Remove support for making jemalloc4 the default memory allocator.

12 files changed, 32 insertions, 439 deletions

diff --git a/build/autoconf/jemalloc.m4 b/build/autoconf/jemalloc.m4
index eae4e4d3a..21fed27e9 100644
--- a/build/autoconf/jemalloc.m4
+++ b/build/autoconf/jemalloc.m4
@@ -8,7 +8,7 @@ if test "$MOZ_BUILD_APP" != js -o -n "$JS_STANDALONE"; then
 
   # Run jemalloc configure script
 
-  if test "$MOZ_MEMORY" && test -n "$MOZ_JEMALLOC4" -o -n "$MOZ_REPLACE_MALLOC"; then
+  if test "$MOZ_MEMORY" && test -n "$MOZ_REPLACE_MALLOC"; then
     ac_configure_args="--build=$build --host=$target --enable-stats --with-jemalloc-prefix=je_ --disable-valgrind"
     # We're using memalign for _aligned_malloc in memory/build/mozmemory_wrap.c
     # on Windows, so just export memalign on all platforms.
@@ -22,41 +22,8 @@ if test "$MOZ_BUILD_APP" != js -o -n "$JS_STANDALONE"; then
         ac_configure_args="$ac_configure_args --enable-ivsalloc"
       fi
     fi
-    if test -n "$MOZ_JEMALLOC4"; then
-      case "${OS_ARCH}" in
-        WINNT|Darwin)
-          # We want jemalloc functions to be kept hidden on both Mac and Windows
-          # See memory/build/mozmemory_wrap.h for details.
-          ac_configure_args="$ac_configure_args --without-export"
-          ;;
-      esac
-      if test "${OS_ARCH}" = WINNT; then
-        # Lazy lock initialization doesn't play well with lazy linking of
-        # mozglue.dll on Windows XP (leads to startup crash), so disable it.
-        ac_configure_args="$ac_configure_args --disable-lazy-lock"
-
-        # 64-bit Windows builds require a minimum 16-byte alignment.
-        if test -n "$HAVE_64BIT_BUILD"; then
-          ac_configure_args="$ac_configure_args --with-lg-tiny-min=4"
-        fi
-      fi
-    elif test "${OS_ARCH}" = Darwin; then
-      # When building as a replace-malloc lib, disabling the zone allocator
-      # forces to use pthread_atfork.
-      ac_configure_args="$ac_configure_args --disable-zone-allocator"
-    fi
-    _MANGLE="malloc posix_memalign aligned_alloc calloc realloc free memalign valloc malloc_usable_size"
-    JEMALLOC_WRAPPER=
-    if test -z "$MOZ_REPLACE_MALLOC"; then
-      case "$OS_ARCH" in
-        Linux|DragonFly|FreeBSD|NetBSD|OpenBSD)
-          MANGLE=$_MANGLE
-          ;;
-      esac
-    elif test -z "$MOZ_JEMALLOC4"; then
-      MANGLE=$_MANGLE
-      JEMALLOC_WRAPPER=replace_
-    fi
+    MANGLE="malloc posix_memalign aligned_alloc calloc realloc free memalign valloc malloc_usable_size"
+    JEMALLOC_WRAPPER=replace_
     if test -n "$MANGLE"; then
       MANGLED=
       for mangle in ${MANGLE}; do
diff --git a/build/moz.configure/memory.configure b/build/moz.configure/memory.configure
index 3beed2fb2..398413b62 100644
--- a/build/moz.configure/memory.configure
+++ b/build/moz.configure/memory.configure
@@ -5,12 +5,13 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 
-option(env='MOZ_JEMALLOC4', help='Enable jemalloc 4')
-imply_option('--enable-jemalloc', depends_if('MOZ_JEMALLOC4')(lambda x: '4'))
+@deprecated_option(env='MOZ_JEMALLOC4')
+def moz_jemalloc4(value):
+    die('MOZ_JEMALLOC4 is no longer supported')
 
