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remove vestigal locking from obmalloc (GH-5805)

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obmalloc has (empty) macros for locking in the allocator. These aren't needed in CPython; we rely on the GIL.
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Benjamin Peterson 2018-02-24 11:59:10 -08:00 • committed by GitHub
parent acd7163c0a
commit b18f8bc1a7
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1 changed files with 0 additions and 39 deletions
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39
Objects/obmalloc.c
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@ -849,30 +849,6 @@ static int running_on_valgrind = -1;
/*==========================================================================*/ /*==========================================================================*/
/*
* Locking
*
* To reduce lock contention, it would probably be better to refine the
* crude function locking with per size class locking. I'm not positive
* however, whether it's worth switching to such locking policy because
* of the performance penalty it might introduce.
*
* The following macros describe the simplest (should also be the fastest)
* lock object on a particular platform and the init/fini/lock/unlock
* operations on it. The locks defined here are not expected to be recursive
* because it is assumed that they will always be called in the order:
* INIT, [LOCK, UNLOCK]*, FINI.
*/
/*
* Python's threads are serialized, so object malloc locking is disabled.
*/
#define SIMPLELOCK_DECL(lock) /* simple lock declaration */
#define SIMPLELOCK_INIT(lock) /* allocate (if needed) and initialize */
#define SIMPLELOCK_FINI(lock) /* free/destroy an existing lock */
#define SIMPLELOCK_LOCK(lock) /* acquire released lock */
#define SIMPLELOCK_UNLOCK(lock) /* release acquired lock */
/* When you say memory, my mind reasons in terms of (pointers to) blocks */ /* When you say memory, my mind reasons in terms of (pointers to) blocks */
typedef uint8_t block; typedef uint8_t block;
@ -944,15 +920,6 @@ struct arena_object {
/*==========================================================================*/ /*==========================================================================*/
/*
* This malloc lock
*/
SIMPLELOCK_DECL(_malloc_lock)
#define LOCK() SIMPLELOCK_LOCK(_malloc_lock)
#define UNLOCK() SIMPLELOCK_UNLOCK(_malloc_lock)
#define LOCK_INIT() SIMPLELOCK_INIT(_malloc_lock)
#define LOCK_FINI() SIMPLELOCK_FINI(_malloc_lock)
/* /*
* Pool table -- headed, circular, doubly-linked lists of partially used pools. * Pool table -- headed, circular, doubly-linked lists of partially used pools.
@ -1381,7 +1348,6 @@ pymalloc_alloc(void *ctx, void **ptr_p, size_t nbytes)
return 0; return 0;
} }
LOCK();
/* /*
* Most frequent paths first * Most frequent paths first
*/ */
@ -1537,13 +1503,11 @@ pymalloc_alloc(void *ctx, void **ptr_p, size_t nbytes)
goto init_pool; goto init_pool;
success: success:
UNLOCK();
assert(bp != NULL); assert(bp != NULL);
*ptr_p = (void *)bp; *ptr_p = (void *)bp;
return 1; return 1;
failed: failed:
UNLOCK();
return 0; return 0;
} }
@ -1612,8 +1576,6 @@ pymalloc_free(void *ctx, void *p)
} }
/* We allocated this address. */ /* We allocated this address. */
LOCK();
/* Link p to the start of the pool's freeblock list. Since /* Link p to the start of the pool's freeblock list. Since
* the pool had at least the p block outstanding, the pool * the pool had at least the p block outstanding, the pool
* wasn't empty (so it's already in a usedpools[] list, or * wasn't empty (so it's already in a usedpools[] list, or
@ -1798,7 +1760,6 @@ pymalloc_free(void *ctx, void *p)
goto success; goto success;
success: success:
UNLOCK();
return 1; return 1;
} }