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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /mfbt/TaggedAnonymousMemory.h | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'mfbt/TaggedAnonymousMemory.h')
-rw-r--r-- | mfbt/TaggedAnonymousMemory.h | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/mfbt/TaggedAnonymousMemory.h b/mfbt/TaggedAnonymousMemory.h new file mode 100644 index 000000000..d26b06dfb --- /dev/null +++ b/mfbt/TaggedAnonymousMemory.h @@ -0,0 +1,86 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +// Some Linux kernels -- specifically, newer versions of Android and +// some B2G devices -- have a feature for assigning names to ranges of +// anonymous memory (i.e., memory that doesn't have a "name" in the +// form of an underlying mapped file). These names are reported in +// /proc/<pid>/smaps alongside system-level memory usage information +// such as Proportional Set Size (memory usage adjusted for sharing +// between processes), which allows reporting this information at a +// finer granularity than would otherwise be possible (e.g., +// separating malloc() heap from JS heap). +// +// Existing memory can be tagged with MozTagAnonymousMemory(); it will +// tag the range of complete pages containing the given interval, so +// the results may be inexact if the range isn't page-aligned. +// MozTaggedAnonymousMmap() can be used like mmap() with an extra +// parameter, and will tag the returned memory if the mapping was +// successful (and if it was in fact anonymous). +// +// NOTE: The pointer given as the "tag" argument MUST remain valid as +// long as the mapping exists. The referenced string is read when +// /proc/<pid>/smaps or /proc/<pid>/maps is read, not when the tag is +// established, so freeing it or changing its contents will have +// unexpected results. Using a static string is probably best. +// +// Also note that this header can be used by both C and C++ code. + +#ifndef mozilla_TaggedAnonymousMemory_h +#define mozilla_TaggedAnonymousMemory_h + +#ifndef XP_WIN + +#include <sys/types.h> +#include <sys/mman.h> + +#include "mozilla/Types.h" + +#ifdef ANDROID + +#ifdef __cplusplus +extern "C" { +#endif + +MFBT_API void +MozTagAnonymousMemory(const void* aPtr, size_t aLength, const char* aTag); + +MFBT_API void* +MozTaggedAnonymousMmap(void* aAddr, size_t aLength, int aProt, int aFlags, + int aFd, off_t aOffset, const char* aTag); + +MFBT_API int +MozTaggedMemoryIsSupported(void); + +#ifdef __cplusplus +} // extern "C" +#endif + +#else // ANDROID + +static inline void +MozTagAnonymousMemory(const void* aPtr, size_t aLength, const char* aTag) +{ +} + +static inline void* +MozTaggedAnonymousMmap(void* aAddr, size_t aLength, int aProt, int aFlags, + int aFd, off_t aOffset, const char* aTag) +{ + return mmap(aAddr, aLength, aProt, aFlags, aFd, aOffset); +} + +static inline int +MozTaggedMemoryIsSupported(void) +{ + return 0; +} + +#endif // ANDROID + +#endif // !XP_WIN + +#endif // mozilla_TaggedAnonymousMemory_h |