Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Tue, 2 Sep 2003 02:51:45 -0500 | From | Mitchell Blank Jr <> | Subject | [PATCH] might_sleep() improvements |
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Andrew - I thought this might be appropriate for -mm kernels.
This patch makes the following improvements to might_sleep():
o Add a "might_sleep_if()" macro for when we might sleep only if some condition is met. I think this is a bit better than the currently used "if (cond) might_sleep();" since it's clearer that the test won't be compiled in if spinlock sleep debugging is turned off. (Obviously gcc is smart enough to omit simple conditions in that case) It also looks cleaner, IMO. Think of it as analogous to BUG()/BUG_ON().
o Add might_sleep checks to skb_share_check() and skb_unshare() which sometimes need to allocate memory.
o Make all architectures call might_sleep() in both down() and down_interruptible(). Before only ppc, ppc64, and i386 did this check. (sh did the check on down() but not down_interruptible())
Patch is versus 2.6.0-test4, hopefully it still applies cleanly.
-Mitch
diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/arch/sparc64/kernel/semaphore.c linux-2.6.0-test4mightsleep/arch/sparc64/kernel/semaphore.c --- linux-2.6.0-test4-VIRGIN/arch/sparc64/kernel/semaphore.c 2003-07-13 20:37:13.000000000 -0700 +++ linux-2.6.0-test4mightsleep/arch/sparc64/kernel/semaphore.c 2003-09-01 13:38:18.000000000 -0700 @@ -110,6 +110,7 @@ void down(struct semaphore *sem) { + might_sleep(); /* This atomically does: * old_val = sem->count; * new_val = sem->count - 1; @@ -219,6 +220,7 @@ { int ret = 0; + might_sleep(); /* This atomically does: * old_val = sem->count; * new_val = sem->count - 1; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-alpha/semaphore.h linux-2.6.0-test4mightsleep/include/asm-alpha/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-alpha/semaphore.h 2003-07-13 20:37:17.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-alpha/semaphore.h 2003-09-01 13:28:36.000000000 -0700 @@ -88,14 +88,18 @@ static inline void __down(struct semaphore *sem) { - long count = atomic_dec_return(&sem->count); + long count; + might_sleep(); + count = atomic_dec_return(&sem->count); if (unlikely(count < 0)) __down_failed(sem); } static inline int __down_interruptible(struct semaphore *sem) { - long count = atomic_dec_return(&sem->count); + long count; + might_sleep(); + count = atomic_dec_return(&sem->count); if (unlikely(count < 0)) return __down_failed_interruptible(sem); return 0; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-arm/semaphore.h linux-2.6.0-test4mightsleep/include/asm-arm/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-arm/semaphore.h 2003-07-13 20:34:31.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-arm/semaphore.h 2003-09-01 13:29:33.000000000 -0700 @@ -88,7 +88,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); __down_op(sem, __down_failed); } @@ -101,7 +101,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); return __down_op_ret(sem, __down_interruptible_failed); } diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-arm26/semaphore.h linux-2.6.0-test4mightsleep/include/asm-arm26/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-arm26/semaphore.h 2003-07-13 20:38:51.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-arm26/semaphore.h 2003-09-01 13:29:04.000000000 -0700 @@ -84,7 +84,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); __down_op(sem, __down_failed); } @@ -97,7 +97,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); return __down_op_ret(sem, __down_interruptible_failed); } diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-cris/semaphore.h linux-2.6.0-test4mightsleep/include/asm-cris/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-cris/semaphore.h 2003-07-13 20:32:42.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-cris/semaphore.h 2003-09-01 13:30:37.000000000 -0700 @@ -79,6 +79,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); /* atomically decrement the semaphores count, and if its negative, we wait */ local_save_flags(flags); @@ -104,6 +105,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); /* atomically decrement the semaphores count, and if its negative, we wait */ local_save_flags(flags); diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-h8300/semaphore.h linux-2.6.0-test4mightsleep/include/asm-h8300/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-h8300/semaphore.h 2003-08-22 13:47:25.