KiB (2^19 - B).</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_accum"> - <term> - <mallctl>opt.prof_accum</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Reporting of cumulative object/byte counts in profile - dumps enabled/disabled. If this option is enabled, every unique - backtrace must be stored for the duration of execution. Depending on - the application, this can impose a large memory overhead, and the - cumulative counts are not always of interest. This option is disabled - by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_prof_interval"> - <term> - <mallctl>opt.lg_prof_interval</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Average interval (log base 2) between memory profile - dumps, as measured in bytes of allocation activity. The actual - interval between dumps may be sporadic because decentralized allocation - counters are used to avoid synchronization bottlenecks. Profiles are - dumped to files named according to the pattern - <filename><prefix>.<pid>.<seq>.i<iseq>.heap</filename>, - where <literal><prefix></literal> is controlled by the - <link - linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> - option. By default, interval-triggered profile dumping is disabled - (encoded as -1). - </para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_gdump"> - <term> - <mallctl>opt.prof_gdump</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Set the initial state of <link - linkend="prof.gdump"><mallctl>prof.gdump</mallctl></link>, which when - enabled triggers a memory profile dump every time the total virtual - memory exceeds the previous maximum. This option is disabled by - default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_final"> - <term> - <mallctl>opt.prof_final</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Use an - <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> function to dump final memory - usage to a file named according to the pattern - <filename><prefix>.<pid>.<seq>.f.heap</filename>, - where <literal><prefix></literal> is controlled by the <link - linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> - option. Note that <function>atexit()</function> may allocate - memory during application initialization and then deadlock internally - when jemalloc in turn calls <function>atexit()</function>, so - this option is not universally usable (though the application can - register its own <function>atexit()</function> function with - equivalent functionality). This option is disabled by - default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_leak"> - <term> - <mallctl>opt.prof_leak</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Leak reporting enabled/disabled. If enabled, use an - <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> function to report memory leaks - detected by allocation sampling. See the - <link linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option for - information on analyzing heap profile output. This option is disabled - by default.</para></listitem> - </varlistentry> - - <varlistentry id="thread.arena"> - <term> - <mallctl>thread.arena</mallctl> - (<type>unsigned</type>) - <literal>rw</literal> - </term> - <listitem><para>Get or set the arena associated with the calling - thread. If the specified arena was not initialized beforehand (see the - <link - linkend="arenas.initialized"><mallctl>arenas.initialized</mallctl></link> - mallctl), it will be automatically initialized as a side effect of - calling this interface.</para></listitem> - </varlistentry> - - <varlistentry id="thread.allocated"> - <term> - <mallctl>thread.allocated</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Get the total number of bytes ever allocated by the - calling thread. This counter has the potential to wrap around; it is - up to the application to appropriately interpret the counter in such - cases.</para></listitem> - </varlistentry> - - <varlistentry id="thread.allocatedp"> - <term> - <mallctl>thread.allocatedp</mallctl> - (<type>uint64_t *</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Get a pointer to the the value that is returned by the - <link - linkend="thread.allocated"><mallctl>thread.allocated</mallctl></link> - mallctl. This is useful for avoiding the overhead of repeated - <function>mallctl*()</function> calls.</para></listitem> - </varlistentry> - - <varlistentry id="thread.deallocated"> - <term> - <mallctl>thread.deallocated</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Get the total number of bytes ever deallocated by the - calling thread. This counter has the potential to wrap around; it is - up to the application to appropriately interpret the counter in such - cases.</para></listitem> - </varlistentry> - - <varlistentry id="thread.deallocatedp"> - <term> - <mallctl>thread.deallocatedp</mallctl> - (<type>uint64_t *</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Get a pointer to the the value that is returned by the - <link - linkend="thread.deallocated"><mallctl>thread.deallocated</mallctl></link> - mallctl. This is useful for avoiding the overhead of repeated - <function>mallctl*()</function> calls.</para></listitem> - </varlistentry> - - <varlistentry id="thread.tcache.enabled"> - <term> - <mallctl>thread.tcache.enabled</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Enable/disable calling thread's tcache. The tcache is - implicitly flushed as a side effect of becoming - disabled (see <link - linkend="thread.tcache.flush"><mallctl>thread.tcache.flush</mallctl></link>). - </para></listitem> - </varlistentry> - - <varlistentry id="thread.tcache.flush"> - <term> - <mallctl>thread.tcache.flush</mallctl> - (<type>void</type>) - <literal>--</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Flush calling thread's thread-specific cache (tcache). - This interface releases all cached objects and internal data structures - associated with the calling thread's tcache. Ordinarily, this interface - need not be called, since automatic periodic incremental garbage - collection occurs, and the thread cache is automatically discarded when - a thread exits. However, garbage collection is triggered by allocation - activity, so it is possible for a thread that stops - allocating/deallocating to retain its cache indefinitely, in which case - the developer may find manual flushing useful.