diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2014-01-13 19:13:05 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2014-01-14 23:23:03 -0500 |
| commit | 55b082e614e219fb5199a6f93e648ed35d3c96d5 (patch) | |
| tree | a2707e62bdd914e9651e78cde6cb55a5f0b88d7f /drivers/md/dm-bufio.c | |
| parent | 55494bf2947dccdf2d98b62374fea7365dfead84 (diff) | |
dm snapshot: use dm-bufio prefetch
This patch modifies dm-snapshot so that it prefetches the buffers when
loading the exceptions.
The number of buffers read ahead is specified in the DM_PREFETCH_CHUNKS
macro. The current value for DM_PREFETCH_CHUNKS (12) was found to
provide the best performance on a single 15k SCSI spindle. In the
future we may modify this default or make it configurable.
Also, introduce the function dm_bufio_set_minimum_buffers to setup
bufio's number of internal buffers before freeing happens. dm-bufio may
hold more buffers if enough memory is available. There is no guarantee
that the specified number of buffers will be available - if you need a
guarantee, use the argument reserved_buffers for
dm_bufio_client_create.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-bufio.c')
| -rw-r--r-- | drivers/md/dm-bufio.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index d86593721915..9ed42125514b 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -104,6 +104,8 @@ struct dm_bufio_client { struct list_head reserved_buffers; unsigned need_reserved_buffers; + unsigned minimum_buffers; + struct hlist_head *cache_hash; wait_queue_head_t free_buffer_wait; @@ -861,8 +863,8 @@ static void __get_memory_limit(struct dm_bufio_client *c, buffers = dm_bufio_cache_size_per_client >> (c->sectors_per_block_bits + SECTOR_SHIFT); - if (buffers < DM_BUFIO_MIN_BUFFERS) - buffers = DM_BUFIO_MIN_BUFFERS; + if (buffers < c->minimum_buffers) + buffers = c->minimum_buffers; *limit_buffers = buffers; *threshold_buffers = buffers * DM_BUFIO_WRITEBACK_PERCENT / 100; @@ -1372,6 +1374,12 @@ void dm_bufio_forget(struct dm_bufio_client *c, sector_t block) } EXPORT_SYMBOL(dm_bufio_forget); +void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned n) +{ + c->minimum_buffers = n; +} +EXPORT_SYMBOL(dm_bufio_set_minimum_buffers); + unsigned dm_bufio_get_block_size(struct dm_bufio_client *c) { return c->block_size; @@ -1568,6 +1576,8 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign INIT_LIST_HEAD(&c->reserved_buffers); c->need_reserved_buffers = reserved_buffers; + c->minimum_buffers = DM_BUFIO_MIN_BUFFERS; + init_waitqueue_head(&c->free_buffer_wait); c->async_write_error = 0; |