 
-option('--enable-jemalloc', nargs='?', choices=('4', 'moz'), env='MOZ_MEMORY',
-       help='Replace memory allocator with jemalloc')
+option('--enable-jemalloc', env='MOZ_MEMORY',
+       help='Replace system memory allocator with jemalloc')
 
 @depends('--enable-jemalloc', target, build_project, c_compiler)
 def jemalloc(value, target, build_project, c_compiler):
@@ -30,36 +31,25 @@ def jemalloc(value, target, build_project, c_compiler):
     if target.kernel == 'Linux':
         return True
 
-@depends('--enable-jemalloc')
-def jemalloc4(jemalloc):
-    if len(jemalloc) and jemalloc[0] == '4':
-        return True
-
 
 set_config('MOZ_MEMORY', jemalloc)
 set_define('MOZ_MEMORY', jemalloc)
 add_old_configure_assignment('MOZ_MEMORY', jemalloc)
 
-set_config('MOZ_JEMALLOC4', jemalloc4)
-set_define('MOZ_JEMALLOC4', jemalloc4)
-add_old_configure_assignment('MOZ_JEMALLOC4', jemalloc4)
-
 
 # Because --enable-jemalloc doesn't use a default because of the dependency
 # on the target, we can't use a js_option for it to propagate to js/src
 # through the old-configure.
-@depends(jemalloc, jemalloc4)
-def jemalloc_for_old_configure(jemalloc, jemalloc4):
-    if jemalloc:
-        return '--enable-jemalloc=4' if jemalloc4 else '--enable-jemalloc'
-    return '--disable-jemalloc'
+@depends(jemalloc)
+def jemalloc_for_old_configure(jemalloc):
+    return '--%s-jemalloc' % ('enable' if jemalloc else 'disable')
 
 add_old_configure_arg(jemalloc_for_old_configure)
 
 
-@depends(jemalloc, jemalloc4, target)
-def jemalloc_os_define(jemalloc, jemalloc4, target):
-    if jemalloc and not jemalloc4:
+@depends(jemalloc, target)
+def jemalloc_os_define(jemalloc, target):
+    if jemalloc:
         if target.kernel == 'WINNT':
             return 'MOZ_MEMORY_WINDOWS'
         if target.kernel == 'Linux':
@@ -72,9 +62,9 @@ def jemalloc_os_define(jemalloc, jemalloc4, target):
 
 set_define(jemalloc_os_define, '1')
 
-@depends(jemalloc, jemalloc4, target)
-def jemalloc_os_define_android(jemalloc, jemalloc4, target):
-    if jemalloc and not jemalloc4 and target.os == 'Android':
+@depends(jemalloc, target)
+def jemalloc_os_define_android(jemalloc, target):
+    if jemalloc and target.os == 'Android':
         return 'MOZ_MEMORY_ANDROID'
 
 set_define(jemalloc_os_define_android, '1')
diff --git a/js/xpconnect/src/XPCJSContext.cpp b/js/xpconnect/src/XPCJSContext.cpp
index f5f6a11bb..8862bca32 100644
--- a/js/xpconnect/src/XPCJSContext.cpp
+++ b/js/xpconnect/src/XPCJSContext.cpp
@@ -59,10 +59,6 @@
 #include "nsIXULRuntime.h"
 #include "nsJSPrincipals.h"
 
-#if defined(MOZ_JEMALLOC4)
-#include "mozmemory.h"
-#endif
-
 #ifdef XP_WIN
 #include <windows.h>
 #endif
@@ -147,18 +143,6 @@ public:
               mActive = false;
           }
       } else {
-#if defined(MOZ_JEMALLOC4)
-          if (mPurge) {
-              /* Jemalloc purges dirty pages regularly during free() when the
-               * ratio of dirty pages compared to active pages is higher than
-               * 1 << lg_dirty_mult. A high ratio can have an impact on
-               * performance, so we use the default ratio of 8, but force a
-               * regular purge of all remaining dirty pages, after cycle
-               * collection. */
-              Telemetry::AutoTimer<Telemetry::MEMORY_FREE_PURGED_PAGES_MS> timer;
-              jemalloc_free_dirty_pages();
-          }
-#endif
           mActive = false;
       }
       return NS_OK;
diff --git a/memory/build/jemalloc_config.cpp b/memory/build/jemalloc_config.cpp
index 1a83c79e2..0b734d804 100644
--- a/memory/build/jemalloc_config.cpp
+++ b/memory/build/jemalloc_config.cpp
@@ -2,157 +2,7 @@
  * 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/. */
 
