From: Junichi Nomura <j-nomura@xxxxxxxxxxxxx> Since DM core uses bio_clone_fast() for both bio-based and request-based DM devices there is no need for DM's bioset to have a bvec mempool. With this patch, on arch with 4KB page for example, memory usage will be reduced by 64KB for each bio-based DM device and 1MB for each request-based DM device. For example, when you create 10,000 bio-based DM devices and 1,000 request-based DM devices, memory usage of biovec under no load is: # grep biovec /proc/slabinfo biovec-256 418068 418068 4096 ... biovec-128 0 0 2048 ... biovec-64 0 0 1024 ... biovec-16 0 0 256 ... With this patch series applied, the usage becomes: # grep biovec /proc/slabinfo biovec-256 116 116 4096 ... biovec-128 0 0 2048 ... biovec-64 0 0 1024 ... biovec-16 0 0 256 ... So 4096 * (418068 - 116) = 1.6GB of memory is saved in this example. Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> --- drivers/md/dm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index aaeed99..f78ac7f 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -3021,7 +3021,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, u if (!pools->io_pool) goto out; - pools->bs = bioset_create(pool_size, front_pad); + pools->bs = bioset_nobvec_create(pool_size, front_pad); if (!pools->bs) goto out; -- 1.9.3 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