</para></listitem> - </varlistentry> - - <varlistentry id="thread.prof.name"> - <term> - <mallctl>thread.prof.name</mallctl> - (<type>const char *</type>) - <literal>r-</literal> or - <literal>-w</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Get/set the descriptive name associated with the calling - thread in memory profile dumps. An internal copy of the name string is - created, so the input string need not be maintained after this interface - completes execution. The output string of this interface should be - copied for non-ephemeral uses, because multiple implementation details - can cause asynchronous string deallocation. Furthermore, each - invocation of this interface can only read or write; simultaneous - read/write is not supported due to string lifetime limitations. The - name string must be nil-terminated and comprised only of characters in - the sets recognized - by <citerefentry><refentrytitle>isgraph</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> and - <citerefentry><refentrytitle>isblank</refentrytitle> - <manvolnum>3</manvolnum></citerefentry>.</para></listitem> - </varlistentry> - - <varlistentry id="thread.prof.active"> - <term> - <mallctl>thread.prof.active</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Control whether sampling is currently active for the - calling thread. This is an activation mechanism in addition to <link - linkend="prof.active"><mallctl>prof.active</mallctl></link>; both must - be active for the calling thread to sample. This flag is enabled by - default.</para></listitem> - </varlistentry> - - <varlistentry id="tcache.create"> - <term> - <mallctl>tcache.create</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Create an explicit thread-specific cache (tcache) and - return an identifier that can be passed to the <link - linkend="MALLOCX_TCACHE"><constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant></link> - macro to explicitly use the specified cache rather than the - automatically managed one that is used by default. Each explicit cache - can be used by only one thread at a time; the application must assure - that this constraint holds. - </para></listitem> - </varlistentry> - - <varlistentry id="tcache.flush"> - <term> - <mallctl>tcache.flush</mallctl> - (<type>unsigned</type>) - <literal>-w</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Flush the specified thread-specific cache (tcache). The - same considerations apply to this interface as to <link - linkend="thread.tcache.flush"><mallctl>thread.tcache.flush</mallctl></link>, - except that the tcache will never be automatically discarded. - </para></listitem> - </varlistentry> - - <varlistentry id="tcache.destroy"> - <term> - <mallctl>tcache.destroy</mallctl> - (<type>unsigned</type>) - <literal>-w</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Flush the specified thread-specific cache (tcache) and - make the identifier available for use during a future tcache creation. - </para></listitem> - </varlistentry> - - <varlistentry id="arena.i.purge"> - <term> - <mallctl>arena.<i>.purge</mallctl> - (<type>void</type>) - <literal>--</literal> - </term> - <listitem><para>Purge all unused dirty pages for arena <i>, or for - all arenas if <i> equals <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link>. - </para></listitem> - </varlistentry> - - <varlistentry id="arena.i.decay"> - <term> - <mallctl>arena.<i>.decay</mallctl> - (<type>void</type>) - <literal>--</literal> - </term> - <listitem><para>Trigger decay-based purging of unused dirty pages for - arena <i>, or for all arenas if <i> equals <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link>. - The proportion of unused dirty pages to be purged depends on the current - time; see <link - linkend="opt.decay_time"><mallctl>opt.decay_time</mallctl></link> for - details.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.reset"> - <term> - <mallctl>arena.<i>.reset</mallctl> - (<type>void</type>) - <literal>--</literal> - </term> - <listitem><para>Discard all of the arena's extant allocations. This - interface can only be used with arenas created via <link - linkend="arenas.extend"><mallctl>arenas.extend</mallctl></link>. None - of the arena's discarded/cached allocations may accessed afterward. As - part of this requirement, all thread caches which were used to - allocate/deallocate in conjunction with the arena must be flushed - beforehand. This interface cannot be used if running inside Valgrind, - nor if the <link linkend="opt.quarantine">quarantine</link> size is - non-zero.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.dss"> - <term> - <mallctl>arena.<i>.dss</mallctl> - (<type>const char *</type>) - <literal>rw</literal> - </term> - <listitem><para>Set the precedence of dss allocation as related to mmap - allocation for arena <i>, or for all arenas if <i> equals - <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link>. See - <link linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for supported - settings.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.lg_dirty_mult"> - <term> - <mallctl>arena.<i>.lg_dirty_mult</mallctl> - (<type>ssize_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Current per-arena minimum ratio (log base 2) of active - to dirty pages for arena <i>. Each time this interface is set and - the ratio is increased, pages are synchronously purged as necessary to - impose the new ratio. See <link - linkend="opt.lg_dirty_mult"><mallctl>opt.lg_dirty_mult</mallctl></link> - for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.decay_time"> - <term> - <mallctl>arena.<i>.decay_time</mallctl> - (<type>ssize_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Current per-arena approximate time in seconds from the - creation of a set of unused dirty pages until an equivalent set of - unused dirty pages is purged and/or reused. Each time this interface is - set, all currently unused dirty pages are considered to have fully - decayed, which causes immediate purging of all unused dirty pages unless - the decay time is set to -1 (i.e. purging disabled). See <link - linkend="opt.decay_time"><mallctl>opt.decay_time</mallctl></link> for - additional information.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.chunk_hooks"> - <term> - <mallctl>arena.<i>.chunk_hooks</mallctl> - (<type>chunk_hooks_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Get or set the chunk management hook functions for arena - <i>. The functions must be capable of operating on all extant - chunks associated with arena <i>, usually by passing unknown - chunks to the replaced functions. In practice, it is feasible to - control allocation for arenas created via <link - linkend="arenas.extend"><mallctl>arenas.extend</mallctl></link> such - that all chunks originate from an application-supplied chunk allocator - (by setting custom chunk hook functions just after arena creation), but - the automatically created arenas may have already created chunks prior - to the application having an opportunity to take over chunk - allocation.