kiper220/mimalloc
1
0
Fork 0
mirror of https://github.com/microsoft/mimalloc.git synced 2025-05-08 00:09:31 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions

use MADV_DONTNEED for commit/decommit on macOS

Browse source
This commit is contained in:
daan 2020-09-06 12:06:56 -07:00
parent 5ae01fe4d9
commit 828613a694
1 changed files with 19 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
src/os.c
View file

@ -716,20 +716,35 @@ static bool mi_os_commitx(void* addr, size_t size, bool commit, bool conservativ
#elif defined(__wasi__)
// WebAssembly guests can't control memory protection
#elif defined(MAP_FIXED) && !defined(__APPLE__)
// Linux
if (!commit) {
// use mmap with MAP_FIXED to discard the existing memory (and reduce commit charge)
// decommit: use mmap with MAP_FIXED to discard the existing memory (and reduce rss)
const int fd = mi_unix_mmap_fd();
void* p = mmap(start, csize, PROT_NONE, (MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE), fd, 0);
if (p != start) { err = errno; }
}
else {
// for commit, just change the protection
// commit: just change the protection
err = mprotect(start, csize, (PROT_READ | PROT_WRITE));
if (err != 0) { err = errno; }
}
#else
err = mprotect(start, csize, (commit ? (PROT_READ | PROT_WRITE) : PROT_NONE));
if (err != 0) { err = errno; }
// MacOS and others.
if (!commit) {
#if defined(MADV_DONTNEED)
// decommit: use MADV_DONTNEED as it decrease rss immediately (unlike MADV_FREE)
err = madvise(start, csize, MADV_DONTNEED);
#else
// decommit: just disable access
err = mprotect(start, csize, PROT_NONE);
if (err != 0) { err = errno; }
#endif
}
else {
// commit: ensure we can access the area
err = mprotect(start, csize, (PROT_READ | PROT_WRITE));
if (err != 0) { err = errno; }
}
#endif
if (err != 0) {
_mi_warning_message("%s error: start: %p, csize: 0x%x, err: %i\n", commit ? "commit" : "decommit", start, csize, err);