dm cache: simplify deferred set reference count increments
Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Родитель
e5aea7b49f
Коммит
8c081b52c6
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@ -718,6 +718,22 @@ static int bio_triggers_commit(struct cache *cache, struct bio *bio)
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return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
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return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
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}
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}
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/*
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* You must increment the deferred set whilst the prison cell is held. To
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* encourage this, we ask for 'cell' to be passed in.
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*/
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static void inc_ds(struct cache *cache, struct bio *bio,
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struct dm_bio_prison_cell *cell)
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{
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size_t pb_data_size = get_per_bio_data_size(cache);
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struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
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BUG_ON(!cell);
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BUG_ON(pb->all_io_entry);
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pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
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}
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static void issue(struct cache *cache, struct bio *bio)
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static void issue(struct cache *cache, struct bio *bio)
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{
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{
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unsigned long flags;
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unsigned long flags;
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@ -737,6 +753,12 @@ static void issue(struct cache *cache, struct bio *bio)
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spin_unlock_irqrestore(&cache->lock, flags);
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spin_unlock_irqrestore(&cache->lock, flags);
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}
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}
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static void inc_and_issue(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell *cell)
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{
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inc_ds(cache, bio, cell);
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issue(cache, bio);
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}
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static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
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static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
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{
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{
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unsigned long flags;
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unsigned long flags;
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@ -1015,6 +1037,11 @@ static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio)
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dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg);
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dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg);
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remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock);
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remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock);
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/*
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* No need to inc_ds() here, since the cell will be held for the
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* duration of the io.
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*/
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generic_make_request(bio);
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generic_make_request(bio);
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}
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}
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@ -1115,8 +1142,7 @@ static void check_for_quiesced_migrations(struct cache *cache,
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return;
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return;
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INIT_LIST_HEAD(&work);
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INIT_LIST_HEAD(&work);
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if (pb->all_io_entry)
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dm_deferred_entry_dec(pb->all_io_entry, &work);
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dm_deferred_entry_dec(pb->all_io_entry, &work);
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if (!list_empty(&work))
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if (!list_empty(&work))
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queue_quiesced_migrations(cache, &work);
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queue_quiesced_migrations(cache, &work);
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@ -1252,6 +1278,11 @@ static void process_flush_bio(struct cache *cache, struct bio *bio)
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else
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else
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remap_to_cache(cache, bio, 0);
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remap_to_cache(cache, bio, 0);
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/*
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* REQ_FLUSH is not directed at any particular block so we don't
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* need to inc_ds(). REQ_FUA's are split into a write + REQ_FLUSH
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* by dm-core.
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*/
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issue(cache, bio);
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issue(cache, bio);
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}
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}
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@ -1301,15 +1332,6 @@ static void inc_miss_counter(struct cache *cache, struct bio *bio)
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&cache->stats.read_miss : &cache->stats.write_miss);
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&cache->stats.read_miss : &cache->stats.write_miss);
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}
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}
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static void issue_cache_bio(struct cache *cache, struct bio *bio,
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struct per_bio_data *pb,
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dm_oblock_t oblock, dm_cblock_t cblock)
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{
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pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
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remap_to_cache_dirty(cache, bio, oblock, cblock);
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issue(cache, bio);
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}
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static void process_bio(struct cache *cache, struct prealloc *structs,
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static void process_bio(struct cache *cache, struct prealloc *structs,
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struct bio *bio)
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struct bio *bio)
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{
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{
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@ -1318,8 +1340,6 @@ static void process_bio(struct cache *cache, struct prealloc *structs,
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dm_oblock_t block = get_bio_block(cache, bio);
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dm_oblock_t block = get_bio_block(cache, bio);
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struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;
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struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;
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struct policy_result lookup_result;
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struct policy_result lookup_result;
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size_t pb_data_size = get_per_bio_data_size(cache);
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struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
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bool discarded_block = is_discarded_oblock(cache, block);
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bool discarded_block = is_discarded_oblock(cache, block);
