From: Junichi Nomura Date: Fri, 3 Oct 2014 11:55:26 +0000 (+0000) Subject: dm: use bioset_create_nobvec() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3d8aab2d2cca2dc878e396196d07889129440798;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git dm: use bioset_create_nobvec() 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 Signed-off-by: Mike Snitzer --- diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 0b9de07d585b..56a2c74c9a3f 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2895,7 +2895,7 @@ 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_create_nobvec(pool_size, front_pad); if (!pools->bs) goto out;