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GH-126195: Use M1 JIT memory protection APIs (GH-126196)

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Diego Russo 2024-11-12 01:20:10 +00:00 committed by GitHub
parent 494360afd0
commit c45be8aa71
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2 changed files with 17 additions and 2 deletions
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1
Misc/NEWS.d/next/Core_and_Builtins/2024-10-30-18-16-10.gh-issue-126195.6ezBpr.rst Normal file
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@ -0,0 +1 @@
Improve JIT performance by 1.4% on macOS Apple Silicon by using platform-specific memory protection APIs. Patch by Diego Russo.

18
Python/jit.c
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@ -58,7 +58,12 @@ jit_alloc(size_t size)
int failed = memory == NULL;
#else
int flags = MAP_ANONYMOUS | MAP_PRIVATE;
unsigned char *memory = mmap(NULL, size, PROT_READ | PROT_WRITE, flags, -1, 0);
int prot = PROT_READ | PROT_WRITE;
# ifdef MAP_JIT
flags |= MAP_JIT;
prot |= PROT_EXEC;
# endif
unsigned char *memory = mmap(NULL, size, prot, flags, -1, 0);
int failed = memory == MAP_FAILED;
#endif
if (failed) {
@ -102,8 +107,11 @@ mark_executable(unsigned char *memory, size_t size)
int old;
int failed = !VirtualProtect(memory, size, PAGE_EXECUTE_READ, &old);
#else
int failed = 0;
__builtin___clear_cache((char *)memory, (char *)memory + size);
int failed = mprotect(memory, size, PROT_EXEC | PROT_READ);
#ifndef MAP_JIT
failed = mprotect(memory, size, PROT_EXEC | PROT_READ);
#endif
#endif
if (failed) {
jit_error("unable to protect executable memory");
@ -499,6 +507,9 @@ _PyJIT_Compile(_PyExecutorObject *executor, const _PyUOpInstruction trace[], siz
if (memory == NULL) {
return -1;
}
#ifdef MAP_JIT
pthread_jit_write_protect_np(0);
#endif
// Update the offsets of each instruction:
for (size_t i = 0; i < length; i++) {
state.instruction_starts[i] += (uintptr_t)memory;
@ -529,6 +540,9 @@ _PyJIT_Compile(_PyExecutorObject *executor, const _PyUOpInstruction trace[], siz
data += group->data_size;
assert(code == memory + code_size);
assert(data == memory + code_size + data_size);
#ifdef MAP_JIT
pthread_jit_write_protect_np(1);
#endif
if (mark_executable(memory, total_size)) {
jit_free(memory, total_size);
return -1;