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bool passthrough = passthrough_mode(&cache->features);
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bool passthrough = passthrough_mode(&cache->features);
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bool can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache));
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bool can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache));
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@ -1359,9 +1379,8 @@ static void process_bio(struct cache *cache, struct prealloc *structs,
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} else {
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} else {
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/* FIXME: factor out issue_origin() */
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/* FIXME: factor out issue_origin() */
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pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
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remap_to_origin_clear_discard(cache, bio, block);
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remap_to_origin_clear_discard(cache, bio, block);
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issue(cache, bio);
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inc_and_issue(cache, bio, new_ocell);
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}
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}
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} else {
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} else {
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inc_hit_counter(cache, bio);
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inc_hit_counter(cache, bio);
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@ -1369,20 +1388,21 @@ static void process_bio(struct cache *cache, struct prealloc *structs,
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if (bio_data_dir(bio) == WRITE &&
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if (bio_data_dir(bio) == WRITE &&
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writethrough_mode(&cache->features) &&
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writethrough_mode(&cache->features) &&
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!is_dirty(cache, lookup_result.cblock)) {
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!is_dirty(cache, lookup_result.cblock)) {
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pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
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remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
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remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
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issue(cache, bio);
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inc_and_issue(cache, bio, new_ocell);
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} else
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issue_cache_bio(cache, bio, pb, block, lookup_result.cblock);
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} else {
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remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
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inc_and_issue(cache, bio, new_ocell);
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}
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}
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}
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break;
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break;
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case POLICY_MISS:
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case POLICY_MISS:
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inc_miss_counter(cache, bio);
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inc_miss_counter(cache, bio);
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pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
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remap_to_origin_clear_discard(cache, bio, block);
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remap_to_origin_clear_discard(cache, bio, block);
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issue(cache, bio);
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inc_and_issue(cache, bio, new_ocell);
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break;
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break;
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case POLICY_NEW:
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case POLICY_NEW:
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@ -1501,6 +1521,9 @@ static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
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bio_list_init(&cache->deferred_flush_bios);
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bio_list_init(&cache->deferred_flush_bios);
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spin_unlock_irqrestore(&cache->lock, flags);
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spin_unlock_irqrestore(&cache->lock, flags);
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/*
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* These bios have already been through inc_ds()
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*/
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while ((bio = bio_list_pop(&bios)))
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while ((bio = bio_list_pop(&bios)))
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submit_bios ? generic_make_request(bio) : bio_io_error(bio);
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submit_bios ? generic_make_request(bio) : bio_io_error(bio);
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}
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}
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@ -1518,6 +1541,9 @@ static void process_deferred_writethrough_bios(struct cache *cache)
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bio_list_init(&cache->deferred_writethrough_bios);
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bio_list_init(&cache->deferred_writethrough_bios);
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spin_unlock_irqrestore(&cache->lock, flags);
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spin_unlock_irqrestore(&cache->lock, flags);
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/*
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* These bios have already been through inc_ds()
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*/
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while ((bio = bio_list_pop(&bios)))
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while ((bio = bio_list_pop(&bios)))
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generic_make_request(bio);
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generic_make_request(bio);
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}
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}
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@ -2406,16 +2432,13 @@ out:
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return r;
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return r;
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}
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}
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static int cache_map(struct dm_target *ti, struct bio *bio)
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static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell **cell)
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{
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{
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struct cache *cache = ti->private;
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int r;
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int r;
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dm_oblock_t block = get_bio_block(cache, bio);
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dm_oblock_t block = get_bio_block(cache, bio);
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size_t pb_data_size = get_per_bio_data_size(cache);
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size_t pb_data_size = get_per_bio_data_size(cache);
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bool can_migrate = false;
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bool can_migrate = false;
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bool discarded_block;
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bool discarded_block;
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struct dm_bio_prison_cell *cell;
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struct policy_result lookup_result;
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struct policy_result lookup_result;
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struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size);
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struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size);
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@ -2437,15 +2460,15 @@ static int cache_map(struct dm_target *ti, struct bio *bio)
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/*
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/*
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* Check to see if that block is currently migrating.
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* Check to see if that block is currently migrating.