-#ifdef MOZ_JEMALLOC4
-
-#define MOZ_JEMALLOC_IMPL
-
-/* mozmemory_wrap.h needs to be included before MFBT headers */
-#include "mozmemory_wrap.h"
-#include <mozilla/Assertions.h>
-#include "mozilla/Types.h"
-
-#define DLLEXPORT
-#include "jemalloc/jemalloc.h"
-
-#ifdef XP_WIN
-#include <windows.h>
-#endif
-#ifdef XP_DARWIN
-#include <sys/mman.h>
-#endif
-
-/* Override some jemalloc defaults */
-#ifdef DEBUG
-#define MOZ_MALLOC_BUILD_OPTIONS ",junk:true"
-#else
-#define MOZ_MALLOC_BUILD_OPTIONS ",junk:free"
-#endif
-
-#define MOZ_MALLOC_OPTIONS "narenas:1,tcache:false"
-MFBT_DATA const char* je_(malloc_conf) =
-  MOZ_MALLOC_OPTIONS MOZ_MALLOC_BUILD_OPTIONS;
-
-#ifdef ANDROID
-#include <android/log.h>
-
-static void
-_je_malloc_message(void* cbopaque, const char* s)
-{
-  __android_log_print(ANDROID_LOG_INFO, "GeckoJemalloc", "%s", s);
-}
-
-void (*je_(malloc_message))(void*, const char* s) = _je_malloc_message;
-#endif
-
-/* Jemalloc supports hooks that are called on chunk
- * allocate/deallocate/commit/decommit/purge/etc.
- *
- * We currently only hook commit, decommit and purge. We do this to tweak
- * the way chunks are handled so that RSS stays lower than it normally
- * would with the default jemalloc uses.
- * This somewhat matches the behavior of mozjemalloc, except it doesn't
- * rely on a double purge on mac, instead purging directly. (Yes, this
- * means we can get rid of jemalloc_purge_freed_pages at some point)
- *
- * The default for jemalloc is to do the following:
- * - commit, decommit: nothing
- * - purge: MEM_RESET on Windows, MADV_FREE on Mac/BSD, MADV_DONTNEED on Linux
- *
- * The hooks we setup do the following:
- * on Windows:
- * - commit: MEM_COMMIT
- * - decommit: MEM_DECOMMIT
- * on Mac:
- * - purge: mmap new anonymous memory on top of the chunk
- *
- * We only set the above hooks, others are left with the default.
- */
-#if defined(XP_WIN) || defined(XP_DARWIN)
-class JemallocInit {
-public:
-  JemallocInit()
-  {
-    chunk_hooks_t hooks;
-    size_t hooks_len;
-    unsigned narenas;
-    size_t mib[3];
-    size_t size;
-
-    size = sizeof(narenas);
-    je_(mallctl)("arenas.narenas", &narenas, &size, nullptr, 0);
-
-    size = sizeof(mib) / sizeof(mib[0]);
-    je_(mallctlnametomib)("arena.0.chunk_hooks", mib, &size);
-
-    /* Set the hooks on all the existing arenas. */
-    for (unsigned arena = 0; arena < narenas; arena++) {
-      mib[1] = arena;
-      hooks_len = sizeof(hooks);
-      je_(mallctlbymib)(mib, size, &hooks, &hooks_len, nullptr, 0);
-
-#ifdef XP_WIN
-      hooks.commit = CommitHook;
-      hooks.decommit = DecommitHook;
-#endif
-#ifdef XP_DARWIN
-      hooks.purge = PurgeHook;
-#endif
-
-      je_(mallctlbymib)(mib, size, nullptr, nullptr, &hooks, hooks_len);
-    }
-  }
-
-private:
-#ifdef XP_WIN
-  static bool
-  CommitHook(void* chunk, size_t size, size_t offset, size_t length,
-             unsigned arena_ind)
-  {
-    void* addr = reinterpret_cast<void*>(
-      reinterpret_cast<uintptr_t>(chunk) + static_cast<uintptr_t>(offset));
-
-    if (!VirtualAlloc(addr, length, MEM_COMMIT, PAGE_READWRITE))
-      return true;
-
-    return false;
-  }
-
-  static bool
-  DecommitHook(void* chunk, size_t size, size_t offset, size_t length,
-               unsigned arena_ind)
-  {
-    void* addr = reinterpret_cast<void*>(
-      reinterpret_cast<uintptr_t>(chunk) + static_cast<uintptr_t>(offset));
-
-    if (!VirtualFree(addr, length, MEM_DECOMMIT))
-      MOZ_CRASH();
-
-    return false;
-  }
-#endif
-
-#ifdef XP_DARWIN
-  static bool
-  PurgeHook(void* chunk, size_t size, size_t offset, size_t length,
-            unsigned arena_ind)
-  {
-    void* addr = reinterpret_cast<void*>(
-      reinterpret_cast<uintptr_t>(chunk) + static_cast<uintptr_t>(offset));
-
-    void* new_addr = mmap(addr, length, PROT_READ | PROT_WRITE,
-                          MAP_FIXED | MAP_PRIVATE | MAP_ANON, -1, 0);
-    return (new_addr != addr);
-  }
-#endif
-};
-
-/* For the static constructor from the class above */
-JemallocInit gJemallocInit;
-#endif
-
-#else
 #include <mozilla/Assertions.h>
-#endif /* MOZ_JEMALLOC4 */
 
