From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8AB61C43381 for ; Fri, 29 Mar 2019 07:09:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 648B02183F for ; Fri, 29 Mar 2019 07:09:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728715AbfC2HJO (ORCPT ); Fri, 29 Mar 2019 03:09:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32982 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728651AbfC2HJN (ORCPT ); Fri, 29 Mar 2019 03:09:13 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2E3FA83F51; Fri, 29 Mar 2019 07:09:13 +0000 (UTC) Received: from localhost (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id 16FD9179F8; Fri, 29 Mar 2019 07:09:07 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Ming Lei , Omar Sandoval , Christoph Hellwig Subject: [PATCH V3 10/10] block: don't check if adjacent bvecs in one bio can be mergeable Date: Fri, 29 Mar 2019 15:08:03 +0800 Message-Id: <20190329070803.10958-11-ming.lei@redhat.com> In-Reply-To: <20190329070803.10958-1-ming.lei@redhat.com> References: <20190329070803.10958-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 29 Mar 2019 07:09:13 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Now both passthrough and FS IO have supported multi-page bvec, and bvec merging has been handled actually when adding page to bio, then adjacent bvecs won't be mergeable any more if they belong to same bio. So only try to merge bvecs if they are from different bios. Cc: Omar Sandoval Cc: Christoph Hellwig Signed-off-by: Ming Lei --- block/blk-merge.c | 69 +++++++++++++++++++++++++++++++++---------------------- 1 file changed, 42 insertions(+), 27 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 3e934ee9a907..8f96d683b577 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -354,11 +354,11 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, struct bio *bio) { struct bio_vec bv, bvprv = { NULL }; - int prev = 0; unsigned int seg_size, nr_phys_segs; unsigned front_seg_size; struct bio *fbio, *bbio; struct bvec_iter iter; + bool new_bio = false; if (!bio) return 0; @@ -379,7 +379,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, nr_phys_segs = 0; for_each_bio(bio) { bio_for_each_bvec(bv, bio, iter) { - if (prev) { + if (new_bio) { if (seg_size + bv.bv_len > queue_max_segment_size(q)) goto new_segment; @@ -387,7 +387,6 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, goto new_segment; seg_size += bv.bv_len; - bvprv = bv; if (nr_phys_segs == 1 && seg_size > front_seg_size) @@ -396,12 +395,13 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, continue; } new_segment: - bvprv = bv; - prev = 1; bvec_split_segs(q, &bv, &nr_phys_segs, &seg_size, &front_seg_size, NULL, UINT_MAX); + new_bio = false; } bbio = bio; + bvprv = bv; + new_bio = true; } fbio->bi_seg_front_size = front_seg_size; @@ -501,29 +501,26 @@ static inline int __blk_bvec_map_sg(struct bio_vec bv, return 1; } -static inline void -__blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, - struct scatterlist *sglist, struct bio_vec *bvprv, - struct scatterlist **sg, int *nsegs) +/* only try to merge bvecs into one sg if they are from two bios */ +static inline bool +__blk_segment_map_sg_merge(struct request_queue *q, struct bio_vec *bvec, + struct bio_vec *bvprv, struct scatterlist **sg) { int nbytes = bvec->bv_len; - if (*sg) { - if ((*sg)->length + nbytes > queue_max_segment_size(q)) - goto new_segment; - if (!biovec_phys_mergeable(q, bvprv, bvec)) - goto new_segment; + if (!*sg) + return false; - (*sg)->length += nbytes; - } else { -new_segment: - if (bvec->bv_offset + bvec->bv_len <= PAGE_SIZE) { - (*nsegs) += __blk_bvec_map_sg(*bvec, sglist, sg); - } else - (*nsegs) += blk_bvec_map_sg(q, bvec, sglist, sg); - } - *bvprv = *bvec; + if ((*sg)->length + nbytes > queue_max_segment_size(q)) + return false; + + if (!biovec_phys_mergeable(q, bvprv, bvec)) + return false; + + (*sg)->length += nbytes; + + return true; } static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, @@ -533,11 +530,29 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, struct bio_vec bvec, bvprv = { NULL }; struct bvec_iter iter; int nsegs = 0; + bool new_bio = false; - for_each_bio(bio) - bio_for_each_bvec(bvec, bio, iter) - __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, - &nsegs); + for_each_bio(bio) { + bio_for_each_bvec(bvec, bio, iter) { + /* + * Only try to merge bvecs from two bios given we + * have done bio internal merge when adding pages + * to bio + */ + if (new_bio && + __blk_segment_map_sg_merge(q, &bvec, &bvprv, sg)) + goto next_bvec; + + if (bvec.bv_offset + bvec.bv_len <= PAGE_SIZE) + nsegs += __blk_bvec_map_sg(bvec, sglist, sg); + else + nsegs += blk_bvec_map_sg(q, &bvec, sglist, sg); + next_bvec: + new_bio = false; + } + bvprv = bvec; + new_bio = true; + } return nsegs; } -- 2.9.5