kiper220/mimalloc
1
0
Fork 0
mirror of https://github.com/microsoft/mimalloc.git synced 2025-05-04 22:49:32 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions

revise decommit on linux in debug/secure mode

Browse source
This commit is contained in:
daanx 2023-04-23 20:32:22 -07:00
parent 4b2f6448cb
commit bfe2651ec9
1 changed files with 21 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

37
src/prim/unix/prim.c
View file

@ -209,28 +209,33 @@ static void* unix_mmap_prim(void* addr, size_t size, size_t try_alignment, int p
return NULL; return NULL;
} }
static int unix_mmap_fd(void) {
#if defined(VM_MAKE_TAG)
// macOS: tracking anonymous page with a specific ID. (All up to 98 are taken officially but LLVM sanitizers had taken 99)
int os_tag = (int)mi_option_get(mi_option_os_tag);
if (os_tag < 100 || os_tag > 255) { os_tag = 100; }
return VM_MAKE_TAG(os_tag);
#else
return -1;
#endif
}
static void* unix_mmap(void* addr, size_t size, size_t try_alignment, int protect_flags, bool large_only, bool allow_large, bool* is_large) { static void* unix_mmap(void* addr, size_t size, size_t try_alignment, int protect_flags, bool large_only, bool allow_large, bool* is_large) {
void* p = NULL;
#if !defined(MAP_ANONYMOUS) #if !defined(MAP_ANONYMOUS)
#define MAP_ANONYMOUS MAP_ANON #define MAP_ANONYMOUS MAP_ANON
#endif #endif
#if !defined(MAP_NORESERVE) #if !defined(MAP_NORESERVE)
#define MAP_NORESERVE 0 #define MAP_NORESERVE 0
#endif #endif
void* p = NULL;
const int fd = unix_mmap_fd();
int flags = MAP_PRIVATE | MAP_ANONYMOUS; int flags = MAP_PRIVATE | MAP_ANONYMOUS;
int fd = -1;
if (_mi_os_has_overcommit()) { if (_mi_os_has_overcommit()) {
flags |= MAP_NORESERVE; flags |= MAP_NORESERVE;
} }
#if defined(PROT_MAX) #if defined(PROT_MAX)
protect_flags |= PROT_MAX(PROT_READ | PROT_WRITE); // BSD protect_flags |= PROT_MAX(PROT_READ | PROT_WRITE); // BSD
#endif #endif
#if defined(VM_MAKE_TAG)
// macOS: tracking anonymous page with a specific ID. (All up to 98 are taken officially but LLVM sanitizers had taken 99)
int os_tag = (int)mi_option_get(mi_option_os_tag);
if (os_tag < 100 || os_tag > 255) { os_tag = 100; }
fd = VM_MAKE_TAG(os_tag);
#endif
// huge page allocation // huge page allocation
if ((large_only || _mi_os_use_large_page(size, try_alignment)) && allow_large) { if ((large_only || _mi_os_use_large_page(size, try_alignment)) && allow_large) {
static _Atomic(size_t) large_page_try_ok; // = 0; static _Atomic(size_t) large_page_try_ok; // = 0;
@ -363,21 +368,21 @@ int _mi_prim_decommit(void* start, size_t size, bool* needs_recommit) {
int err = 0; int err = 0;
#if defined(MADV_DONTNEED) && !MI_DEBUG && !MI_SECURE #if defined(MADV_DONTNEED) && !MI_DEBUG && !MI_SECURE
// decommit: use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE) // decommit: use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE)
// (on the other hand, MADV_FREE would be good enough.. it is just not reflected in the stats :-( )
*needs_recommit = false; *needs_recommit = false;
err = unix_madvise(start, size, MADV_DONTNEED); err = unix_madvise(start, size, MADV_DONTNEED);
#else #else
// decommit: just disable access (also used in debug and secure mode to trap on illegal access) // decommit: use mmap with MAP_FIXED and PROT_NONE to discard the existing memory (and reduce rss)
*needs_recommit = true; // needs recommit to reuse the memory *needs_recommit = true;
err = mprotect(start, size, PROT_NONE); const int fd = unix_mmap_fd();
if (err != 0) { err = errno; } void* p = mmap(start, size, PROT_NONE, (MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE), fd, 0);
if (p != start) { err = errno; }
#endif #endif
return err; return err;
} }
int _mi_prim_reset(void* start, size_t size) { int _mi_prim_reset(void* start, size_t size) {
// We always use MADV_DONTNEED even if it may be a bit more expensive as this // We always use MADV_DONTNEED if possible even if it may be a bit more expensive as MADV_FREE
// guarantees that we see the actual rss reflected in tools like `top`. // as this guarantees that we see the actual rss reflected in tools like `top`.
#if 0 && defined(MADV_FREE) #if 0 && defined(MADV_FREE)
static _Atomic(size_t) advice = MI_ATOMIC_VAR_INIT(MADV_FREE); static _Atomic(size_t) advice = MI_ATOMIC_VAR_INIT(MADV_FREE);
int oadvice = (int)mi_atomic_load_relaxed(&advice); int oadvice = (int)mi_atomic_load_relaxed(&advice);