 /* Provide an abort function for use in jemalloc code */
 extern "C" void moz_abort() {
diff --git a/memory/build/moz.build b/memory/build/moz.build
index bd6c2503e..f4fd82878 100644
--- a/memory/build/moz.build
+++ b/memory/build/moz.build
@@ -24,16 +24,6 @@ SOURCES += [
     'mozmemory_wrap.c',
 ]
 
-if CONFIG['MOZ_JEMALLOC4']:
-    SOURCES += [
-        'mozjemalloc_compat.c',
-    ]
-    LOCAL_INCLUDES += ['!../jemalloc/src/include']
-    if CONFIG['_MSC_VER']:
-        LOCAL_INCLUDES += ['/memory/jemalloc/src/include/msvc_compat']
-        if not CONFIG['HAVE_INTTYPES_H']:
-            LOCAL_INCLUDES += ['/memory/jemalloc/src/include/msvc_compat/C99']
-
 if CONFIG['MOZ_REPLACE_MALLOC']:
     SOURCES += [
         'replace_malloc.c',
@@ -49,6 +39,3 @@ if CONFIG['MOZ_GLUE_IN_PROGRAM']:
 if CONFIG['MOZ_MEMORY'] and CONFIG['OS_TARGET'] in ('WINNT', 'Darwin', 'Android'):
     FINAL_LIBRARY = 'mozglue'
 
