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 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 6B740C43381 for ; Wed, 27 Feb 2019 12:40:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 359A92133D for ; Wed, 27 Feb 2019 12:40:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730044AbfB0Mkd (ORCPT ); Wed, 27 Feb 2019 07:40:33 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57632 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726419AbfB0Mkd (ORCPT ); Wed, 27 Feb 2019 07:40:33 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9C16EFA8C0; Wed, 27 Feb 2019 12:40:33 +0000 (UTC) Received: from localhost (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9952919C71; Wed, 27 Feb 2019 12:40:29 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Ming Lei Subject: [PATCH 1/4] block: introduce bvec_nth_page() Date: Wed, 27 Feb 2019 20:40:10 +0800 Message-Id: <20190227124013.4828-2-ming.lei@redhat.com> In-Reply-To: <20190227124013.4828-1-ming.lei@redhat.com> References: <20190227124013.4828-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 27 Feb 2019 12:40:33 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Single-page bvec can often be seen in small BS workloads, so introduce bvec_nth_page() for avoiding to call nth_page() unnecessarily, which looks not cheap. Signed-off-by: Ming Lei --- block/blk-merge.c | 2 +- include/linux/bvec.h | 11 ++++++++--- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 066b66430523..c7e8a8273460 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -483,7 +483,7 @@ static unsigned blk_bvec_map_sg(struct request_queue *q, offset = (total + bvec->bv_offset) % PAGE_SIZE; idx = (total + bvec->bv_offset) / PAGE_SIZE; - pg = nth_page(bvec->bv_page, idx); + pg = bvec_nth_page(bvec->bv_page, idx); sg_set_page(*sg, pg, seg_size, offset); diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 30a57b68d017..4376f683c08a 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -51,6 +51,11 @@ struct bvec_iter_all { unsigned done; }; +static inline struct page *bvec_nth_page(struct page *page, int idx) +{ + return idx == 0 ? page : nth_page(page, idx); +} + /* * various member access, note that bio_data should of course not be used * on highmem page vectors @@ -87,8 +92,8 @@ struct bvec_iter_all { PAGE_SIZE - bvec_iter_offset((bvec), (iter))) #define bvec_iter_page(bvec, iter) \ - nth_page(mp_bvec_iter_page((bvec), (iter)), \ - mp_bvec_iter_page_idx((bvec), (iter))) + bvec_nth_page(mp_bvec_iter_page((bvec), (iter)), \ + mp_bvec_iter_page_idx((bvec), (iter))) #define bvec_iter_bvec(bvec, iter) \ ((struct bio_vec) { \ @@ -171,7 +176,7 @@ static inline void mp_bvec_last_segment(const struct bio_vec *bvec, unsigned total = bvec->bv_offset + bvec->bv_len; unsigned last_page = (total - 1) / PAGE_SIZE; - seg->bv_page = nth_page(bvec->bv_page, last_page); + seg->bv_page = bvec_nth_page(bvec->bv_page, last_page); /* the whole segment is inside the last page */ if (bvec->bv_offset >= last_page * PAGE_SIZE) { -- 2.9.5