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-h8300/semaphore.h 2003-09-01 13:30:59.000000000 -0700 @@ -90,6 +90,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); count = &(sem->count); __asm__ __volatile__( @@ -117,6 +118,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); count = &(sem->count); __asm__ __volatile__( diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-ia64/semaphore.h linux-2.6.0-test4mightsleep/include/asm-ia64/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-ia64/semaphore.h 2003-07-13 20:33:51.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-ia64/semaphore.h 2003-09-01 13:31:25.000000000 -0700 @@ -73,6 +73,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); if (atomic_dec_return(&sem->count) < 0) __down(sem); } @@ -89,6 +90,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); if (atomic_dec_return(&sem->count) < 0) ret = __down_interruptible(sem); return ret; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-m68k/semaphore.h linux-2.6.0-test4mightsleep/include/asm-m68k/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-m68k/semaphore.h 2003-07-13 20:39:22.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-m68k/semaphore.h 2003-09-01 13:32:01.000000000 -0700 @@ -89,7 +89,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); __asm__ __volatile__( "| atomic down operation\n\t" "subql #1,%0@\n\t" @@ -112,7 +112,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); __asm__ __volatile__( "| atomic interruptible down operation\n\t" "subql #1,%1@\n\t" diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-m68knommu/semaphore.h linux-2.6.0-test4mightsleep/include/asm-m68knommu/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-m68knommu/semaphore.h 2003-07-13 20:35:14.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-m68knommu/semaphore.h 2003-09-01 13:31:46.000000000 -0700 @@ -88,7 +88,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); __asm__ __volatile__( "| atomic down operation\n\t" "movel %0, %%a1\n\t" @@ -108,7 +108,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); __asm__ __volatile__( "| atomic down operation\n\t" "movel %1, %%a1\n\t" diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-mips/semaphore.h linux-2.6.0-test4mightsleep/include/asm-mips/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-mips/semaphore.h 2003-07-13 20:33:10.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-mips/semaphore.h 2003-09-01 13:32:26.000000000 -0700 @@ -88,6 +88,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); if (atomic_dec_return(&sem->count) < 0) __down(sem); } @@ -103,6 +104,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); if (atomic_dec_return(&sem->count) < 0) ret = __down_interruptible(sem); return ret; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-parisc/semaphore.h linux-2.6.0-test4mightsleep/include/asm-parisc/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-parisc/semaphore.h 2003-07-13 20:28:54.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-parisc/semaphore.h 2003-09-01 13:32:42.000000000 -0700 @@ -84,7 +84,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); spin_lock_irq(&sem->sentry); if (sem->count > 0) { sem->count--; @@ -100,7 +100,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif - + might_sleep(); spin_lock_irq(&sem->sentry); if (sem->count > 0) { sem->count--; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-s390/semaphore.h linux-2.6.0-test4mightsleep/include/asm-s390/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-s390/semaphore.h 2003-07-13 20:28:53.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-s390/semaphore.h 2003-09-01 13:33:06.000000000 -0700 @@ -60,6 +60,7 @@ static inline void down(struct semaphore * sem) { + might_sleep(); if (atomic_dec_return(&sem->count) < 0) __down(sem); } @@ -68,6 +69,7 @@ { int ret = 0; + might_sleep(); if (atomic_dec_return(&sem->count) < 0) ret = __down_interruptible(sem); return ret; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-sh/semaphore.h linux-2.6.0-test4mightsleep/include/asm-sh/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-sh/semaphore.h 2003-07-13 20:38:51.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-sh/semaphore.h 2003-09-01 13:15:52.000000000 -0700 @@ -107,6 +107,7 @@ CHECK_MAGIC(sem->__magic); #endif + might_sleep(); if (atomic_dec_return(&sem->count) < 0) ret = __down_interruptible(sem); return ret; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-sparc/semaphore.h linux-2.6.0-test4mightsleep/include/asm-sparc/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-sparc/semaphore.h 2003-07-13 20:39:21.