aboutsummaryrefslogtreecommitdiff
path: root/drivers/md/dm-io.c
diff options
context:
space:
mode:
authorMikulas Patocka <mpatocka@redhat.com>2011-05-29 13:03:09 +0100
committerAlasdair G Kergon <agk@redhat.com>2011-05-29 13:03:09 +0100
commitbda8efec5c706a672e0714d341a342e811f0262a (patch)
tree7daf7b505723f5ed2767353dc3fe53b939c46d87 /drivers/md/dm-io.c
parentd04714580f12379fcf7a0f799e86c92b96dd4e1f (diff)
downloadlinux-bda8efec5c706a672e0714d341a342e811f0262a.tar.gz
dm io: use fixed initial mempool size
Replace the arbitrary calculation of an initial io struct mempool size with a constant. The code calculated the number of reserved structures based on the request size and used a "magic" multiplication constant of 4. This patch changes it to reserve a fixed number - itself still chosen quite arbitrarily. Further testing might show if there is a better number to choose. Note that if there is no memory pressure, we can still allocate an arbitrary number of "struct io" structures. One structure is enough to process the whole request. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-io.c')
-rw-r--r--drivers/md/dm-io.c27
1 files changed, 5 insertions, 22 deletions
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 76a5af00a26..2067288f61f 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -19,6 +19,8 @@
#define DM_MSG_PREFIX "io"
#define DM_IO_MAX_REGIONS BITS_PER_LONG
+#define MIN_IOS 16
+#define MIN_BIOS 16
struct dm_io_client {
mempool_t *pool;
@@ -41,33 +43,21 @@ struct io {
static struct kmem_cache *_dm_io_cache;
/*
- * io contexts are only dynamically allocated for asynchronous
- * io. Since async io is likely to be the majority of io we'll
- * have the same number of io contexts as bios! (FIXME: must reduce this).
- */
-
-static unsigned int pages_to_ios(unsigned int pages)
-{
- return 4 * pages; /* too many ? */
-}
-
-/*
* Create a client with mempool and bioset.
*/
-struct dm_io_client *dm_io_client_create(unsigned num_pages)
+struct dm_io_client *dm_io_client_create(void)
{
- unsigned ios = pages_to_ios(num_pages);
struct dm_io_client *client;
client = kmalloc(sizeof(*client), GFP_KERNEL);
if (!client)
return ERR_PTR(-ENOMEM);
- client->pool = mempool_create_slab_pool(ios, _dm_io_cache);
+ client->pool = mempool_create_slab_pool(MIN_IOS, _dm_io_cache);
if (!client->pool)
goto bad;
- client->bios = bioset_create(16, 0);
+ client->bios = bioset_create(MIN_BIOS, 0);
if (!client->bios)
goto bad;
@@ -81,13 +71,6 @@ struct dm_io_client *dm_io_client_create(unsigned num_pages)
}
EXPORT_SYMBOL(dm_io_client_create);
-int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client)
-{
- return mempool_resize(client->pool, pages_to_ios(num_pages),
- GFP_KERNEL);
-}
-EXPORT_SYMBOL(dm_io_client_resize);
-
void dm_io_client_destroy(struct dm_io_client *client)
{
mempool_destroy(client->pool);