From 924e600d417ead9ef67043988055ba236f114718 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Sat, 6 Mar 2010 02:32:33 +0000 Subject: [PATCH] dm: eliminate some holes data structures Eliminate a 4-byte hole in 'struct dm_io_memory' by moving 'offset' above the 'ptr' to which it applies (size reduced from 24 to 16 bytes). And by association, 1-4 byte hole is eliminated in 'struct dm_io_request' (size reduced from 56 to 48 bytes). Eliminate all 6 4-byte holes and 1 cache-line in 'struct dm_snapshot' (size reduced from 392 to 368 bytes). Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon --- drivers/md/dm-snap.c | 26 +++++++++++++------------- include/linux/dm-io.h | 4 ++-- 2 files changed, 15 insertions(+), 15 deletions(-) diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 0789c22..5485377 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -83,10 +83,10 @@ struct dm_snapshot { /* Whether or not owning mapped_device is suspended */ int suspended; - mempool_t *pending_pool; - atomic_t pending_exceptions_count; + mempool_t *pending_pool; + struct dm_exception_table pending; struct dm_exception_table complete; @@ -96,6 +96,11 @@ struct dm_snapshot { */ spinlock_t pe_lock; + /* Chunks with outstanding reads */ + spinlock_t tracked_chunk_lock; + mempool_t *tracked_chunk_pool; + struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE]; + /* The on disk metadata handler */ struct dm_exception_store *store; @@ -105,10 +110,12 @@ struct dm_snapshot { struct bio_list queued_bios; struct work_struct queued_bios_work; - /* Chunks with outstanding reads */ - mempool_t *tracked_chunk_pool; - spinlock_t tracked_chunk_lock; - struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE]; + /* Wait for events based on state_bits */ + unsigned long state_bits; + + /* Range of chunks currently being merged. */ + chunk_t first_merging_chunk; + int num_merging_chunks; /* * The merge operation failed if this flag is set. @@ -125,13 +132,6 @@ struct dm_snapshot { */ int merge_failed; - /* Wait for events based on state_bits */ - unsigned long state_bits; - - /* Range of chunks currently being merged. */ - chunk_t first_merging_chunk; - int num_merging_chunks; - /* * Incoming bios that overlap with chunks being merged must wait * for them to be committed. diff --git a/include/linux/dm-io.h b/include/linux/dm-io.h index b6bf17e..5c9186b 100644 --- a/include/linux/dm-io.h +++ b/include/linux/dm-io.h @@ -37,14 +37,14 @@ enum dm_io_mem_type { struct dm_io_memory { enum dm_io_mem_type type; + unsigned offset; + union { struct page_list *pl; struct bio_vec *bvec; void *vma; void *addr; } ptr; - - unsigned offset; }; struct dm_io_notify { -- 1.8.2.3