[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>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9f7482d..05d79af 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;