From 4e781b498ee5008ede91362d91404a362e7a46b3 Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Thu, 15 Sep 2016 09:23:46 -0400 Subject: dm cache: speed up writing of the hint array It's far quicker to always delete the hint array and recreate with dm_array_new() because we avoid the copying caused by mutation. Also simplifies the policy interface, replacing the walk_hints() with the simpler get_hint(). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- drivers/md/dm-cache-metadata.c | 80 ++++++++++++----------------------- drivers/md/dm-cache-policy-cleaner.c | 2 +- drivers/md/dm-cache-policy-internal.h | 6 +-- drivers/md/dm-cache-policy-smq.c | 38 +++-------------- drivers/md/dm-cache-policy.h | 10 ++--- 5 files changed, 42 insertions(+), 94 deletions(-) (limited to 'drivers/md') diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c index 3970cda10080..a60f10a0ee0a 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -1368,10 +1368,24 @@ int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, /*----------------------------------------------------------------*/ -static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) +static int get_hint(uint32_t index, void *value_le, void *context) +{ + uint32_t value; + struct dm_cache_policy *policy = context; + + value = policy_get_hint(policy, to_cblock(index)); + *((__le32 *) value_le) = cpu_to_le32(value); + + return 0; +} + +/* + * It's quicker to always delete the hint array, and recreate with + * dm_array_new(). + */ +static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) { int r; - __le32 value; size_t hint_size; const char *policy_name = dm_cache_policy_get_name(policy); const unsigned *policy_version = dm_cache_policy_get_version(policy); @@ -1380,63 +1394,23 @@ static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *po (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) return -EINVAL; - if (!policy_unchanged(cmd, policy)) { - strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); - memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); + strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); + memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); - hint_size = dm_cache_policy_get_hint_size(policy); - if (!hint_size) - return 0; /* short-circuit hints initialization */ - cmd->policy_hint_size = hint_size; + hint_size = dm_cache_policy_get_hint_size(policy); + if (!hint_size) + return 0; /* short-circuit hints initialization */ + cmd->policy_hint_size = hint_size; - if (cmd->hint_root) { - r = dm_array_del(&cmd->hint_info, cmd->hint_root); - if (r) - return r; - } - - r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); + if (cmd->hint_root) { + r = dm_array_del(&cmd->hint_info, cmd->hint_root); if (r) return r; - - value = cpu_to_le32(0); - __dm_bless_for_disk(&value); - r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, - from_cblock(cmd->cache_blocks), - &value, &cmd->hint_root); - if (r) - return r; - } - - return 0; -} - -static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint) -{ - struct dm_cache_metadata *cmd = context; - __le32 value = cpu_to_le32(hint); - int r; - - __dm_bless_for_disk(&value); - - r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, - from_cblock(cblock), &value, &cmd->hint_root); - cmd->changed = true; - - return r; -} - -static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) -{ - int r; - - r = begin_hints(cmd, policy); - if (r) { - DMERR("begin_hints failed"); - return r; } - return policy_walk_mappings(policy, save_hint, cmd); + return dm_array_new(&cmd->hint_info, &cmd->hint_root, + from_cblock(cmd->cache_blocks), + get_hint, policy); } int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) diff --git a/drivers/md/dm-cache-policy-cleaner.c b/drivers/md/dm-cache-policy-cleaner.c index 14aaaf059f06..2e8a8f1d8358 100644 --- a/drivers/md/dm-cache-policy-cleaner.c +++ b/drivers/md/dm-cache-policy-cleaner.c @@ -395,7 +395,7 @@ static