-if CONFIG['MOZ_REPLACE_MALLOC'] and CONFIG['OS_TARGET'] == 'Darwin':
-    # The zone allocator for OSX needs some jemalloc internal functions
-    LOCAL_INCLUDES += ['/memory/jemalloc/src/include']
diff --git a/memory/build/mozjemalloc_compat.c b/memory/build/mozjemalloc_compat.c
deleted file mode 100644
index 0b3b333d4..000000000
--- a/memory/build/mozjemalloc_compat.c
+++ /dev/null
@@ -1,178 +0,0 @@
-/* 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/. */
-
-#ifndef MOZ_JEMALLOC4
-#  error Should only compile this file when building with jemalloc 3
-#endif
-
-#define MOZ_JEMALLOC_IMPL
-
-#include "mozmemory_wrap.h"
-#include "jemalloc_types.h"
-#include "mozilla/Types.h"
-
-#include <stdbool.h>
-
-#include "jemalloc/jemalloc.h"
-
-/*
- *  CTL_* macros are from memory/jemalloc/src/src/stats.c with changes:
- *  - drop `t' argument to avoid redundancy in calculating type size
- *  - require `i' argument for arena number explicitly
- */
-
-#define	CTL_GET(n, v) do {						\
-	size_t sz = sizeof(v);						\
-	je_(mallctl)(n, &v, &sz, NULL, 0);				\
-} while (0)
-
-#define	CTL_I_GET(n, v, i) do {						\
-	size_t mib[6];							\
-	size_t miblen = sizeof(mib) / sizeof(mib[0]);			\
-	size_t sz = sizeof(v);						\
-	je_(mallctlnametomib)(n, mib, &miblen);			\
-	mib[2] = i;							\
-	je_(mallctlbymib)(mib, miblen, &v, &sz, NULL, 0);		\
-} while (0)
-
-#define	CTL_IJ_GET(n, v, i, j) do {					\
-	size_t mib[6];							\
-	size_t miblen = sizeof(mib) / sizeof(mib[0]);			\
-	size_t sz = sizeof(v);						\
-	je_(mallctlnametomib)(n, mib, &miblen);				\
-	mib[2] = i;							\
-	mib[4] = j;							\
-	je_(mallctlbymib)(mib, miblen, &v, &sz, NULL, 0);			\
-} while (0)
-
-/*
- * VARIABLE_ARRAY is copied from
- * memory/jemalloc/src/include/jemalloc/internal/jemalloc_internal.h.in
- */
-#if __STDC_VERSION__ < 199901L
-#  ifdef _MSC_VER
-#    include <malloc.h>
-#    define alloca _alloca
-#  else
-#    ifdef HAVE_ALLOCA_H
-#      include <alloca.h>
-#    else
-#      include <stdlib.h>
-#    endif
-#  endif
-#  define VARIABLE_ARRAY(type, name, count) \
-	type *name = alloca(sizeof(type) * (count))
-#else
-#  define VARIABLE_ARRAY(type, name, count) type name[(count)]
-#endif
-
-MOZ_MEMORY_API size_t
-malloc_good_size_impl(size_t size)
-{
-  /* je_nallocx crashes when given a size of 0. As
-   * malloc_usable_size(malloc(0)) and malloc_usable_size(malloc(1))
-   * return the same value, use a size of 1. */
-  if (size == 0)
-    size = 1;
-  return je_(nallocx)(size, 0);
-}
-
-static void
-compute_bin_unused_and_bookkeeping(jemalloc_stats_t *stats, unsigned int narenas)
-{
-    size_t bin_unused = 0;
-
-    uint32_t nregs; // number of regions per run in the j-th bin
-    size_t reg_size; // size of regions served by the j-th bin
-    size_t curruns; // number of runs belonging to a bin
-    size_t curregs; // number of allocated regions in a bin
-
-    unsigned int nbins; // number of bins per arena
