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authorLars Ellenberg <lars.ellenberg@linbit.com>2011-02-23 12:39:46 +0100
committerPhilipp Reisner <philipp.reisner@linbit.com>2012-05-09 15:17:02 +0200
commit4281808fb3580c381a23cceb0a29ced92d570a5f (patch)
treeb561a60dc382305bba499ae0e12c6e0573a3df06 /drivers/block
parent0e8488ade26b4b16a9745aa15ecb88c3fb1cb953 (diff)
downloadblackbird-op-linux-4281808fb3580c381a23cceb0a29ced92d570a5f.tar.gz
blackbird-op-linux-4281808fb3580c381a23cceb0a29ced92d570a5f.zip
drbd: add page pool to be used for meta data IO
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/drbd/drbd_int.h23
-rw-r--r--drivers/block/drbd/drbd_main.c9
2 files changed, 31 insertions, 1 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 6586053429b4..685ed4cca173 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1496,11 +1496,32 @@ 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 struct drbd_conf *drbd_new_device(unsigned int minor);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index d830116781f9..ed264c92c3af 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -139,6 +139,7 @@ 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.
@@ -3264,6 +3265,8 @@ 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)
@@ -3277,6 +3280,7 @@ 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;
@@ -3300,6 +3304,7 @@ 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(
@@ -3323,6 +3328,10 @@ 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)
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