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-sparc/semaphore.h 2003-09-01 13:34:21.000000000 -0700 @@ -71,6 +71,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); ptr = &(sem->count.counter); increment = 1; @@ -107,6 +108,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); ptr = &(sem->count.counter); increment = 1; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-v850/semaphore.h linux-2.6.0-test4mightsleep/include/asm-v850/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-v850/semaphore.h 2003-07-13 20:33:12.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-v850/semaphore.h 2003-09-01 13:34:52.000000000 -0700 @@ -57,6 +57,7 @@ extern inline void down (struct semaphore * sem) { + might_sleep(); if (atomic_dec_return (&sem->count) < 0) __down (sem); } @@ -64,6 +65,7 @@ extern inline int down_interruptible (struct semaphore * sem) { int ret = 0; + might_sleep(); if (atomic_dec_return (&sem->count) < 0) ret = __down_interruptible (sem); return ret; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/asm-x86_64/semaphore.h linux-2.6.0-test4mightsleep/include/asm-x86_64/semaphore.h --- linux-2.6.0-test4-VIRGIN/include/asm-x86_64/semaphore.h 2003-07-13 20:28:54.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/asm-x86_64/semaphore.h 2003-09-01 13:35:12.000000000 -0700 @@ -118,6 +118,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); __asm__ __volatile__( "# atomic down operation\n\t" @@ -144,6 +145,7 @@ #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif + might_sleep(); __asm__ __volatile__( "# atomic interruptible down operation\n\t" diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/linux/kernel.h linux-2.6.0-test4mightsleep/include/linux/kernel.h --- linux-2.6.0-test4-VIRGIN/include/linux/kernel.h 2003-07-13 20:28:53.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/linux/kernel.h 2003-09-01 13:07:59.000000000 -0700 @@ -52,8 +52,10 @@ #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP void __might_sleep(char *file, int line); #define might_sleep() __might_sleep(__FILE__, __LINE__) +#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) #else #define might_sleep() do {} while(0) +#define might_sleep_if(cond) do {} while (0) #endif extern struct notifier_block *panic_notifier_list; diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/include/linux/skbuff.h linux-2.6.0-test4mightsleep/include/linux/skbuff.h --- linux-2.6.0-test4-VIRGIN/include/linux/skbuff.h 2003-08-10 05:28:41.000000000 -0700 +++ linux-2.6.0-test4mightsleep/include/linux/skbuff.h 2003-09-01 13:26:55.000000000 -0700 @@ -389,6 +389,7 @@ */ static inline struct sk_buff *skb_share_check(struct sk_buff *skb, int pri) { + might_sleep_if(pri != GFP_ATOMIC); if (skb_shared(skb)) { struct sk_buff *nskb = skb_clone(skb, pri); kfree_skb(skb); @@ -419,6 +420,7 @@ */ static inline struct sk_buff *skb_unshare(struct sk_buff *skb, int pri) { + might_sleep_if(pri != GFP_ATOMIC); if (skb_cloned(skb)) { struct sk_buff *nskb = skb_copy(skb, pri); kfree_skb(skb); /* Free our shared copy */ diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/mm/page_alloc.c linux-2.6.0-test4mightsleep/mm/page_alloc.c --- linux-2.6.0-test4-VIRGIN/mm/page_alloc.c 2003-08-22 13:47:28.000000000 -0700 +++ linux-2.6.0-test4mightsleep/mm/page_alloc.c 2003-09-01 13:16:42.000000000 -0700 @@ -542,8 +542,7 @@ int do_retry; struct reclaim_state reclaim_state; - if (wait) - might_sleep(); + might_sleep_if(wait); cold = 0; if (gfp_mask & __GFP_COLD) diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/mm/rmap.c linux-2.6.0-test4mightsleep/mm/rmap.c --- linux-2.6.0-test4-VIRGIN/mm/rmap.c 2003-07-13 20:38:02.000000000 -0700 +++ linux-2.6.0-test4mightsleep/mm/rmap.c 2003-09-01 13:17:19.000000000 -0700 @@ -503,8 +503,7 @@ struct pte_chain *ret; struct pte_chain **pte_chainp; - if (gfp_flags & __GFP_WAIT) - might_sleep(); + might_sleep_if(gfp_flags & __GFP_WAIT); pte_chainp = &get_cpu_var(local_pte_chain); if (*pte_chainp) { diff -urN -X dontdiff linux-2.6.0-test4-VIRGIN/mm/slab.c linux-2.6.0-test4mightsleep/mm/slab.c --- linux-2.6.0-test4-VIRGIN/mm/slab.c 2003-08-22 13:47:28.000000000 -0700 +++ linux-2.6.0-test4mightsleep/mm/slab.c 2003-09-01 13:17:01.000000000 -0700 @@ -1813,8 +1813,7 @@ static inline void cache_alloc_debugcheck_before(kmem_cache_t *cachep, int flags) { - if (flags & __GFP_WAIT) - might_sleep(); + might_sleep_if(flags & __GFP_WAIT); #if DEBUG kmem_flagcheck(cachep, flags); #endif - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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