diff options
Diffstat (limited to 'drivers/md/dm-cache-policy.h')
| -rw-r--r-- | drivers/md/dm-cache-policy.h | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h index f50fe36..05db56e 100644 --- a/drivers/md/dm-cache-policy.h +++ b/drivers/md/dm-cache-policy.h @@ -70,6 +70,18 @@ enum policy_operation { }; /* + * When issuing a POLICY_REPLACE the policy needs to make a callback to + * lock the block being demoted. This doesn't need to occur during a + * writeback operation since the block remains in the cache. + */ +struct policy_locker; +typedef int (*policy_lock_fn)(struct policy_locker *l, dm_oblock_t oblock); + +struct policy_locker { + policy_lock_fn fn; +}; + +/* * This is the instruction passed back to the core target. */ struct policy_result { @@ -122,7 +134,8 @@ struct dm_cache_policy { */ int (*map)(struct dm_cache_policy *p, dm_oblock_t oblock, bool can_block, bool can_migrate, bool discarded_oblock, - struct bio *bio, struct policy_result *result); + struct bio *bio, struct policy_locker *locker, + struct policy_result *result); /* * Sometimes we want to see if a block is in the cache, without @@ -165,7 +178,9 @@ struct dm_cache_policy { int (*remove_cblock)(struct dm_cache_policy *p, dm_cblock_t cblock); /* - * Provide a dirty block to be written back by the core target. + * Provide a dirty block to be written back by the core target. If + * critical_only is set then the policy should only provide work if + * it urgently needs it. * * Returns: * @@ -173,7 +188,8 @@ struct dm_cache_policy { * * -ENODATA: no dirty blocks available */ - int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock); + int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock, + bool critical_only); /* * How full is the cache? @@ -184,16 +200,16 @@ struct dm_cache_policy { * Because of where we sit in the block layer, we can be asked to * map a lot of little bios that are all in the same block (no * queue merging has occurred). To stop the policy being fooled by - * these the core target sends regular tick() calls to the policy. + * these, the core target sends regular tick() calls to the policy. * The policy should only count an entry as hit once per tick. */ - void (*tick)(struct dm_cache_policy *p); + void (*tick)(struct dm_cache_policy *p, bool can_block); /* * Configuration. */ - int (*emit_config_values)(struct dm_cache_policy *p, - char *result, unsigned maxlen); + int (*emit_config_values)(struct dm_cache_policy *p, char *result, + unsigned maxlen, ssize_t *sz_ptr); int (*set_config_value)(struct dm_cache_policy *p, const char *key, const char *value); |
