link DiscardVirtualMemory dynamically as it is not supported on every windows
@@ -82,8 +82,11 @@ static size_t mi_os_good_alloc_size(size_t size, size_t alignment) {
#if defined(_WIN32)
// We use VirtualAlloc2 for aligned allocation, but it is only supported on Windows 10 and Windows Server 2016.
// So, we need to look it up dynamically to run on older systems. (use __stdcall for 32-bit compatibility)
-typedef PVOID(__stdcall *VirtualAlloc2Ptr)(HANDLE, PVOID, SIZE_T, ULONG, ULONG, MEM_EXTENDED_PARAMETER*, ULONG);
-static VirtualAlloc2Ptr pVirtualAlloc2 = NULL;
+// Same for DiscardVirtualMemory
+typedef PVOID(__stdcall *PVirtualAlloc2)(HANDLE, PVOID, SIZE_T, ULONG, ULONG, MEM_EXTENDED_PARAMETER*, ULONG);
+typedef DWORD(__stdcall *PDiscardVirtualMemory)(PVOID,SIZE_T);
+static PVirtualAlloc2 pVirtualAlloc2 = NULL;
+static PDiscardVirtualMemory pDiscardVirtualMemory = NULL;
void _mi_os_init(void) {
// get the page size
@@ -95,8 +98,10 @@ void _mi_os_init(void) {
HINSTANCE hDll;
hDll = LoadLibrary(TEXT("kernelbase.dll"));
if (hDll != NULL) {
- // use VirtualAlloc2FromApp as it is available to Windows store apps
- pVirtualAlloc2 = (VirtualAlloc2Ptr)GetProcAddress(hDll, "VirtualAlloc2FromApp");
+ // use VirtualAlloc2FromApp if possible as it is available to Windows store apps
+ pVirtualAlloc2 = (PVirtualAlloc2)GetProcAddress(hDll, "VirtualAlloc2FromApp");
+ if (pVirtualAlloc2==NULL) pVirtualAlloc2 = (PVirtualAlloc2)GetProcAddress(hDll, "VirtualAlloc2");
+ pDiscardVirtualMemory = (PDiscardVirtualMemory)GetProcAddress(hDll, "DiscardVirtualMemory");
FreeLibrary(hDll);
}
// Try to see if large OS pages are supported
@@ -460,22 +465,16 @@ static bool mi_os_resetx(void* addr, size_t size, bool reset, mi_stats_t* stats)
#if defined(_WIN32)
// Testing shows that for us (on `malloc-large`) MEM_RESET is 2x faster than DiscardVirtualMemory
// (but this is for an access pattern that immediately reuses the memory)
- if (mi_option_is_enabled(mi_option_reset_discards)) {
- DWORD ok = DiscardVirtualMemory(start, csize);
- mi_assert_internal(ok == 0);
- if (ok != 0) return false;
+ if (mi_option_is_enabled(mi_option_reset_discards) && pDiscardVirtualMemory != NULL) {
+ DWORD ok = (*pDiscardVirtualMemory)(start, csize);
+ mi_assert_internal(ok == ERROR_SUCCESS);
+ if (ok != ERROR_SUCCESS) return false;
}
else {
void* p = VirtualAlloc(start, csize, MEM_RESET, PAGE_READWRITE);
mi_assert_internal(p == start);
if (p != start) return false;
}
- /*
- // VirtualUnlock removes the memory eagerly from the current working set (which MEM_RESET does lazily on demand)
- // TODO: put this behind an option?
- DWORD ok = VirtualUnlock(start, csize);
- if (ok != 0) return false;
- */
#else
#if defined(MADV_FREE)
static int advice = MADV_FREE;