</para> - - <programlisting language="C"><![CDATA[ -typedef struct { - chunk_alloc_t *alloc; - chunk_dalloc_t *dalloc; - chunk_commit_t *commit; - chunk_decommit_t *decommit; - chunk_purge_t *purge; - chunk_split_t *split; - chunk_merge_t *merge; -} chunk_hooks_t;]]></programlisting> - <para>The <type>chunk_hooks_t</type> structure comprises function - pointers which are described individually below. jemalloc uses these - functions to manage chunk lifetime, which starts off with allocation of - mapped committed memory, in the simplest case followed by deallocation. - However, there are performance and platform reasons to retain chunks for - later reuse. Cleanup attempts cascade from deallocation to decommit to - purging, which gives the chunk management functions opportunities to - reject the most permanent cleanup operations in favor of less permanent - (and often less costly) operations. The chunk splitting and merging - operations can also be opted out of, but this is mainly intended to - support platforms on which virtual memory mappings provided by the - operating system kernel do not automatically coalesce and split, e.g. - Windows.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef void *<function>(chunk_alloc_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>alignment</parameter></paramdef> - <paramdef>bool *<parameter>zero</parameter></paramdef> - <paramdef>bool *<parameter>commit</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>A chunk allocation function conforms to the - <type>chunk_alloc_t</type> type and upon success returns a pointer to - <parameter>size</parameter> bytes of mapped memory on behalf of arena - <parameter>arena_ind</parameter> such that the chunk's base address is a - multiple of <parameter>alignment</parameter>, as well as setting - <parameter>*zero</parameter> to indicate whether the chunk is zeroed and - <parameter>*commit</parameter> to indicate whether the chunk is - committed. Upon error the function returns <constant>NULL</constant> - and leaves <parameter>*zero</parameter> and - <parameter>*commit</parameter> unmodified. The - <parameter>size</parameter> parameter is always a multiple of the chunk - size. The <parameter>alignment</parameter> parameter is always a power - of two at least as large as the chunk size. Zeroing is mandatory if - <parameter>*zero</parameter> is true upon function entry. Committing is - mandatory if <parameter>*commit</parameter> is true upon function entry. - If <parameter>chunk</parameter> is not <constant>NULL</constant>, the - returned pointer must be <parameter>chunk</parameter> on success or - <constant>NULL</constant> on error. Committed memory may be committed - in absolute terms as on a system that does not overcommit, or in - implicit terms as on a system that overcommits and satisfies physical - memory needs on demand via soft page faults. Note that replacing the - default chunk allocation function makes the arena's <link - linkend="arena.i.dss"><mallctl>arena.<i>.dss</mallctl></link> - setting irrelevant.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(chunk_dalloc_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>bool <parameter>committed</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para> - A chunk deallocation function conforms to the - <type>chunk_dalloc_t</type> type and deallocates a - <parameter>chunk</parameter> of given <parameter>size</parameter> with - <parameter>committed</parameter>/decommited memory as indicated, on - behalf of arena <parameter>arena_ind</parameter>, returning false upon - success. If the function returns true, this indicates opt-out from - deallocation; the virtual memory mapping associated with the chunk - remains mapped, in the same commit state, and available for future use, - in which case it will be automatically retained for later reuse.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(chunk_commit_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>offset</parameter></paramdef> - <paramdef>size_t <parameter>length</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>A chunk commit function conforms to the - <type>chunk_commit_t</type> type and commits zeroed physical memory to - back pages within a <parameter>chunk</parameter> of given - <parameter>size</parameter> at <parameter>offset</parameter> bytes, - extending for <parameter>length</parameter> on behalf of arena - <parameter>arena_ind</parameter>, returning false upon success. - Committed memory may be committed in absolute terms as on a system that - does not overcommit, or in implicit terms as on a system that - overcommits and satisfies physical memory needs on demand via soft page - faults. If the function returns true, this indicates insufficient - physical memory to satisfy the request.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(chunk_decommit_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>offset</parameter></paramdef> - <paramdef>size_t <parameter>length</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>A chunk decommit function conforms to the - <type>chunk_decommit_t</type> type and decommits any physical memory - that is backing pages within a <parameter>chunk</parameter> of given - <parameter>size</parameter> at <parameter>offset</parameter> bytes, - extending for <parameter>length</parameter> on behalf of arena - <parameter>arena_ind</parameter>, returning false upon success, in which - case the pages will be committed via the chunk commit function before - being reused. If the function returns true, this indicates opt-out from - decommit; the memory remains committed and available for future use, in - which case it will be automatically retained for later reuse.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(chunk_purge_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> - <paramdef>size_t<parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>offset</parameter></paramdef> - <paramdef>size_t <parameter>length</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>A chunk purge function conforms to the <type>chunk_purge_t</type> - type and optionally discards physical pages within the virtual memory - mapping associated with <parameter>chunk</parameter> of given - <parameter>size</parameter> at <parameter>offset</parameter> bytes, - extending for <parameter>length</parameter> on behalf of arena - <parameter>arena_ind</parameter>, returning false if pages within the - purged virtual memory range will be zero-filled the next time they are - accessed.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(chunk_split_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>size_a</parameter></paramdef> - <paramdef>size_t <parameter>size_b</parameter></paramdef> - <paramdef>bool <parameter>committed</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>A chunk split function conforms to the <type>chunk_split_t</type> - type and optionally splits <parameter>chunk</parameter> of given - <parameter>size</parameter> into two adjacent chunks, the first of - <parameter>size_a</parameter> bytes, and the second of - <parameter>size_b</parameter> bytes, operating on - <parameter>committed</parameter>/decommitted memory as indicated, on - behalf of arena <parameter>arena_ind</parameter>, returning false upon - success. If the function returns true, this indicates that the chunk - remains unsplit and therefore should continue to be operated on as a - whole.