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drbd: add page pool to be used for meta data IO
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Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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Lars Ellenberg authored and Philipp Reisner committed May 9, 2012
1 parent 0e8488a commit 4281808
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Showing 2 changed files with 31 additions and 1 deletion.
23 changes: 22 additions & 1 deletion drivers/block/drbd/drbd_int.h
Original file line number Diff line number Diff line change
Expand Up @@ -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);
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9 changes: 9 additions & 0 deletions drivers/block/drbd/drbd_main.c
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand Down Expand Up @@ -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)
Expand All @@ -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;
Expand All @@ -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(
Expand All @@ -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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