Commit 11dfce50 authored Oct 03, 2014 by Junichi Nomura Committed by Jens Axboe Oct 03, 2014

block: use bio_clone_fast() in blk_rq_prep_clone()



Request cloning clones bios in the request to track the completion
of each bio.
For that purpose, we can use bio_clone_fast() instead of bio_clone()
to avoid unnecessary allocation and copy of bvecs.

This patch reduces memory footprint of request-based device-mapper
(about 1-4KB for each request) and is a preparation for further
reduction of memory usage by removing unused bvec mempool.

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

parent 4a0efdc9

block/blk-core.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2926,7 +2926,7 @@ int blk_rq_prep_clone(struct request rq, struct request rq_src,
		blk_rq_init(NULL, rq);

		__rq_for_each_bio(bio_src, rq_src) {
		bio = bio_clone_bioset(bio_src, gfp_mask, bs);
		bio = bio_clone_fast(bio_src, gfp_mask, bs);
		if (!bio)
		goto free_and_out;

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