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(chunk_merge_t)</function></funcdef> - <paramdef>void *<parameter>chunk_a</parameter></paramdef> - <paramdef>size_t <parameter>size_a</parameter></paramdef> - <paramdef>void *<parameter>chunk_b</parameter></paramdef> - <paramdef>size_t <parameter>size_b</parameter></paramdef> - <paramdef>bool <parameter>committed</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>A chunk merge function conforms to the <type>chunk_merge_t</type> - type and optionally merges adjacent chunks, - <parameter>chunk_a</parameter> of given <parameter>size_a</parameter> - and <parameter>chunk_b</parameter> of given - <parameter>size_b</parameter> into one contiguous chunk, operating on - <parameter>committed</parameter>/decommitted memory as indicated, on - behalf of arena <parameter>arena_ind</parameter>, returning false upon - success. If the function returns true, this indicates that the chunks - remain distinct mappings and therefore should continue to be operated on - independently.</para> - </listitem> - </varlistentry> - - <varlistentry id="arenas.narenas"> - <term> - <mallctl>arenas.narenas</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Current limit on number of arenas.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.initialized"> - <term> - <mallctl>arenas.initialized</mallctl> - (<type>bool *</type>) - <literal>r-</literal> - </term> - <listitem><para>An array of <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link> - booleans. Each boolean indicates whether the corresponding arena is - initialized.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.lg_dirty_mult"> - <term> - <mallctl>arenas.lg_dirty_mult</mallctl> - (<type>ssize_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Current default per-arena minimum ratio (log base 2) of - active to dirty pages, used to initialize <link - linkend="arena.i.lg_dirty_mult"><mallctl>arena.<i>.lg_dirty_mult</mallctl></link> - during arena creation. See <link - linkend="opt.lg_dirty_mult"><mallctl>opt.lg_dirty_mult</mallctl></link> - for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.decay_time"> - <term> - <mallctl>arenas.decay_time</mallctl> - (<type>ssize_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Current default per-arena approximate time in seconds - from the creation of a set of unused dirty pages until an equivalent set - of unused dirty pages is purged and/or reused, used to initialize <link - linkend="arena.i.decay_time"><mallctl>arena.<i>.decay_time</mallctl></link> - during arena creation. See <link - linkend="opt.decay_time"><mallctl>opt.decay_time</mallctl></link> for - additional information.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.quantum"> - <term> - <mallctl>arenas.quantum</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Quantum size.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.page"> - <term> - <mallctl>arenas.page</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Page size.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.tcache_max"> - <term> - <mallctl>arenas.tcache_max</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Maximum thread-cached size class.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.nbins"> - <term> - <mallctl>arenas.nbins</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of bin size classes.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.nhbins"> - <term> - <mallctl>arenas.nhbins</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - [<option>--enable-tcache</option>] - </term> - <listitem><para>Total number of thread cache bin size - classes.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.bin.i.size"> - <term> - <mallctl>arenas.bin.<i>.size</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum size supported by size class.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.bin.i.nregs"> - <term> - <mallctl>arenas.bin.<i>.nregs</mallctl> - (<type>uint32_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of regions per page run.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.bin.i.run_size"> - <term> - <mallctl>arenas.bin.<i>.run_size</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of bytes per page run.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.nlruns"> - <term> - <mallctl>arenas.nlruns</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Total number of large size classes.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.lrun.i.size"> - <term> - <mallctl>arenas.lrun.<i>.size</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum size supported by this large size - class.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.nhchunks"> - <term> - <mallctl>arenas.nhchunks</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Total number of huge size classes.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.hchunk.i.size"> - <term> - <mallctl>arenas.hchunk.<i>.size</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum size supported by this huge size - class.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.extend"> - <term> - <mallctl>arenas.extend</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Extend the array of arenas by appending a new arena, - and returning the new arena index.</para></listitem> - </varlistentry> - - <varlistentry id="prof.thread_active_init"> - <term> - <mallctl>prof.thread_active_init</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Control the initial setting for <link - linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> - in newly created threads. See the <link - linkend="opt.prof_thread_active_init"><mallctl>opt.prof_thread_active_init</mallctl></link> - option for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="prof.active"> - <term> - <mallctl>prof.active</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Control whether sampling is currently active. See the - <link - linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link> - option for additional information, as well as the interrelated <link - linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> - mallctl.</para></listitem> - </varlistentry> - - <varlistentry id="prof.dump"> - <term> - <mallctl>prof.dump</mallctl> - (<type>const char *</type>) - <literal>-w</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Dump a memory profile to the specified file, or if NULL - is specified, to a file according to the pattern - <filename><prefix>.