https://github.com/python/cpython/commit/b852236b26e0464c8c4ba3189846b128c9a5cdf6
commit: b852236b26e0464c8c4ba3189846b128c9a5cdf6
branch: main
author: Ken Jin <[email protected]>
committer: Fidget-Spinner <[email protected]>
date: 2026-01-09T16:56:19Z
summary:
gh-143421: Lazily allocate tracer code and opt buffers (GH-143597)
files:
M Include/internal/pycore_optimizer_types.h
M Include/internal/pycore_tstate.h
M Python/optimizer.c
M Python/optimizer_analysis.c
M Python/pystate.c
diff --git a/Include/internal/pycore_optimizer_types.h
b/Include/internal/pycore_optimizer_types.h
index de8e50921e3311..0a193268c4d618 100644
--- a/Include/internal/pycore_optimizer_types.h
+++ b/Include/internal/pycore_optimizer_types.h
@@ -10,8 +10,8 @@ extern "C" {
#include "pycore_uop.h" // UOP_MAX_TRACE_LENGTH
-// Holds locals, stack, locals, stack ... co_consts (in that order)
-#define MAX_ABSTRACT_INTERP_SIZE 4096
+// Holds locals, stack, locals, stack ... (in that order)
+#define MAX_ABSTRACT_INTERP_SIZE 512
#define TY_ARENA_SIZE (UOP_MAX_TRACE_LENGTH * 5)
diff --git a/Include/internal/pycore_tstate.h b/Include/internal/pycore_tstate.h
index 81cabb4dca47e4..262051c015ab5e 100644
--- a/Include/internal/pycore_tstate.h
+++ b/Include/internal/pycore_tstate.h
@@ -56,8 +56,8 @@ typedef struct _PyJitTracerState {
_PyJitTracerInitialState initial_state;
_PyJitTracerPreviousState prev_state;
_PyJitTracerTranslatorState translator_state;
- JitOptContext opt_context;
- _PyUOpInstruction code_buffer[UOP_MAX_TRACE_LENGTH];
+ JitOptContext *opt_context;
+ _PyUOpInstruction *code_buffer;
} _PyJitTracerState;
#endif
diff --git a/Python/optimizer.c b/Python/optimizer.c
index 73617f6ca26425..a0d72454aa3ea5 100644
--- a/Python/optimizer.c
+++ b/Python/optimizer.c
@@ -1025,6 +1025,13 @@ _PyJit_TryInitializeTracing(
if (oparg > 0xFFFF) {
return 0;
}
+ if (_tstate->jit_tracer_state.code_buffer == NULL) {
+ _tstate->jit_tracer_state.code_buffer = (_PyUOpInstruction
*)_PyObject_VirtualAlloc(UOP_BUFFER_SIZE);
+ if (_tstate->jit_tracer_state.code_buffer == NULL) {
+ // Don't error, just go to next instruction.
+ return 0;
+ }
+ }
PyObject *func = PyStackRef_AsPyObjectBorrow(frame->f_funcobj);
if (func == NULL) {
return 0;
diff --git a/Python/optimizer_analysis.c b/Python/optimizer_analysis.c
index 56d4f9945d6908..d7b81f07d0b86f 100644
--- a/Python/optimizer_analysis.c
+++ b/Python/optimizer_analysis.c
@@ -345,7 +345,15 @@ optimize_uops(
assert(!PyErr_Occurred());
PyFunctionObject *func = tstate->jit_tracer_state.initial_state.func;
- JitOptContext *ctx = &tstate->jit_tracer_state.opt_context;
+ JitOptContext *ctx = tstate->jit_tracer_state.opt_context;
+ if (ctx == NULL) {
+ ctx = (JitOptContext *)_PyObject_VirtualAlloc(sizeof(JitOptContext));
+ if (ctx == NULL) {
+ // Don't error, just bail.
+ return 0;
+ }
+ tstate->jit_tracer_state.opt_context = ctx;
+ }
uint32_t opcode = UINT16_MAX;
// Make sure that watchers are set up
diff --git a/Python/pystate.c b/Python/pystate.c
index 74507efa5b4cf3..a186ac58abadec 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -1553,6 +1553,8 @@ init_threadstate(_PyThreadStateImpl *_tstate,
init_policy(&_tstate->policy.jit.side_exit_initial_backoff,
"PYTHON_JIT_SIDE_EXIT_INITIAL_BACKOFF",
SIDE_EXIT_INITIAL_BACKOFF, 0, MAX_BACKOFF);
+ _tstate->jit_tracer_state.code_buffer = NULL;
+ _tstate->jit_tracer_state.opt_context = NULL;
#endif
tstate->delete_later = NULL;
@@ -1867,6 +1869,18 @@ tstate_delete_common(PyThreadState *tstate, int
release_gil)
assert(tstate_impl->refcounts.values == NULL);
#endif
+#if _Py_TIER2
+ _PyThreadStateImpl *_tstate = (_PyThreadStateImpl *)tstate;
+ if (_tstate->jit_tracer_state.code_buffer != NULL) {
+ _PyObject_VirtualFree(_tstate->jit_tracer_state.code_buffer,
UOP_BUFFER_SIZE);
+ _tstate->jit_tracer_state.code_buffer = NULL;
+ }
+ if (_tstate->jit_tracer_state.opt_context != NULL) {
+ _PyObject_VirtualFree(_tstate->jit_tracer_state.opt_context,
sizeof(JitOptContext));
+ _tstate->jit_tracer_state.opt_context = NULL;
+ }
+#endif
+
HEAD_UNLOCK(runtime);
// XXX Unbind in PyThreadState_Clear(), or earlier
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