From patchwork Wed Feb 16 04:45:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 12747949 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6CCEDC433F5 for ; Wed, 16 Feb 2022 04:46:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241616AbiBPEq4 (ORCPT ); Tue, 15 Feb 2022 23:46:56 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:47298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344418AbiBPEq4 (ORCPT ); Tue, 15 Feb 2022 23:46:56 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B39E0F463E for ; Tue, 15 Feb 2022 20:46:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644986803; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/Bmh36K5fD5JebZeJB6Qpy8FpXprH4pgDq1Xi51RGgk=; b=V61lkDTyRru3ZCaN23aAccht3yl+37g1E4TGkg+c+K928nskFsmunHcy7E7fktNZi15hcG vL0hsbS5b6zVEMzqgNEYig/byfG31yU+6rEBIBsrMur7yIaPHB0IaDY/LcfGAjva6dXZID EXyQesP1T91uU7vfZwX/ooUYpQzH3wU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-133-AXxD1GwBMrG-j-7FaoNl6g-1; Tue, 15 Feb 2022 23:46:40 -0500 X-MC-Unique: AXxD1GwBMrG-j-7FaoNl6g-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7372C809B7D; Wed, 16 Feb 2022 04:46:39 +0000 (UTC) Received: from localhost (ovpn-8-27.pek2.redhat.com [10.72.8.27]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1EA925ED29; Wed, 16 Feb 2022 04:46:37 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Ning Li , Tejun Heo , Chunguang Xu , Ming Lei Subject: [PATCH V4 6/8] block: throttle split bio in case of iops limit Date: Wed, 16 Feb 2022 12:45:12 +0800 Message-Id: <20220216044514.2903784-7-ming.lei@redhat.com> In-Reply-To: <20220216044514.2903784-1-ming.lei@redhat.com> References: <20220216044514.2903784-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Commit 111be8839817 ("block-throttle: avoid double charge") marks bio as BIO_THROTTLED unconditionally if __blk_throtl_bio() is called on this bio, then this bio won't be called into __blk_throtl_bio() any more. This way is to avoid double charge in case of bio splitting. It is reasonable for read/write throughput limit, but not reasonable for IOPS limit because block layer provides io accounting against split bio. Chunguang Xu has already observed this issue and fixed it in commit 4f1e9630afe6 ("blk-throtl: optimize IOPS throttle for large IO scenarios"). However, that patch only covers bio splitting in __blk_queue_split(), and we have other kind of bio splitting, such as bio_split() & submit_bio_noacct() and other ways. This patch tries to fix the issue in one generic way by always charging the bio for iops limit in blk_throtl_bio(). This way is reasonable: re-submission & fast-cloned bio is charged if it is submitted to same disk/queue, and BIO_THROTTLED will be cleared if bio->bi_bdev is changed. This new approach can get much more smooth/stable iops limit compared with commit 4f1e9630afe6 ("blk-throtl: optimize IOPS throttle for large IO scenarios") since that commit can't throttle current split bios actually. Also this way won't cause new double bio iops charge in blk_throtl_dispatch_work_fn() in which blk_throtl_bio() won't be called any more. Reported-by: Ning Li Acked-by: Tejun Heo Cc: Chunguang Xu Signed-off-by: Ming Lei --- block/blk-merge.c | 2 -- block/blk-throttle.c | 10 +++++++--- block/blk-throttle.h | 2 -- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 4de34a332c9f..f5255991b773 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -368,8 +368,6 @@ void __blk_queue_split(struct request_queue *q, struct bio **bio, trace_block_split(split, (*bio)->bi_iter.bi_sector); submit_bio_noacct(*bio); *bio = split; - - blk_throtl_charge_bio_split(*bio); } } diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 8770768f1000..c7aa26d52e84 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -807,7 +807,8 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; unsigned int bio_size = throtl_bio_data_size(bio); - if (bps_limit == U64_MAX) { + /* no need to throttle if this bio's bytes have been accounted */ + if (bps_limit == U64_MAX || bio_flagged(bio, BIO_THROTTLED)) { if (wait) *wait = 0; return true; @@ -919,9 +920,12 @@ static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio) unsigned int bio_size = throtl_bio_data_size(bio); /* Charge the bio to the group */ - tg->bytes_disp[rw] += bio_size; + if (!bio_flagged(bio, BIO_THROTTLED)) { + tg->bytes_disp[rw] += bio_size; + tg->last_bytes_disp[rw] += bio_size; + } + tg->io_disp[rw]++; - tg->last_bytes_disp[rw] += bio_size; tg->last_io_disp[rw]++; /* diff --git a/block/blk-throttle.h b/block/blk-throttle.h index 175f03abd9e4..cb43f4417d6e 100644 --- a/block/blk-throttle.h +++ b/block/blk-throttle.h @@ -170,8 +170,6 @@ static inline bool blk_throtl_bio(struct bio *bio) { struct throtl_grp *tg = blkg_to_tg(bio->bi_blkg); - if (bio_flagged(bio, BIO_THROTTLED)) - return false; if (!tg->has_rules[bio_data_dir(bio)]) return false;