-    unsigned int i, j;
-
-    size_t stats_metadata;
-    size_t stats_ametadata = 0; // total internal allocations in all arenas
-
-    // narenas also counts uninitialized arenas, and initialized arenas
-    // are not guaranteed to be adjacent
-    VARIABLE_ARRAY(bool, initialized, narenas);
-    size_t isz = sizeof(initialized) / sizeof(initialized[0]);
-
-    je_(mallctl)("arenas.initialized", initialized, &isz, NULL, 0);
-    CTL_GET("arenas.nbins", nbins);
-
-    for (j = 0; j < nbins; j++) {
-        CTL_I_GET("arenas.bin.0.nregs", nregs, j);
-        CTL_I_GET("arenas.bin.0.size", reg_size, j);
-
-        for (i = 0; i < narenas; i++) {
-            if (!initialized[i]) {
-                continue;
-            }
-
-            CTL_IJ_GET("stats.arenas.0.bins.0.curruns", curruns, i, j);
-            CTL_IJ_GET("stats.arenas.0.bins.0.curregs", curregs, i, j);
-
-            bin_unused += (nregs * curruns - curregs) * reg_size;
-        }
-    }
-
-    CTL_GET("stats.metadata", stats_metadata);
-
-    /* get the summation for all arenas, i == narenas */
-    CTL_I_GET("stats.arenas.0.metadata.allocated", stats_ametadata, narenas);
-
-    stats->bookkeeping = stats_metadata - stats_ametadata;
-    stats->bin_unused = bin_unused;
-}
-
-MOZ_JEMALLOC_API void
-jemalloc_stats_impl(jemalloc_stats_t *stats)
-{
-  unsigned narenas;
-  size_t active, allocated, mapped, page, pdirty;
-  size_t lg_chunk;
-
-  // Refresh jemalloc's stats by updating its epoch, see ctl_refresh in
-  // src/ctl.c
-  uint64_t epoch = 0;
-  size_t esz = sizeof(epoch);
-  je_(mallctl)("epoch", &epoch, &esz, &epoch, esz);
-
-  CTL_GET("arenas.narenas", narenas);
-  CTL_GET("arenas.page", page);
-  CTL_GET("stats.active", active);
-  CTL_GET("stats.allocated", allocated);
-  CTL_GET("stats.mapped", mapped);
-  CTL_GET("opt.lg_chunk", lg_chunk);
-
-  /* get the summation for all arenas, i == narenas */
-  CTL_I_GET("stats.arenas.0.pdirty", pdirty, narenas);
-
-  stats->chunksize = (size_t) 1 << lg_chunk;
-  stats->mapped = mapped;
-  stats->allocated = allocated;
-  stats->waste = active - allocated;
-  stats->page_cache = pdirty * page;
-  compute_bin_unused_and_bookkeeping(stats, narenas);
-  stats->waste -= stats->bin_unused;
-}
-
-MOZ_JEMALLOC_API void
-jemalloc_purge_freed_pages_impl()
-{
-}
-
-MOZ_JEMALLOC_API void
-jemalloc_free_dirty_pages_impl()
-{
-  unsigned narenas;
-  size_t mib[3];
-  size_t miblen = sizeof(mib) / sizeof(mib[0]);
-
-  CTL_GET("arenas.narenas", narenas);
-  je_(mallctlnametomib)("arena.0.purge", mib, &miblen);
-  mib[1] = narenas;
-  je_(mallctlbymib)(mib, miblen, NULL, NULL, NULL, 0);
-}
diff --git a/memory/jemalloc/moz.build b/memory/jemalloc/moz.build
index b7e2b661f..e2c3f002e 100644
--- a/memory/jemalloc/moz.build
+++ b/memory/jemalloc/moz.build
@@ -46,10 +46,7 @@ if CONFIG['OS_TARGET'] == 'Darwin' and not CONFIG['MOZ_REPLACE_MALLOC']:
         'src/src/zone.c',
     ]
 