<pid>.<seq>.m<mseq>.heap</filename>, - where <literal><prefix></literal> is controlled by the - <link - linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> - option.</para></listitem> - </varlistentry> - - <varlistentry id="prof.gdump"> - <term> - <mallctl>prof.gdump</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>When enabled, trigger a memory profile dump every time - the total virtual memory exceeds the previous maximum. Profiles are - dumped to files named according to the pattern - <filename><prefix>.<pid>.<seq>.u<useq>.heap</filename>, - where <literal><prefix></literal> is controlled by the <link - linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> - option.</para></listitem> - </varlistentry> - - <varlistentry id="prof.reset"> - <term> - <mallctl>prof.reset</mallctl> - (<type>size_t</type>) - <literal>-w</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Reset all memory profile statistics, and optionally - update the sample rate (see <link - linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link> - and <link - linkend="prof.lg_sample"><mallctl>prof.lg_sample</mallctl></link>). - </para></listitem> - </varlistentry> - - <varlistentry id="prof.lg_sample"> - <term> - <mallctl>prof.lg_sample</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Get the current sample rate (see <link - linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link>). - </para></listitem> - </varlistentry> - - <varlistentry id="prof.interval"> - <term> - <mallctl>prof.interval</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Average number of bytes allocated between - interval-based profile dumps. See the - <link - linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link> - option for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="stats.cactive"> - <term> - <mallctl>stats.cactive</mallctl> - (<type>size_t *</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Pointer to a counter that contains an approximate count - of the current number of bytes in active pages. The estimate may be - high, but never low, because each arena rounds up when computing its - contribution to the counter. Note that the <link - linkend="epoch"><mallctl>epoch</mallctl></link> mallctl has no bearing - on this counter. Furthermore, counter consistency is maintained via - atomic operations, so it is necessary to use an atomic operation in - order to guarantee a consistent read when dereferencing the pointer. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.allocated"> - <term> - <mallctl>stats.allocated</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes allocated by the - application.</para></listitem> - </varlistentry> - - <varlistentry id="stats.active"> - <term> - <mallctl>stats.active</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes in active pages allocated by the - application. This is a multiple of the page size, and greater than or - equal to <link - linkend="stats.allocated"><mallctl>stats.allocated</mallctl></link>. - This does not include <link linkend="stats.arenas.i.pdirty"> - <mallctl>stats.arenas.<i>.pdirty</mallctl></link>, nor pages - entirely devoted to allocator metadata.</para></listitem> - </varlistentry> - - <varlistentry id="stats.metadata"> - <term> - <mallctl>stats.metadata</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes dedicated to metadata, which - comprise base allocations used for bootstrap-sensitive internal - allocator data structures, arena chunk headers (see <link - linkend="stats.arenas.i.metadata.mapped"><mallctl>stats.arenas.<i>.metadata.mapped</mallctl></link>), - and internal allocations (see <link - linkend="stats.arenas.i.metadata.allocated"><mallctl>stats.arenas.<i>.metadata.allocated</mallctl></link>).</para></listitem> - </varlistentry> - - <varlistentry id="stats.resident"> - <term> - <mallctl>stats.resident</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Maximum number of bytes in physically resident data - pages mapped by the allocator, comprising all pages dedicated to - allocator metadata, pages backing active allocations, and unused dirty - pages. This is a maximum rather than precise because pages may not - actually be physically resident if they correspond to demand-zeroed - virtual memory that has not yet been touched. This is a multiple of the - page size, and is larger than <link - linkend="stats.active"><mallctl>stats.active</mallctl></link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.mapped"> - <term> - <mallctl>stats.mapped</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes in active chunks mapped by the - allocator. This is a multiple of the chunk size, and is larger than - <link linkend="stats.active"><mallctl>stats.active</mallctl></link>. - This does not include inactive chunks, even those that contain unused - dirty pages, which means that there is no strict ordering between this - and <link - linkend="stats.resident"><mallctl>stats.resident</mallctl></link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.retained"> - <term> - <mallctl>stats.retained</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes in virtual memory mappings that - were retained rather than being returned to the operating system via - e.g. <citerefentry><refentrytitle>munmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>. Retained virtual memory is - typically untouched, decommitted, or purged, so it has no strongly - associated physical memory (see <link - linkend="arena.i.chunk_hooks">chunk hooks</link> for details). Retained - memory is excluded from mapped memory statistics, e.g. <link - linkend="stats.mapped"><mallctl>stats.mapped</mallctl></link>. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.dss"> - <term> - <mallctl>stats.arenas.<i>.dss</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>dss (<citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>) allocation precedence as - related to <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> allocation. See <link - linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for details. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lg_dirty_mult"> - <term> - <mallctl>stats.arenas.<i>.lg_dirty_mult</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Minimum ratio (log base 2) of active to dirty pages. - See <link - linkend="opt.lg_dirty_mult"><mallctl>opt.lg_dirty_mult</mallctl></link> - for details.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.decay_time"> - <term> - <mallctl>stats.arenas.<i>.decay_time</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Approximate time in seconds from the creation of a set - of unused dirty pages until an equivalent set of unused dirty pages is - purged and/or reused. See <link - linkend="opt.decay_time"><mallctl>opt.decay_time</mallctl></link> - for details.