[BLOCK] Don't pin lots of memory in mempools

Currently we scale the mempool sizes depending on memory installed
in the machine, except for the bio pool itself which sits at a fixed
256 entry pre-allocation.

There's really no point in "optimizing" this OOM path, we just need
enough preallocated to make progress. A single unit is enough, lets
scale it down to 2 just to be on the safe side.

This patch saves ~150kb of pinned kernel memory on a 32-bit box.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

4 files changed, 4 insertions, 4 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 4c2471ee054a..d8121234c347 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -867,7 +867,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                 goto bad4;
         }
 
-        cc->bs = bioset_create(MIN_IOS, MIN_IOS, 4);
+        cc->bs = bioset_create(MIN_IOS, MIN_IOS);
         if (!cc->bs) {
                 ti->error = "Cannot allocate crypt bioset";
                 goto bad_bs;
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 4eb73d395213..8bdc8a87b249 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -60,7 +60,7 @@ static int resize_pool(unsigned int new_ios)
                 if (!_io_pool)
                         return -ENOMEM;
 
-                _bios = bioset_create(16, 16, 4);
+                _bios = bioset_create(16, 16);
                 if (!_bios) {
                         mempool_destroy(_io_pool);
                         _io_pool = NULL;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3668b170ea68..11a98df298ec 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1012,7 +1012,7 @@ static struct mapped_device *alloc_dev(int minor)
         if (!md->tio_pool)
                 goto bad3;
 
-        md->bs = bioset_create(16, 16, 4);
+        md->bs = bioset_create(16, 16);
         if (!md->bs)
                 goto bad_no_bioset;
 
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9f7482d0b594..05d79af5ab90 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -31,7 +31,7 @@
 
 
 #define SG_MEMPOOL_NR           ARRAY_SIZE(scsi_sg_pools)
-#define SG_MEMPOOL_SIZE         32
+#define SG_MEMPOOL_SIZE         2
 
 struct scsi_host_sg_pool {
         size_t          size;