446096 - Integrate upstream jemalloc optimizations

Status: RESOLVED FIXED

(Core :: Memory Allocator, enhancement)

Description

[Jason Evans]

The upstream (FreeBSD) jemalloc contains substantial speed and space optimizations that we should integrate.

Comment 1

[Jason Evans]

Attachment: Integrate upstream optimizations

Enhance arena_chunk_map_t to directly support run coalescing, and use
the chunk map instead of red-black trees where possible.  Remove the
red-black trees and node objects that are obsoleted by this change.  The
net result is a ~1-2% memory savings, and a substantial allocation speed
improvement.

Comment 2

[Jason Evans]

I forgot to note that the patch also introduces a radix tree that is used to substantially simplify and speed up isalloc_validate().  This makes checking whether object pointers reside within memory managed by jemalloc much faster.

isalloc_validate() is heavily used by the OS X port (see bug #414946).  The radix tree may end up being critical on Windows as well if 

Comment 3

[Jason Evans]

[continuation of comment #2]

[... critical on Windows if] we add a Mozilla-specific allocation API separate from the standard malloc() (moz_malloc(), moz_free(), etc.) in order to allow mixed allocator use for cases where a custom CRT cannot be used.

Comment 4

[Jason Evans]

changeset:   16218:d6bbea319540
user:        Jason Evans <[e-mail]>
date:        Fri Jul 25 14:53:20 2008 -0700
summary:     Bug 446096: Integrate upstream jemalloc optimizations, r=pavlov