Jemalloc 4 purges dirty pages regularly during free() when the ratio of dirty
pages compared to active pages is higher than 1 << lg_dirty_mult. We set
lg_dirty_mult in jemalloc_config to limit RSS usage, but it also has an impact
on performance.
So instead of enforcing a high ratio to force more pages being purged, we keep
jemalloc's default ratio of 8, and force a regular purge of all dirty pages,
after cycle collection.
Keeping jemalloc's default ratio avoids cycle-collection-triggered purge to
have to go through really all dirty pages when there are a lot, in which case
the normal jemalloc purge during free() will already have kicked in. It also
takes care of everything that doesn't run the cycle collector still having
a level of purge, like plugins in the plugin-container.
At the same time, since jemalloc_purge_freed_pages does nothing with jemalloc 4,
repurpose the MEMORY_FREE_PURGED_PAGES_MS telemetry probe to track the time
spent in this cycle-collector-triggered purge.
The patch removes 455 occurrences of FAIL_ON_WARNINGS from moz.build files, and
adds 78 instances of ALLOW_COMPILER_WARNINGS. About half of those 78 are in
code we control and which should be removable with a little effort.
Now that we have moz.build, we can be guaranteed that any flags we add
in moz.build will be added after everything else has been setup. So any
uses of MODULE_OPTIMIZE_FLAGS can be moved to moz.build's
CFLAGS/CXXFLAGS without any unusual repercussions. We do have to verify
that MOZ_OPTIMIZE is in effect, though.
The bulk of this commit was generated by running:
run-clang-tidy.py \
-checks='-*,llvm-namespace-comment' \
-header-filter=^/.../mozilla-central/.* \
-fix
This adds a new option --clamp-contents to dmd.py. This replaces every value
contained in the memory contents in the log with a pointer to the start of a live
block, if the value is a pointer into the middle of that block. All other values
are replaced with 0. This conservative analysis makes it easier to determine
which blocks point to other blocks.
This implements a new "scan" mode for DMD that records the address
and contents of every live unsampled block in the DMD log. This
enables the low-level analysis of references from one block to
another, which can help leak investigations.
Bug 1168719 added a generic replace malloc library which name happened to be
the same as the existing dummy library used to link replace malloc on OSX.
Change the name of that dummy library.
They are kept around for the sake of the standalone glue, which is used
for e.g. webapprt, which doesn't have direct access to jemalloc, and thus
still needs a wrapper to go through the xpcom function list and get to
jemalloc from there.
Sometimes, at least on Linux, DMDFuncs::sSingleton's static initializer
(in libxul) was being called before sDMDBridge's (in libdmd).
Thus sDMDBridge wasn't constructed yet in the path where its
address is taken, passed down through {replace_,}get_bridge to
ReplaceMallocBridge::Get, and its mVersion field is read.
This patch uses dynamic allocation, following what's done for other
globals in the same situation in this file.
Also, naming convention fix: leading "s" is for C++ class statics;
C-style static globals should be "g".