-if CONFIG['MOZ_JEMALLOC4']:
-    FINAL_LIBRARY = 'memory'
-else:
-    FINAL_LIBRARY = 'replace_jemalloc'
+FINAL_LIBRARY = 'replace_jemalloc'
 
 if CONFIG['MOZ_GLUE_IN_PROGRAM']:
     SDK_LIBRARY = True
diff --git a/memory/moz.build b/memory/moz.build
index bdf262293..7f7559f3a 100644
--- a/memory/moz.build
+++ b/memory/moz.build
@@ -20,7 +20,7 @@ if CONFIG['MOZ_MEMORY']:
         'mozjemalloc',
     ]
 
-    if CONFIG['MOZ_JEMALLOC4'] or CONFIG['MOZ_REPLACE_MALLOC']:
+    if CONFIG['MOZ_REPLACE_MALLOC']:
         DIRS += ['jemalloc']
 
     if CONFIG['MOZ_REPLACE_MALLOC']:
diff --git a/memory/mozjemalloc/moz.build b/memory/mozjemalloc/moz.build
index 0660d1300..feeb4fb07 100644
--- a/memory/mozjemalloc/moz.build
+++ b/memory/mozjemalloc/moz.build
@@ -8,16 +8,15 @@ EXPORTS += [
     'jemalloc_types.h',
 ]
 
-if not CONFIG['MOZ_JEMALLOC4']:
-    SOURCES += [
-        'jemalloc.c',
-    ]
-    FINAL_LIBRARY = 'memory'
-
-    # See bug 422055.
-    if CONFIG['OS_ARCH'] == 'SunOS' and not CONFIG['GNU_CC'] \
-            and CONFIG['MOZ_OPTIMIZE']:
-        CFLAGS += ['-xO5']
+SOURCES += [
+    'jemalloc.c',
+]
+FINAL_LIBRARY = 'memory'
+
+# See bug 422055.
+if CONFIG['OS_ARCH'] == 'SunOS' and not CONFIG['GNU_CC'] \
+        and CONFIG['MOZ_OPTIMIZE']:
+    CFLAGS += ['-xO5']
 
 # For non release/esr builds, enable (some) fatal jemalloc assertions.  This
 # helps us catch memory errors.
diff --git a/memory/replace/logalloc/replay/Replay.cpp b/memory/replace/logalloc/replay/Replay.cpp
index 30fcd21e5..0ae20de2c 100644
--- a/memory/replace/logalloc/replay/Replay.cpp
+++ b/memory/replace/logalloc/replay/Replay.cpp
@@ -286,7 +286,7 @@ MOZ_BEGIN_EXTERN_C
 
 /* mozjemalloc relies on DllMain to initialize, but DllMain is not invoked
  * for executables, so manually invoke mozjemalloc initialization. */
-#if defined(_WIN32) && !defined(MOZ_JEMALLOC4)
+#if defined(_WIN32)
 void malloc_init_hard(void);
 #endif
 
@@ -475,7 +475,7 @@ main()
   FdReader reader(0);
   Replay replay;
 
-#if defined(_WIN32) && !defined(MOZ_JEMALLOC4)
+#if defined(_WIN32)
   malloc_init_hard();
 #endif
 
diff --git a/memory/replace/moz.build b/memory/replace/moz.build
index 111b8456b..1f29da7aa 100644
--- a/memory/replace/moz.build
+++ b/memory/replace/moz.build
@@ -9,9 +9,8 @@ DIRS += [
     'replace',
 ]
 
-# Build jemalloc3 as a replace-malloc lib when building with mozjemalloc
-if not CONFIG['MOZ_JEMALLOC4']:
-    DIRS += ['jemalloc']
+# Build jemalloc4 as a replace-malloc lib when building with mozjemalloc
+DIRS += ['jemalloc']
 
 if CONFIG['MOZ_REPLACE_MALLOC_LINKAGE'] == 'dummy library':
     DIRS += ['dummy']
diff --git a/xpcom/base/nsMemoryReporterManager.cpp b/xpcom/base/nsMemoryReporterManager.cpp
index aa3d74dfd..616eefbdc 100644
--- a/xpcom/base/nsMemoryReporterManager.cpp
+++ b/xpcom/base/nsMemoryReporterManager.cpp
@@ -439,13 +439,11 @@ static MOZ_MUST_USE nsresult
 ResidentDistinguishedAmountHelper(int64_t* aN, bool aDoPurge)
 {
 #ifdef HAVE_JEMALLOC_STATS
-#ifndef MOZ_JEMALLOC4
   if (aDoPurge) {
     Telemetry::AutoTimer<Telemetry::MEMORY_FREE_PURGED_PAGES_MS> timer;
     jemalloc_purge_freed_pages();
   }
 #endif
-#endif
 
   task_basic_info ti;
   if (!GetTaskBasicInfo(&ti)) {