diff --git a/src/prim/unix/prim.c b/src/prim/unix/prim.c index a90fa659..ba062520 100644 --- a/src/prim/unix/prim.c +++ b/src/prim/unix/prim.c @@ -430,13 +430,29 @@ int _mi_prim_commit(void* start, size_t size, bool* is_zero) { err = errno; unix_mprotect_hint(err); } + + #if defined(__APPLE__) + // MADV_FREE_REUSABLE is paired with MADV_FREE_REUSE for accounting + // if this memory was not marked as MADV_FREE_REUSABLE, this call is noop + madvise(start, size, MADV_FREE_REUSE); + #endif return err; } int _mi_prim_decommit(void* start, size_t size, bool* needs_recommit) { - int err = 0; - // decommit: use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE) - err = unix_madvise(start, size, MADV_DONTNEED); + #if defined(__APPLE__) + // On Apple platforms there is MADV_FREE_REUSABLE -- it marks memory as RESUABLE to reduce memory pressure. + int err = unix_madvise(start, size, MADV_FREE_REUSABLE); + if (err != 0) // if MADV_FREE_REUSABLE fails - fallback to MADV_DONTNEED + { + // use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE) + err = unix_madvise(start, size, MADV_DONTNEED); + } + #else + // use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE) + int err = unix_madvise(start, size, MADV_DONTNEED); + #endif + #if !MI_DEBUG && MI_SECURE<=2 *needs_recommit = false; #else @@ -454,22 +470,30 @@ int _mi_prim_decommit(void* start, size_t size, bool* needs_recommit) { } int _mi_prim_reset(void* start, size_t size) { + int err = 0; + #if defined(__APPLE__) + // On Apple platforms there is MADV_FREE_REUSABLE -- it marks memory as RESUABLE to reduce memory pressure. + err = unix_madvise(start, size, MADV_FREE_REUSABLE); + if (err == 0) + return 0; + // if this fails - fallback to MADV_FREE/MADV_DONTNEED + #endif + // 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; - while ((err = unix_madvise(start, size, oadvice)) != 0 && errno == EAGAIN) { errno = 0; }; - if (err != 0 && errno == EINVAL && oadvice == MADV_FREE) { - // if MADV_FREE is not supported, fall back to MADV_DONTNEED from now on - mi_atomic_store_release(&advice, (size_t)MADV_DONTNEED); - err = unix_madvise(start, size, MADV_DONTNEED); - } + static _Atomic(size_t) advice = MI_ATOMIC_VAR_INIT(MADV_FREE); + int oadvice = (int)mi_atomic_load_relaxed(&advice); + while ((err = unix_madvise(start, size, oadvice)) != 0 && errno == EAGAIN) { errno = 0; }; + if (err != 0 && errno == EINVAL && oadvice == MADV_FREE) { + // if MADV_FREE is not supported, fall back to MADV_DONTNEED from now on + mi_atomic_store_release(&advice, (size_t)MADV_DONTNEED); + err = unix_madvise(start, size, MADV_DONTNEED); + } #else - int err = unix_madvise(start, size, MADV_DONTNEED); + err = unix_madvise(start, size, MADV_DONTNEED); #endif return err; }