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.nthreads"> - <term> - <mallctl>stats.arenas.<i>.nthreads</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of threads currently assigned to - arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.pactive"> - <term> - <mallctl>stats.arenas.<i>.pactive</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of pages in active runs.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.pdirty"> - <term> - <mallctl>stats.arenas.<i>.pdirty</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of pages within unused runs that are potentially - dirty, and for which <function>madvise<parameter>...</parameter> - <parameter><constant>MADV_DONTNEED</constant></parameter></function> or - similar has not been called.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mapped"> - <term> - <mallctl>stats.arenas.<i>.mapped</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of mapped bytes.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.retained"> - <term> - <mallctl>stats.arenas.<i>.retained</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of retained bytes. See <link - linkend="stats.retained"><mallctl>stats.retained</mallctl></link> for - details.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.metadata.mapped"> - <term> - <mallctl>stats.arenas.<i>.metadata.mapped</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of mapped bytes in arena chunk headers, which - track the states of the non-metadata pages.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.metadata.allocated"> - <term> - <mallctl>stats.arenas.<i>.metadata.allocated</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of bytes dedicated to internal allocations. - Internal allocations differ from application-originated allocations in - that they are for internal use, and that they are omitted from heap - profiles. This statistic is reported separately from <link - linkend="stats.metadata"><mallctl>stats.metadata</mallctl></link> and - <link - linkend="stats.arenas.i.metadata.mapped"><mallctl>stats.arenas.<i>.metadata.mapped</mallctl></link> - because it overlaps with e.g. the <link - linkend="stats.allocated"><mallctl>stats.allocated</mallctl></link> and - <link linkend="stats.active"><mallctl>stats.active</mallctl></link> - statistics, whereas the other metadata statistics do - not.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.npurge"> - <term> - <mallctl>stats.arenas.<i>.npurge</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of dirty page purge sweeps performed. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.nmadvise"> - <term> - <mallctl>stats.arenas.<i>.nmadvise</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of <function>madvise<parameter>...</parameter> - <parameter><constant>MADV_DONTNEED</constant></parameter></function> or - similar calls made to purge dirty pages.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.purged"> - <term> - <mallctl>stats.arenas.<i>.purged</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of pages purged.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.small.allocated"> - <term> - <mallctl>stats.arenas.<i>.small.allocated</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of bytes currently allocated by small objects. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.small.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.small.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests served by - small bins.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.small.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.small.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of small objects returned to bins. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.small.nrequests"> - <term> - <mallctl>stats.arenas.<i>.small.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of small allocation requests. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.large.allocated"> - <term> - <mallctl>stats.arenas.<i>.large.allocated</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of bytes currently allocated by large objects. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.large.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.large.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of large allocation requests served - directly by the arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.large.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.large.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of large deallocation requests served - directly by the arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.large.nrequests"> - <term> - <mallctl>stats.arenas.<i>.large.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of large allocation requests. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.huge.allocated"> - <term> - <mallctl>stats.arenas.<i>.huge.allocated</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of bytes currently allocated by huge objects. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.huge.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.huge.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of huge allocation requests served - directly by the arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.huge.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.huge.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of huge deallocation requests served - directly by the arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.huge.nrequests"> - <term> - <mallctl>stats.arenas.<i>.huge.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of huge allocation requests. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocations served by bin. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocations returned to bin. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nrequests"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation - requests.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.curregs"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.curregs</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Current number of regions for this size - class.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nfills"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nfills</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option> <option>--enable-tcache</option>] - </term> - <listitem><para>Cumulative number of tcache fills.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nflushes"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nflushes</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option> <option>--enable-tcache</option>] - </term> - <listitem><para>Cumulative number of tcache flushes.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nruns"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nruns</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of runs created.