use most performant reset on Linux (MADV_FREE) and Windows (MEM_RESET) as we use the precise decommit by default for purging anyways

This commit is contained in:
daanx 2023-04-24 08:56:42 -07:00
parent 7e4e545060
commit 0bb5cecbc2
2 changed files with 7 additions and 5 deletions

View File

@ -391,9 +391,11 @@ int _mi_prim_decommit(void* start, size_t size, bool* needs_recommit) {
}
int _mi_prim_reset(void* start, size_t size) {
// We always use MADV_DONTNEED if possible even if it may be a bit more expensive as MADV_FREE
// as this guarantees that we see the actual rss reflected in tools like `top`.
#if 0 && defined(MADV_FREE)
// We try to use `MADV_FREE` as that is the fastest. A drawback though is that it
// will not reduce the `rss` stats in tools like `top` even though the memory is available
// to other processes. With the default `MIMALLOC_PURGE_DECOMMITS=1` we ensure that by
// default `MADV_DONTNEED` is used though.
#if defined(MADV_FREE)
static _Atomic(size_t) advice = MI_ATOMIC_VAR_INIT(MADV_FREE);
int oadvice = (int)mi_atomic_load_relaxed(&advice);
int err;

View File

@ -285,9 +285,9 @@ int _mi_prim_decommit(void* addr, size_t size, bool* needs_recommit) {
int _mi_prim_reset(void* addr, size_t size) {
void* p = VirtualAlloc(addr, size, MEM_RESET, PAGE_READWRITE);
mi_assert_internal(p == addr);
#if 1
#if 0
if (p != NULL) {
VirtualUnlock(addr,size); // VirtualUnlock after MEM_RESET removes the memory from the working set
VirtualUnlock(addr,size); // VirtualUnlock after MEM_RESET removes the memory directly from the working set
}
#endif
return (p != NULL ? 0 : (int)GetLastError());