diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index 783526ab7b20a91d60fc836e51d28bd48f8d2762..2444a1683475488ee9176c1b857d9f300e7f3faf 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -1463,11 +1463,32 @@ extern struct kmem_cache *drbd_al_ext_cache; /* activity log extents */ extern mempool_t *drbd_request_mempool; extern mempool_t *drbd_ee_mempool; -extern struct page *drbd_pp_pool; /* drbd's page pool */ +/* drbd's page pool, used to buffer data received from the peer, + * or data requested by the peer. + * + * This does not have an emergency reserve. + * + * When allocating from this pool, it first takes pages from the pool. + * Only if the pool is depleted will try to allocate from the system. + * + * The assumption is that pages taken from this pool will be processed, + * and given back, "quickly", and then can be recycled, so we can avoid + * frequent calls to alloc_page(), and still will be able to make progress even + * under memory pressure. + */ +extern struct page *drbd_pp_pool; extern spinlock_t drbd_pp_lock; extern int drbd_pp_vacant; extern wait_queue_head_t drbd_pp_wait; +/* We also need a standard (emergency-reserve backed) page pool + * for meta data IO (activity log, bitmap). + * We can keep it global, as long as it is used as "N pages at a time". + * 128 should be plenty, currently we probably can get away with as few as 1. + */ +#define DRBD_MIN_POOL_PAGES 128 +extern mempool_t *drbd_md_io_page_pool; + extern rwlock_t global_state_lock; extern int conn_lowest_minor(struct drbd_tconn *tconn); diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 12c9a704ea0131d48a3ae915306a44c7f767246b..5f4c95905d5e25364a3f33072e0a63de915f10c5 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -129,6 +129,7 @@ struct kmem_cache *drbd_bm_ext_cache; /* bitmap extents */ struct kmem_cache *drbd_al_ext_cache; /* activity log extents */ mempool_t *drbd_request_mempool; mempool_t *drbd_ee_mempool; +mempool_t *drbd_md_io_page_pool; /* I do not use a standard mempool, because: 1) I want to hand out the pre-allocated objects first. @@ -1952,6 +1953,8 @@ static void drbd_destroy_mempools(void) /* D_ASSERT(atomic_read(&drbd_pp_vacant)==0); */ + if (drbd_md_io_page_pool) + mempool_destroy(drbd_md_io_page_pool); if (drbd_ee_mempool) mempool_destroy(drbd_ee_mempool); if (drbd_request_mempool) @@ -1965,6 +1968,7 @@ static void drbd_destroy_mempools(void) if (drbd_al_ext_cache) kmem_cache_destroy(drbd_al_ext_cache); + drbd_md_io_page_pool = NULL; drbd_ee_mempool = NULL; drbd_request_mempool = NULL; drbd_ee_cache = NULL; @@ -1988,6 +1992,7 @@ static int drbd_create_mempools(void) drbd_bm_ext_cache = NULL; drbd_al_ext_cache = NULL; drbd_pp_pool = NULL; + drbd_md_io_page_pool = NULL; /* caches */ drbd_request_cache = kmem_cache_create( @@ -2011,6 +2016,10 @@ static int drbd_create_mempools(void) goto Enomem; /* mempools */ + drbd_md_io_page_pool = mempool_create_page_pool(DRBD_MIN_POOL_PAGES, 0); + if (drbd_md_io_page_pool == NULL) + goto Enomem; + drbd_request_mempool = mempool_create(number, mempool_alloc_slab, mempool_free_slab, drbd_request_cache); if (drbd_request_mempool == NULL)