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nreruns"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nreruns</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times the current run from which - to allocate changed.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.curruns"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.curruns</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Current number of runs.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lruns.j.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.lruns.<j>.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests for this size - class served directly by the arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lruns.j.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.lruns.<j>.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of deallocation requests for this - size class served directly by the arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lruns.j.nrequests"> - <term> - <mallctl>stats.arenas.<i>.lruns.<j>.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests for this size - class.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lruns.j.curruns"> - <term> - <mallctl>stats.arenas.<i>.lruns.<j>.curruns</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Current number of runs for this size class. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.hchunks.j.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.hchunks.<j>.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests for this size - class served directly by the arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.hchunks.j.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.hchunks.<j>.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of deallocation requests for this - size class served directly by the arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.hchunks.j.nrequests"> - <term> - <mallctl>stats.arenas.<i>.hchunks.<j>.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests for this size - class.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.hchunks.j.curhchunks"> - <term> - <mallctl>stats.arenas.<i>.hchunks.<j>.curhchunks</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Current number of huge allocations for this size class. - </para></listitem> - </varlistentry> - </variablelist> - </refsect1> - <refsect1 id="heap_profile_format"> - <title>HEAP PROFILE FORMAT</title> - <para>Although the heap profiling functionality was originally designed to - be compatible with the - <command>pprof</command> command that is developed as part of the <ulink - url="http://code.google.com/p/gperftools/">gperftools - package</ulink>, the addition of per thread heap profiling functionality - required a different heap profile format. The <command>jeprof</command> - command is derived from <command>pprof</command>, with enhancements to - support the heap profile format described here.</para> - - <para>In the following hypothetical heap profile, <constant>[...]</constant> - indicates elision for the sake of compactness. <programlisting><![CDATA[ -heap_v2/524288 - t*: 28106: 56637512 [0: 0] - [...] - t3: 352: 16777344 [0: 0] - [...] - t99: 17754: 29341640 [0: 0] - [...] -@ 0x5f86da8 0x5f5a1dc [...] 0x29e4d4e 0xa200316 0xabb2988 [...] - t*: 13: 6688 [0: 0] - t3: 12: 6496 [0: ] - t99: 1: 192 [0: 0] -[...] - -MAPPED_LIBRARIES: -[...]]]></programlisting> The following matches the above heap profile, but most -tokens are replaced with <constant><description></constant> to indicate -descriptions of the corresponding fields. <programlisting><![CDATA[ -<heap_profile_format_version>/<mean_sample_interval> - <aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] - [...] - <thread_3_aggregate>: <curobjs>: <curbytes>[<cumobjs>: <cumbytes>] - [...] - <thread_99_aggregate>: <curobjs>: <curbytes>[<cumobjs>: <cumbytes>] - [...] -@ <top_frame> <frame> [...] <frame> <frame> <frame> [...] - <backtrace_aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] - <backtrace_thread_3>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] - <backtrace_thread_99>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] -[...] - -MAPPED_LIBRARIES: -</proc/<pid>/maps>]]></programlisting></para> - </refsect1> - - <refsect1 id="debugging_malloc_problems"> - <title>DEBUGGING MALLOC PROBLEMS</title> - <para>When debugging, it is a good idea to configure/build jemalloc with - the <option>--enable-debug</option> and <option>--enable-fill</option> - options, and recompile the program with suitable options and symbols for - debugger support. When so configured, jemalloc incorporates a wide variety - of run-time assertions that catch application errors such as double-free, - write-after-free, etc.</para> - - <para>Programs often accidentally depend on <quote>uninitialized</quote> - memory actually being filled with zero bytes. Junk filling - (see the <link linkend="opt.junk"><mallctl>opt.junk</mallctl></link> - option) tends to expose such bugs in the form of obviously incorrect - results and/or coredumps. Conversely, zero - filling (see the <link - linkend="opt.zero"><mallctl>opt.zero</mallctl></link> option) eliminates - the symptoms of such bugs. Between these two options, it is usually - possible to quickly detect, diagnose, and eliminate such bugs.</para> - - <para>This implementation does not provide much detail about the problems - it detects, because the performance impact for storing such information - would be prohibitive. However, jemalloc does integrate with the most - excellent <ulink url="http://valgrind.org/">Valgrind</ulink> tool if the - <option>--enable-valgrind</option> configuration option is enabled.</para> - </refsect1> - <refsect1 id="diagnostic_messages"> - <title>DIAGNOSTIC MESSAGES</title> - <para>If any of the memory allocation/deallocation functions detect an - error or warning condition, a message will be printed to file descriptor - <constant>STDERR_FILENO</constant>. Errors will result in the process - dumping core. If the <link - linkend="opt.abort"><mallctl>opt.abort</mallctl></link> option is set, most - warnings are treated as errors.</para> - - <para>The <varname>malloc_message</varname> variable allows the programmer - to override the function which emits the text strings forming the errors - and warnings if for some reason the <constant>STDERR_FILENO</constant> file - descriptor is not suitable for this. - <function>malloc_message()</function> takes the - <parameter>cbopaque</parameter> pointer argument that is - <constant>NULL</constant> unless overridden by the arguments in a call to - <function>malloc_stats_print()</function>, followed by a string - pointer. Please note that doing anything which tries to allocate memory in - this function is likely to result in a crash or deadlock.