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*/
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*/
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cell = alloc_prison_cell(cache);
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*cell = alloc_prison_cell(cache);
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if (!cell) {
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if (!*cell) {
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defer_bio(cache, bio);
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defer_bio(cache, bio);
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return DM_MAPIO_SUBMITTED;
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return DM_MAPIO_SUBMITTED;
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}
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}
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r = bio_detain(cache, block, bio, cell,
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r = bio_detain(cache, block, bio, *cell,
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(cell_free_fn) free_prison_cell,
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(cell_free_fn) free_prison_cell,
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cache, &cell);
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cache, cell);
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if (r) {
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if (r) {
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if (r < 0)
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if (r < 0)
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defer_bio(cache, bio);
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defer_bio(cache, bio);
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@ -2458,11 +2481,12 @@ static int cache_map(struct dm_target *ti, struct bio *bio)
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r = policy_map(cache->policy, block, false, can_migrate, discarded_block,
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r = policy_map(cache->policy, block, false, can_migrate, discarded_block,
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bio, &lookup_result);
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bio, &lookup_result);
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if (r == -EWOULDBLOCK) {
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if (r == -EWOULDBLOCK) {
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cell_defer(cache, cell, true);
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cell_defer(cache, *cell, true);
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return DM_MAPIO_SUBMITTED;
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return DM_MAPIO_SUBMITTED;
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} else if (r) {
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} else if (r) {
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DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r);
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DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r);
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cell_defer(cache, *cell, false);
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bio_io_error(bio);
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bio_io_error(bio);
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return DM_MAPIO_SUBMITTED;
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return DM_MAPIO_SUBMITTED;
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}
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}
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@ -2476,52 +2500,44 @@ static int cache_map(struct dm_target *ti, struct bio *bio)
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* We need to invalidate this block, so
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* We need to invalidate this block, so
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* defer for the worker thread.
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* defer for the worker thread.
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*/
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*/
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cell_defer(cache, cell, true);
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cell_defer(cache, *cell, true);
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r = DM_MAPIO_SUBMITTED;
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r = DM_MAPIO_SUBMITTED;
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} else {
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} else {
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pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
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inc_miss_counter(cache, bio);
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inc_miss_counter(cache, bio);
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remap_to_origin_clear_discard(cache, bio, block);
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remap_to_origin_clear_discard(cache, bio, block);
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cell_defer(cache, cell, false);
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}
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}
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} else {
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} else {
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inc_hit_counter(cache, bio);
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inc_hit_counter(cache, bio);
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pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
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if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
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if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
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!is_dirty(cache, lookup_result.cblock))
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!is_dirty(cache, lookup_result.cblock))
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remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
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remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
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else
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else
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remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
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remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
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cell_defer(cache, cell, false);
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}
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}
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break;
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break;
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case POLICY_MISS:
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case POLICY_MISS:
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inc_miss_counter(cache, bio);
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inc_miss_counter(cache, bio);
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pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
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if (pb->req_nr != 0) {
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if (pb->req_nr != 0) {
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/*
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/*
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* This is a duplicate writethrough io that is no
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* This is a duplicate writethrough io that is no
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* longer needed because the block has been demoted.
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* longer needed because the block has been demoted.
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*/
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*/
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bio_endio(bio, 0);
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bio_endio(bio, 0);
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cell_defer(cache, cell, false);
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cell_defer(cache, *cell, false);
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return DM_MAPIO_SUBMITTED;
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r = DM_MAPIO_SUBMITTED;
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} else {
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} else
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remap_to_origin_clear_discard(cache, bio, block);
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remap_to_origin_clear_discard(cache, bio, block);
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cell_defer(cache, cell, false);
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}
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break;
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break;
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default:
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default:
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DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__,
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DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__,
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(unsigned) lookup_result.op);
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(unsigned) lookup_result.op);
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cell_defer(cache, *cell, false);
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bio_io_error(bio);
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bio_io_error(bio);
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r = DM_MAPIO_SUBMITTED;
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r = DM_MAPIO_SUBMITTED;
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}
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}
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@ -2529,6 +2545,21 @@ static int cache_map(struct dm_target *ti, struct bio *bio)
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return r;
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return r;
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}
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}
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static int cache_map(struct dm_target *ti, struct bio *bio)
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{
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int r;
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struct dm_bio_prison_cell *cell;
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struct cache *cache = ti->private;
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r = __cache_map(cache, bio, &cell);
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if (r == DM_MAPIO_REMAPPED) {
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inc_ds(cache, bio, cell);
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cell_defer(cache, cell, false);
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}
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return r;
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}
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static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
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static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
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{
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{
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struct cache *cache = ti->private;
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struct cache *cache = ti->private;
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@ -3072,7 +3103,7 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
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static struct target_type cache_target = {
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static struct target_type cache_target = {
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.name = "cache",
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.name = "cache",
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.version = {1, 4, 0},
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.version = {1, 5, 0},
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.module = THIS_MODULE,
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.module = THIS_MODULE,
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.ctr = cache_ctr,
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.ctr = cache_ctr,
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.dtr = cache_dtr,
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.dtr = cache_dtr,
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Загрузка…
Ссылка в новой задаче