From patchwork Fri Feb 20 23:27:15 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonthan Brassow X-Patchwork-Id: 8223 Received: from hormel.redhat.com (hormel1.redhat.com [209.132.177.33]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n1KNRJ5v030989 for ; Fri, 20 Feb 2009 23:27:20 GMT Received: from listman.util.phx.redhat.com (listman.util.phx.redhat.com [10.8.4.110]) by hormel.redhat.com (Postfix) with ESMTP id 9395D8E0498; Fri, 20 Feb 2009 18:27:19 -0500 (EST) Received: from int-mx2.corp.redhat.com (nat-pool.util.phx.redhat.com [10.8.5.200]) by listman.util.phx.redhat.com (8.13.1/8.13.1) with ESMTP id n1KNRHG9001266 for ; Fri, 20 Feb 2009 18:27:17 -0500 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n1KNRHKA014951 for ; Fri, 20 Feb 2009 18:27:17 -0500 Received: from [10.15.80.1] (hydrogen.msp.redhat.com [10.15.80.1]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n1KNRGTN028893 for ; Fri, 20 Feb 2009 18:27:16 -0500 From: Jonathan Brassow To: dm-devel@redhat.com Date: Fri, 20 Feb 2009 17:27:15 -0600 Message-Id: <1235172435.24593.42.camel@hydrogen.msp.redhat.com> Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 X-loop: dm-devel@redhat.com Subject: [dm-devel] [PATCH 12 of 17] dm-snap-remove-completed-exception-cache.patch X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.5 Precedence: junk Reply-To: device-mapper development List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com No need for snapshots to keep track of completed exceptions anymore, since the exception store implementations can do that (better) now. RFC-by: Jonathan Brassow --- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel Index: linux-2.6/drivers/md/dm-snap.c =================================================================== --- linux-2.6.orig/drivers/md/dm-snap.c +++ linux-2.6/drivers/md/dm-snap.c @@ -70,7 +70,6 @@ struct dm_snapshot { atomic_t pending_exceptions_count; struct dm_exception_table *pending; - struct dm_exception_table *complete; /* * pe_lock protects all pending_exception operations and access @@ -157,7 +156,6 @@ struct dm_snap_pending_exception { * Hash table mapping origin volumes to lists of snapshots and * a lock to protect it */ -static struct kmem_cache *exception_cache; static struct kmem_cache *pending_cache; struct dm_snap_tracked_chunk { @@ -337,22 +335,6 @@ static void unregister_snapshot(struct d up_write(&_origins_lock); } -static struct dm_exception *alloc_completed_exception(void *unused) -{ - struct dm_exception *e; - - e = kmem_cache_alloc(exception_cache, GFP_NOIO); - if (!e) - e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); - - return e; -} - -static void free_completed_exception(struct dm_exception *e, void *unused) -{ - kmem_cache_free(exception_cache, e); -} - static struct dm_exception *alloc_pending_exception(void *context) { struct dm_snapshot *s = context; @@ -379,29 +361,6 @@ static void free_pending_exception(struc } /* - * Callback used by the exception stores to load exceptions when - * initialising. - */ -static int dm_add_exception(void *context, chunk_t old, chunk_t new) -{ - struct dm_snapshot *s = context; - struct dm_exception *e; - - e = dm_alloc_exception(s->complete); - if (!e) - return -ENOMEM; - - e->old_chunk = old; - - /* Consecutive_count is implicitly initialised to zero */ - e->new_chunk = new; - - dm_insert_exception(s->complete, e); - - return 0; -} - -/* * Hard coded magic. */ static int calc_max_buckets(void) @@ -432,18 +391,6 @@ static int init_hash_tables(struct dm_sn hash_size = min(hash_size, max_buckets); hash_size = rounddown_pow_of_two(hash_size); - - s->complete = dm_exception_table_create(hash_size, - DM_CHUNK_CONSECUTIVE_BITS, - alloc_completed_exception, NULL, - free_completed_exception, NULL); - if (!s->complete) - return -ENOMEM; - - /* - * Allocate hash table for in-flight exceptions - * Make this smaller than the real hash table - */ hash_size >>= 3; if (hash_size < 64) hash_size = 64; @@ -451,10 +398,8 @@ static int init_hash_tables(struct dm_sn s->pending = dm_exception_table_create(hash_size, 0, alloc_pending_exception, s, free_pending_exception, NULL); - if (!s->pending) { - dm_exception_table_destroy(s->complete); + if (!s->pending) return -ENOMEM; - } return 0; } @@ -606,18 +551,6 @@ static int snapshot_ctr(struct dm_target INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]); spin_lock_init(&s->tracked_chunk_lock); - - /* Metadata must only be loaded into one table at once */ - r = s->store->type->read_metadata(s->store, dm_add_exception, - (void *)s); - if (r < 0) { - ti->error = "Failed to read snapshot metadata"; - goto bad_load_and_register; - } else if (r > 0) { - s->valid = 0; - DMWARN("Snapshot is marked invalid."); - } - bio_list_init(&s->queued_bios); INIT_WORK(&s->queued_bios_work, flush_queued_bios); @@ -645,7 +578,6 @@ bad_pending_pool: bad_kcopyd: dm_exception_table_destroy(s->pending); - dm_exception_table_destroy(s->complete); bad_hash_tables: dm_put_device(ti, s->origin); @@ -665,7 +597,6 @@ static void __free_exceptions(struct dm_ s->kcopyd_client = NULL; dm_exception_table_destroy(s->pending); - dm_exception_table_destroy(s->complete); } static void snapshot_dtr(struct dm_target *ti) @@ -804,7 +735,6 @@ static struct bio *put_pending_exception static void pending_complete(struct dm_snap_pending_exception *pe, int success) { - struct dm_exception *e; struct dm_snapshot *s = pe->snap; struct bio *origin_bios = NULL; struct bio *snapshot_bios = NULL; @@ -818,18 +748,8 @@ static void pending_complete(struct dm_s goto out; } - e = dm_alloc_exception(s->complete); - if (!e) { - down_write(&s->lock); - __invalidate_snapshot(s, -ENOMEM); - error = 1; - goto out; - } - *e = pe->e; - down_write(&s->lock); if (!s->valid) { - dm_free_exception(s->complete, e); error = 1; goto out; } @@ -841,12 +761,6 @@ static void pending_complete(struct dm_s while (__chunk_is_tracked(s, pe->e.old_chunk)) msleep(1); - /* - * Add a proper exception, and remove the - * in-flight exception from the list. - */ - dm_insert_exception(s->complete, e); - out: dm_remove_exception(&pe->e); snapshot_bios = bio_list_get(&pe->snapshot_bios); @@ -1408,25 +1322,18 @@ static int __init dm_snapshot_init(void) goto bad2; } - exception_cache = KMEM_CACHE(dm_exception, 0); - if (!exception_cache) { - DMERR("Couldn't create exception cache."); - r = -ENOMEM; - goto bad3; - } - pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); if (!pending_cache) { DMERR("Couldn't create pending cache."); r = -ENOMEM; - goto bad4; + goto bad3; } tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0); if (!tracked_chunk_cache) { DMERR("Couldn't create cache to track chunks in use."); r = -ENOMEM; - goto bad5; + goto bad4; } ksnapd = create_singlethread_workqueue("ksnapd"); @@ -1440,10 +1347,8 @@ static int __init dm_snapshot_init(void) bad_pending_pool: kmem_cache_destroy(tracked_chunk_cache); -bad5: - kmem_cache_destroy(pending_cache); bad4: - kmem_cache_destroy(exception_cache); + kmem_cache_destroy(pending_cache); bad3: exit_origin_hash(); bad2: @@ -1464,7 +1369,6 @@ static void __exit dm_snapshot_exit(void exit_origin_hash(); kmem_cache_destroy(pending_cache); - kmem_cache_destroy(exception_cache); kmem_cache_destroy(tracked_chunk_cache); dm_exception_store_exit();