consistent commit order
@@ -704,8 +704,7 @@ static bool mi_os_commitx(void* addr, size_t size, bool commit, bool conservativ
#if defined(_WIN32)
if (commit) {
- // if the memory was already committed, the call succeeds but it is not zero'd
- // *is_zero = true;
+ // *is_zero = true; // note: if the memory was already committed, the call succeeds but the memory is not zero'd
void* p = VirtualAlloc(start, csize, MEM_COMMIT, PAGE_READWRITE);
err = (p == start ? 0 : GetLastError());
}
@@ -717,22 +716,27 @@ static bool mi_os_commitx(void* addr, size_t size, bool commit, bool conservativ
// WebAssembly guests can't control memory protection
#elif defined(MAP_FIXED) && !defined(__APPLE__)
// Linux
- if (!commit) {
+ if (commit) {
+ // commit: just change the protection
+ err = mprotect(start, csize, (PROT_READ | PROT_WRITE));
+ if (err != 0) { err = errno; }
+ }
+ else {
// 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 {
- // commit: just change the protection
+ #else
+ // macOSX and others.
+ if (commit) {
+ // commit: ensure we can access the area
err = mprotect(start, csize, (PROT_READ | PROT_WRITE));
if (err != 0) { err = errno; }
}
- #else
- // MacOS and others.
- if (!commit) {
+ else {
#if defined(MADV_DONTNEED)
- // decommit: use MADV_DONTNEED as it decrease rss immediately (unlike MADV_FREE)
+ // decommit: use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE)
err = madvise(start, csize, MADV_DONTNEED);
#else
// decommit: just disable access
@@ -740,11 +744,6 @@ static bool mi_os_commitx(void* addr, size_t size, bool commit, bool conservativ
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);
