mirrors/mimalloc
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

use hinted address to mmap to reduce mmap calls

Browse Source
This commit is contained in:
daan 2019-07-21 17:08:09 -07:00
parent df33efb19a
commit 069f52523f
1 changed files with 23 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
src/os.c
View File

@ -10,6 +10,7 @@ terms of the MIT license. A copy of the license can be found in the file
#include "mimalloc.h"
#include "mimalloc-internal.h"
#include "mimalloc-atomic.h"
#include <string.h> // memset
#include <errno.h>
@ -242,6 +243,23 @@ static void* mi_wasm_heap_grow(size_t size, size_t try_alignment) {
return (void*) aligned_base;
}
#else
static void* mi_unix_mmapx(size_t size, size_t try_alignment, int protect_flags, int flags, int fd) {
void* p = NULL;
#if (MI_INTPTR_SIZE >= 8) && !defined(MAP_ALIGNED)
// on 64-bit systems, use a special area for 4MiB aligned allocations
static volatile intptr_t aligned_base = ((intptr_t)1 << 42); // starting at 4TiB
if (try_alignment <= MI_SEGMENT_SIZE && (size%MI_SEGMENT_SIZE)==0 && (aligned_base%try_alignment)==0) {
intptr_t hint = mi_atomic_add(&aligned_base,size) - size;
p = mmap((void*)hint,size,protect_flags,flags,fd,0);
if (p==MAP_FAILED) p = NULL; // fall back to regular mmap
}
#endif
if (p==NULL) {
p = mmap(NULL,size,protect_flags,flags,fd,0);
}
return p;
}
static void* mi_unix_mmap(size_t size, size_t try_alignment, int protect_flags) {
void* p = NULL;
#if !defined(MAP_ANONYMOUS)
@ -278,12 +296,12 @@ static void* mi_unix_mmap(size_t size, size_t try_alignment, int protect_flags)
// try large page allocation
// TODO: if always failing due to permissions or no huge pages, try to avoid repeatedly trying?
// Should we check this in _mi_os_init? (as on Windows)
p = mmap(NULL, size, protect_flags, lflags, fd, 0);
p = mi_unix_mmapx(size, try_alignment, protect_flags, lflags, fd);
if (p == MAP_FAILED) p = NULL; // fall back to regular mmap if large is exhausted or no permission
}
}
if (p == NULL) {
p = mmap(NULL, size, protect_flags, flags, -1, 0);
p = mi_unix_mmapx(size, try_alignment, protect_flags, flags, -1);
if (p == MAP_FAILED) p = NULL;
}
return p;
@ -439,7 +457,7 @@ static void* mi_os_page_align_area_conservative(void* addr, size_t size, size_t*
return mi_os_page_align_areax(true, addr, size, newsize);
}
// Commit/Decommit memory.
// Commit/Decommit memory.
// Usuelly commit is aligned liberal, while decommit is aligned conservative.
// (but not for the reset version where we want commit to be conservative as well)
static bool mi_os_commitx(void* addr, size_t size, bool commit, bool conservative, mi_stats_t* stats) {
@ -503,7 +521,7 @@ static bool mi_os_resetx(void* addr, size_t size, bool reset, mi_stats_t* stats)
else _mi_stat_decrease(&stats->reset, csize);
if (!reset) return true; // nothing to do on unreset!
#if (MI_DEBUG>1)
#if (MI_DEBUG>1)
if (!mi_option_is_enabled(mi_option_secure)) {
memset(start, 0, csize); // pretend it is eagerly reset
}
@ -521,7 +539,7 @@ static bool mi_os_resetx(void* addr, size_t size, bool reset, mi_stats_t* stats)
void* p = VirtualAlloc(start, csize, MEM_RESET, PAGE_READWRITE);
mi_assert_internal(p == start);
if (p != start) return false;
}
}
#else
#if defined(MADV_FREE)
static int advice = MADV_FREE;