From 95402b3829010fe1e208f44e4a158ccade88969a Mon Sep 17 00:00:00 2001 From: Gautham R Shenoy Date: Fri, 25 Jan 2008 21:08:02 +0100 Subject: cpu-hotplug: replace per-subsystem mutexes with get_online_cpus() This patch converts the known per-subsystem mutexes to get_online_cpus put_online_cpus. It also eliminates the CPU_LOCK_ACQUIRE and CPU_LOCK_RELEASE hotplug notification events. Signed-off-by: Gautham R Shenoy Signed-off-by: Ingo Molnar --- mm/slab.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'mm') diff --git a/mm/slab.c b/mm/slab.c index ff31261fd24f..40c00dacbe4b 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -730,8 +730,7 @@ static inline void init_lock_keys(void) #endif /* - * 1. Guard access to the cache-chain. - * 2. Protect sanity of cpu_online_map against cpu hotplug events + * Guard access to the cache-chain. */ static DEFINE_MUTEX(cache_chain_mutex); static struct list_head cache_chain; @@ -1331,12 +1330,11 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb, int err = 0; switch (action) { - case CPU_LOCK_ACQUIRE: - mutex_lock(&cache_chain_mutex); - break; case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: + mutex_lock(&cache_chain_mutex); err = cpuup_prepare(cpu); + mutex_unlock(&cache_chain_mutex); break; case CPU_ONLINE: case CPU_ONLINE_FROZEN: @@ -1373,9 +1371,8 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb, #endif case CPU_UP_CANCELED: case CPU_UP_CANCELED_FROZEN: + mutex_lock(&cache_chain_mutex); cpuup_canceled(cpu); - break; - case CPU_LOCK_RELEASE: mutex_unlock(&cache_chain_mutex); break; } @@ -2170,6 +2167,7 @@ kmem_cache_create (const char *name, size_t size, size_t align, * We use cache_chain_mutex to ensure a consistent view of * cpu_online_map as well. Please see cpuup_callback */ + get_online_cpus(); mutex_lock(&cache_chain_mutex); list_for_each_entry(pc, &cache_chain, next) { @@ -2396,6 +2394,7 @@ oops: panic("kmem_cache_create(): failed to create slab `%s'\n", name); mutex_unlock(&cache_chain_mutex); + put_online_cpus(); return cachep; } EXPORT_SYMBOL(kmem_cache_create); @@ -2547,9 +2546,11 @@ int kmem_cache_shrink(struct kmem_cache *cachep) int ret; BUG_ON(!cachep || in_interrupt()); + get_online_cpus(); mutex_lock(&cache_chain_mutex); ret = __cache_shrink(cachep); mutex_unlock(&cache_chain_mutex); + put_online_cpus(); return ret; } EXPORT_SYMBOL(kmem_cache_shrink); @@ -2575,6 +2576,7 @@ void kmem_cache_destroy(struct kmem_cache *cachep) BUG_ON(!cachep || in_interrupt()); /* Find the cache in the chain of caches. */ + get_online_cpus(); mutex_lock(&cache_chain_mutex); /* * the chain is never empty, cache_cache is never destroyed @@ -2584,6 +2586,7 @@ void kmem_cache_destroy(struct kmem_cache *cachep) slab_error(cachep, "Can't free all objects"); list_add(&cachep->next, &cache_chain); mutex_unlock(&cache_chain_mutex); + put_online_cpus(); return; } @@ -2592,6 +2595,7 @@ void kmem_cache_destroy(struct kmem_cache *cachep) __kmem_cache_destroy(cachep); mutex_unlock(&cache_chain_mutex); + put_online_cpus(); } EXPORT_SYMBOL(kmem_cache_destroy); -- cgit v1.2.1