diff options
Diffstat (limited to 'drivers/block/drbd/drbd_int.h')
| -rw-r--r-- | drivers/block/drbd/drbd_int.h | 23 |
1 files changed, 22 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); |