[webkit-changes] [WebKit/WebKit] 02ebac: [libpas] Use VA-based memory-zeroing for very larg...

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 02ebac79609f9cbb858facadf8346ee3eaae361f
      https://github.com/WebKit/WebKit/commit/02ebac79609f9cbb858facadf8346ee3eaae361f
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2023-08-08 (Tue, 08 Aug 2023)

  Changed paths:
    M Source/bmalloc/CMakeLists.txt
    M Source/bmalloc/bmalloc.xcodeproj/project.pbxproj
    M Source/bmalloc/libpas/libpas.xcodeproj/project.pbxproj
    A Source/bmalloc/libpas/src/libpas/pas_allocation_result.c
    M Source/bmalloc/libpas/src/libpas/pas_allocation_result.h
    M Source/bmalloc/libpas/src/libpas/pas_internal_config.h

  Log Message:
  -----------
  [libpas] Use VA-based memory-zeroing for very large allocations
https://bugs.webkit.org/show_bug.cgi?id=259938
rdar://113577292

Reviewed by Keith Miller.

Let's try using VA-based zeroing for very large allocations in libpas.
VA-based one has some cost, but still useful if the allocated memory is not used
so much actually. We already have a path avoiding this zeroing if the allocated VA
is already zero, but if not, let's take this path to zeroing them via mmap.

* Source/bmalloc/CMakeLists.txt:
* Source/bmalloc/bmalloc.xcodeproj/project.pbxproj:
* Source/bmalloc/libpas/libpas.xcodeproj/project.pbxproj:
* Source/bmalloc/libpas/src/libpas/pas_allocation_result.c: Added.
(pas_allocation_result_zero_large_slow):
* Source/bmalloc/libpas/src/libpas/pas_allocation_result.h:
(pas_allocation_result_zero):
* Source/bmalloc/libpas/src/libpas/pas_internal_config.h:

Canonical link: https://commits.webkit.org/266698@main