diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-04-02 19:55:24 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-04-02 19:55:24 +0100 |
| commit | 95f8fac8dc6139fedfb87746e0c8fda9b803cb46 (patch) | |
| tree | 36c980967ee188865d0a58be2e1281b5bf77cbae /drivers/md | |
| parent | a920f6b3accc77d9dddbc98a7426be23ee479625 (diff) | |
dm raid1: switch read_record from kmalloc to slab to save memory
With my previous patch to save bi_io_vec, the size of dm_raid1_read_record
is significantly increased (the vector list takes 3072 bytes on 32-bit machines
and 4096 bytes on 64-bit machines).
The structure dm_raid1_read_record used to be allocated with kmalloc,
but kmalloc aligns the size on the next power-of-two so an object
slightly greater than 4096 will allocate 8192 bytes of memory and half of
that memory will be wasted.
This patch turns kmalloc into a slab cache which doesn't have this
padding so it will reduce the memory consumed.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-raid1.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index 4d6bc101962..62d594889ac 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -145,6 +145,8 @@ struct dm_raid1_read_record { struct dm_bio_details details; }; +static struct kmem_cache *_dm_raid1_read_record_cache; + /* * Every mirror should look like this one. */ @@ -764,9 +766,9 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors, atomic_set(&ms->suspend, 0); atomic_set(&ms->default_mirror, DEFAULT_MIRROR); - len = sizeof(struct dm_raid1_read_record); - ms->read_record_pool = mempool_create_kmalloc_pool(MIN_READ_RECORDS, - len); + ms->read_record_pool = mempool_create_slab_pool(MIN_READ_RECORDS, + _dm_raid1_read_record_cache); + if (!ms->read_record_pool) { ti->error = "Error creating mirror read_record_pool"; kfree(ms); @@ -1279,16 +1281,31 @@ static int __init dm_mirror_init(void) { int r; + _dm_raid1_read_record_cache = KMEM_CACHE(dm_raid1_read_record, 0); + if (!_dm_raid1_read_record_cache) { + DMERR("Can't allocate dm_raid1_read_record cache"); + r = -ENOMEM; + goto bad_cache; + } + r = dm_register_target(&mirror_target); - if (r < 0) + if (r < 0) { DMERR("Failed to register mirror target"); + goto bad_target; + } + + return 0; +bad_target: + kmem_cache_destroy(_dm_raid1_read_record_cache); +bad_cache: return r; } static void __exit dm_mirror_exit(void) { dm_unregister_target(&mirror_target); + kmem_cache_destroy(_dm_raid1_read_record_cache); } /* Module hooks */ |