void init_policy_functions(struct policy *p) p->policy.set_dirty = wb_set_dirty; p->policy.clear_dirty = wb_clear_dirty; p->policy.load_mapping = wb_load_mapping; - p->policy.walk_mappings = NULL; + p->policy.get_hint = NULL; p->policy.remove_mapping = wb_remove_mapping; p->policy.writeback_work = wb_writeback_work; p->policy.force_mapping = wb_force_mapping; diff --git a/drivers/md/dm-cache-policy-internal.h b/drivers/md/dm-cache-policy-internal.h index 2816018faa7f..808ee0e2b2c4 100644 --- a/drivers/md/dm-cache-policy-internal.h +++ b/drivers/md/dm-cache-policy-internal.h @@ -48,10 +48,10 @@ static inline int policy_load_mapping(struct dm_cache_policy *p, return p->load_mapping(p, oblock, cblock, hint, hint_valid); } -static inline int policy_walk_mappings(struct dm_cache_policy *p, - policy_walk_fn fn, void *context) +static inline uint32_t policy_get_hint(struct dm_cache_policy *p, + dm_cblock_t cblock) { - return p->walk_mappings ? p->walk_mappings(p, fn, context) : 0; + return p->get_hint ? p->get_hint(p, cblock) : 0; } static inline int policy_writeback_work(struct dm_cache_policy *p, diff --git a/drivers/md/dm-cache-policy-smq.c b/drivers/md/dm-cache-policy-smq.c index cf48a617a3a4..f3cec4e6333c 100644 --- a/drivers/md/dm-cache-policy-smq.c +++ b/drivers/md/dm-cache-policy-smq.c @@ -1375,41 +1375,15 @@ static int smq_load_mapping(struct dm_cache_policy *p, return 0; } -static int smq_save_hints(struct smq_policy *mq, struct queue *q, - policy_walk_fn fn, void *context) -{ - int r; - unsigned level; - struct entry *e; - - for (level = 0; level < q->nr_levels; level++) - for (e = l_head(q->es, q->qs + level); e; e = l_next(q->es, e)) { - if (!e->sentinel) { - r = fn(context, infer_cblock(mq, e), - e->oblock, e->level); - if (r) - return r; - } - } - - return 0; -} - -static int smq_walk_mappings(struct dm_cache_policy *p, policy_walk_fn fn, - void *context) +static uint32_t smq_get_hint(struct dm_cache_policy *p, dm_cblock_t cblock) { struct smq_policy *mq = to_smq_policy(p); - int r = 0; + struct entry *e = get_entry(&mq->cache_alloc, from_cblock(cblock)); - /* - * We don't need to lock here since this method is only called once - * the IO has stopped. - */ - r = smq_save_hints(mq, &mq->clean, fn, context); - if (!r) - r = smq_save_hints(mq, &mq->dirty, fn, context); + if (!e->allocated) + return 0; - return r; + return e->level; } static void __remove_mapping(struct smq_policy *mq, dm_oblock_t oblock) @@ -1616,7 +1590,7 @@ static void init_policy_functions(struct smq_policy *mq, bool mimic_mq) mq->policy.set_dirty = smq_set_dirty; mq->policy.clear_dirty = smq_clear_dirty; mq->policy.load_mapping = smq_load_mapping; - mq->policy.walk_mappings = smq_walk_mappings; + mq->policy.get_hint = smq_get_hint; mq->policy.remove_mapping = smq_remove_mapping; mq->policy.remove_cblock = smq_remove_cblock; mq->policy.writeback_work = smq_writeback_work; diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h index 05db56eedb6a..aa10b1493f34 100644 --- a/drivers/md/dm-cache-policy.h +++ b/drivers/md/dm-cache-policy.h @@ -90,9 +90,6 @@ struct policy_result { dm_cblock_t cblock; /* POLICY_HIT, POLICY_NEW, POLICY_REPLACE */ }; -typedef int (*policy_walk_fn)(void *context, dm_cblock_t cblock, - dm_oblock_t oblock, uint32_t hint); - /* * The cache policy object. Just a bunch of methods. It is envisaged that * this structure will be embedded in a bigger, policy specific structure @@ -158,8 +155,11 @@ struct dm_cache_policy { int (*load_mapping)(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t cblock, uint32_t hint, bool hint_valid); - int (*walk_mappings)(struct dm_cache_policy *p, policy_walk_fn fn, - void *context); + /* + * Gets the hint for a given cblock. Called in a single threaded + * context. So no locking required. + */ + uint32_t (*get_hint)(struct dm_cache_policy *p, dm_cblock_t cblock); /* * Override functions used on the error paths of the core target. -- cgit v1.2.3-59-g8ed1b