diff options
| -rw-r--r-- | mm/vmalloc.c | 37 |
1 files changed, 20 insertions, 17 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index fad6d1d732b2..90517b4b21ef 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1077,31 +1077,34 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, retry: /* - * Preload this CPU with one extra vmap_area object to ensure - * that we have it available when fit type of free area is - * NE_FIT_TYPE. + * Preload this CPU with one extra vmap_area object. It is used + * when fit type of free area is NE_FIT_TYPE. Please note, it + * does not guarantee that an allocation occurs on a CPU that + * is preloaded, instead we minimize the case when it is not. + * It can happen because of cpu migration, because there is a + * race until the below spinlock is taken. * * The preload is done in non-atomic context, thus it allows us * to use more permissive allocation masks to be more stable under - * low memory condition and high memory pressure. + * low memory condition and high memory pressure. In rare case, + * if not preloaded, GFP_NOWAIT is used. * - * Even if it fails we do not really care about that. Just proceed - * as it is. "overflow" path will refill the cache we allocate from. + * Set "pva" to NULL here, because of "retry" path. */ - preempt_disable(); - if (!__this_cpu_read(ne_fit_preload_node)) { - preempt_enable(); - pva = kmem_cache_alloc_node(vmap_area_cachep, GFP_KERNEL, node); - preempt_disable(); + pva = NULL; - if (__this_cpu_cmpxchg(ne_fit_preload_node, NULL, pva)) { - if (pva) - kmem_cache_free(vmap_area_cachep, pva); - } - } + if (!this_cpu_read(ne_fit_preload_node)) + /* + * Even if it fails we do not really care about that. + * Just proceed as it is. If needed "overflow" path + * will refill the cache we allocate from. + */ + pva = kmem_cache_alloc_node(vmap_area_cachep, GFP_KERNEL, node); spin_lock(&vmap_area_lock); - preempt_enable(); + + if (pva && __this_cpu_cmpxchg(ne_fit_preload_node, NULL, pva)) + kmem_cache_free(vmap_area_cachep, pva); /* * If an allocation fails, the "vend" address is |