</para> - - <para>All messages are prefixed by - <quote><computeroutput><jemalloc>: </computeroutput></quote>.</para> - </refsect1> - <refsect1 id="return_values"> - <title>RETURN VALUES</title> - <refsect2> - <title>Standard API</title> - <para>The <function>malloc()</function> and - <function>calloc()</function> functions return a pointer to the - allocated memory if successful; otherwise a <constant>NULL</constant> - pointer is returned and <varname>errno</varname> is set to - <errorname>ENOMEM</errorname>.</para> - - <para>The <function>posix_memalign()</function> function - returns the value 0 if successful; otherwise it returns an error value. - The <function>posix_memalign()</function> function will fail - if: - <variablelist> - <varlistentry> - <term><errorname>EINVAL</errorname></term> - - <listitem><para>The <parameter>alignment</parameter> parameter is - not a power of 2 at least as large as - <code language="C">sizeof(<type>void *</type>)</code>. - </para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>ENOMEM</errorname></term> - - <listitem><para>Memory allocation error.</para></listitem> - </varlistentry> - </variablelist> - </para> - - <para>The <function>aligned_alloc()</function> function returns - a pointer to the allocated memory if successful; otherwise a - <constant>NULL</constant> pointer is returned and - <varname>errno</varname> is set. The - <function>aligned_alloc()</function> function will fail if: - <variablelist> - <varlistentry> - <term><errorname>EINVAL</errorname></term> - - <listitem><para>The <parameter>alignment</parameter> parameter is - not a power of 2. - </para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>ENOMEM</errorname></term> - - <listitem><para>Memory allocation error.</para></listitem> - </varlistentry> - </variablelist> - </para> - - <para>The <function>realloc()</function> function returns a - pointer, possibly identical to <parameter>ptr</parameter>, to the - allocated memory if successful; otherwise a <constant>NULL</constant> - pointer is returned, and <varname>errno</varname> is set to - <errorname>ENOMEM</errorname> if the error was the result of an - allocation failure. The <function>realloc()</function> - function always leaves the original buffer intact when an error occurs. - </para> - - <para>The <function>free()</function> function returns no - value.</para> - </refsect2> - <refsect2> - <title>Non-standard API</title> - <para>The <function>mallocx()</function> and - <function>rallocx()</function> functions return a pointer to - the allocated memory if successful; otherwise a <constant>NULL</constant> - pointer is returned to indicate insufficient contiguous memory was - available to service the allocation request. </para> - - <para>The <function>xallocx()</function> function returns the - real size of the resulting resized allocation pointed to by - <parameter>ptr</parameter>, which is a value less than - <parameter>size</parameter> if the allocation could not be adequately - grown in place. </para> - - <para>The <function>sallocx()</function> function returns the - real size of the allocation pointed to by <parameter>ptr</parameter>. - </para> - - <para>The <function>nallocx()</function> returns the real size - that would result from a successful equivalent - <function>mallocx()</function> function call, or zero if - insufficient memory is available to perform the size computation. </para> - - <para>The <function>mallctl()</function>, - <function>mallctlnametomib()</function>, and - <function>mallctlbymib()</function> functions return 0 on - success; otherwise they return an error value. The functions will fail - if: - <variablelist> - <varlistentry> - <term><errorname>EINVAL</errorname></term> - - <listitem><para><parameter>newp</parameter> is not - <constant>NULL</constant>, and <parameter>newlen</parameter> is too - large or too small. Alternatively, <parameter>*oldlenp</parameter> - is too large or too small; in this case as much data as possible - are read despite the error.</para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>ENOENT</errorname></term> - - <listitem><para><parameter>name</parameter> or - <parameter>mib</parameter> specifies an unknown/invalid - value.</para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>EPERM</errorname></term> - - <listitem><para>Attempt to read or write void value, or attempt to - write read-only value.</para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>EAGAIN</errorname></term> - - <listitem><para>A memory allocation failure - occurred.</para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>EFAULT</errorname></term> - - <listitem><para>An interface with side effects failed in some way - not directly related to <function>mallctl*()</function> - read/write processing.</para></listitem> - </varlistentry> - </variablelist> - </para> - - <para>The <function>malloc_usable_size()</function> function - returns the usable size of the allocation pointed to by - <parameter>ptr</parameter>. </para> - </refsect2> - </refsect1> - <refsect1 id="environment"> - <title>ENVIRONMENT</title> - <para>The following environment variable affects the execution of the - allocation functions: - <variablelist> - <varlistentry> - <term><envar>MALLOC_CONF</envar></term> - - <listitem><para>If the environment variable - <envar>MALLOC_CONF</envar> is set, the characters it contains - will be interpreted as options.</para></listitem> - </varlistentry> - </variablelist> - </para> - </refsect1> - <refsect1 id="examples"> - <title>EXAMPLES</title> - <para>To dump core whenever a problem occurs: - <screen>ln -s 'abort:true' /etc/malloc.conf</screen> - </para> - <para>To specify in the source a chunk size that is 16 MiB: - <programlisting language="C"><![CDATA[ -malloc_conf = "lg_chunk:24";]]></programlisting></para> - </refsect1> - <refsect1 id="see_also"> - <title>SEE ALSO</title> - <para><citerefentry><refentrytitle>madvise</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, - <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, - <citerefentry><refentrytitle>utrace</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, - <citerefentry><refentrytitle>alloca</refentrytitle> - <manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>getpagesize</refentrytitle> - <manvolnum>3</manvolnum></citerefentry></para> - </refsect1> - <refsect1 id="standards"> - <title>STANDARDS</title> - <para>The <function>malloc()</function>, - <function>calloc()</function>, - <function>realloc()</function>, and - <function>free()</function> functions conform to ISO/IEC - 9899:1990 (<quote>ISO C90</quote>).</para> - - <para>The <function>posix_memalign()</function> function conforms - to IEEE Std 1003.1-2001 (<quote>POSIX.1</quote>).</para> - </refsect1> -</refentry> |