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Use back-off strategy when allocating virtual memory.

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This commit is contained in:
Christoffer Lerno
2024-08-02 15:45:16 +02:00
parent 8498cb6258
commit f8f116109a
1 changed files with 19 additions and 3 deletions
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22
src/utils/vmem.c
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@@ -7,6 +7,8 @@
#if PLATFORM_POSIX
#include <sys/mman.h>
#include <errno.h>
#endif
#if PLATFORM_WINDOWS
@@ -17,7 +19,6 @@
static inline void mmap_init(Vmem *vmem, size_t size)
{
vmem->size = size;
#if PLATFORM_WINDOWS
void* ptr = VirtualAlloc(0, size, MEM_RESERVE, PAGE_NOACCESS);
vmem->committed = 0;
@@ -26,14 +27,29 @@ static inline void mmap_init(Vmem *vmem, size_t size)
FATAL_ERROR("Failed to map virtual memory block");
}
#elif PLATFORM_POSIX
void* ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
void* ptr = NULL;
size_t min_size = size / 16;
if (min_size < 1) min_size = size;
while (size >= min_size)
{
ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
// It worked?
if (ptr != MAP_FAILED && ptr) break;
// Did it fail in a non-retriable way?
if (errno != ENOMEM && errno != EOVERFLOW && errno != EAGAIN) break;
// Try a smaller size
size /= 2;
}
// Check if we ended on a failure.
if ((ptr == MAP_FAILED) || !ptr)
{
FATAL_ERROR("Failed to map virtual memory block");
FATAL_ERROR("Failed to map a virtual memory block.");
}
// Otherwise, record the size and we're fine!
#else
FATAL_ERROR("Unsupported platform.");
#endif
vmem->size = size;
vmem->ptr = ptr;
vmem->allocated = 0;
}