diff options
| -rw-r--r-- | mm/mempool.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/mm/mempool.c b/mm/mempool.c index 7924f4f..07c383d 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -310,25 +310,36 @@ EXPORT_SYMBOL(mempool_resize); * returns NULL. Note that due to preallocation, this function * *never* fails when called from process contexts. (it might * fail if called from an IRQ context.) - * Note: using __GFP_ZERO is not supported. + * Note: neither __GFP_NOMEMALLOC nor __GFP_ZERO are supported. */ -void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask) +void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) { void *element; unsigned long flags; wait_queue_t wait; gfp_t gfp_temp; + /* If oom killed, memory reserves are essential to prevent livelock */ + VM_WARN_ON_ONCE(gfp_mask & __GFP_NOMEMALLOC); + /* No element size to zero on allocation */ VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO); + might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM); - gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */ gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */ gfp_mask |= __GFP_NOWARN; /* failures are OK */ gfp_temp = gfp_mask & ~(__GFP_DIRECT_RECLAIM|__GFP_IO); repeat_alloc: + if (likely(pool->curr_nr)) { + /* + * Don't allocate from emergency reserves if there are + * elements available. This check is racy, but it will + * be rechecked each loop. + */ + gfp_temp |= __GFP_NOMEMALLOC; + } element = pool->alloc(gfp_temp, pool->pool_data); if (likely(element != NULL)) @@ -352,11 +363,12 @@ repeat_alloc: * We use gfp mask w/o direct reclaim or IO for the first round. If * alloc failed with that and @pool was empty, retry immediately. */ - if (gfp_temp != gfp_mask) { + if ((gfp_temp & ~__GFP_NOMEMALLOC) != gfp_mask) { spin_unlock_irqrestore(&pool->lock, flags); gfp_temp = gfp_mask; goto repeat_alloc; } + gfp_temp = gfp_mask; /* We must not sleep if !__GFP_DIRECT_RECLAIM */ if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { |
