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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 E6166C433C1 for ; Fri, 19 Mar 2021 17:39:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBEA661925 for ; Fri, 19 Mar 2021 17:39:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230024AbhCSRil (ORCPT ); Fri, 19 Mar 2021 13:38:41 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:45550 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230047AbhCSRi0 (ORCPT ); Fri, 19 Mar 2021 13:38:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616175505; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=m+8xF8gYUrkReXcd+pmBcxm2zbrVki0YD9Q60+pRbu8=; b=NitXZgv83ex/2jIwYBZZ3scMhqV9DKdwh6KqI3xT77xtPVIep1MOwT7JAwTFcQGb/LTacn R0MVecsPZ4WChZ9T6aiHVbJkhtfb9/CZ/FCvhkL0SRQH+U60eGazibSbH3Bbt6QhlEhMHA eGJDucHX70IM22gAI2omIk91B615tIk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-384-8nmvxrDfOAGyjMUTlNQHbw-1; Fri, 19 Mar 2021 13:38:22 -0400 X-MC-Unique: 8nmvxrDfOAGyjMUTlNQHbw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DA4A28018A1; Fri, 19 Mar 2021 17:38:20 +0000 (UTC) Received: from localhost (unknown [10.18.25.174]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 69B5060613; Fri, 19 Mar 2021 17:38:14 +0000 (UTC) Date: Fri, 19 Mar 2021 13:38:13 -0400 From: Mike Snitzer To: Ming Lei Cc: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig , Jeffle Xu , dm-devel@redhat.com Subject: Re: [RFC PATCH V2 05/13] block: add req flag of REQ_TAG Message-ID: <20210319173813.GC9938@redhat.com> References: <20210318164827.1481133-1-ming.lei@redhat.com> <20210318164827.1481133-6-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210318164827.1481133-6-ming.lei@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Mar 18 2021 at 12:48pm -0400, Ming Lei wrote: > Add one req flag REQ_TAG which will be used in the following patch for > supporting bio based IO polling. "REQ_TAG" is so generic yet is used in such a specific way (to mark an FS bio as having polling context) I don't have a great suggestion for a better name, just seems "REQ_TAG" is lacking... (especially given the potential for confusion due to blk-mq's notion of "tag"). REQ_FS? REQ_FS_CTX? REQ_POLL? REQ_POLL_CTX? REQ_NAMING_IS_HARD :) Maybe others have better ideas? Mike > Exactly this flag can help us to do: > > 1) request flag is cloned in bio_fast_clone(), so if we mark one FS bio > as REQ_TAG, all bios cloned from this FS bio will be marked as REQ_TAG. > > 2)create per-task io polling context if the bio based queue supports polling > and the submitted bio is HIPRI. This per-task io polling context will be > created during submit_bio() before marking this HIPRI bio as REQ_TAG. Then > we can avoid to create such io polling context if one cloned bio with REQ_TAG > is submitted from another kernel context. > > 3) for supporting bio based io polling, we need to poll IOs from all > underlying queues of bio device/driver, this way help us to recognize which > IOs need to polled in bio based style, which will be implemented in next > patch. > > Signed-off-by: Ming Lei > --- > block/blk-core.c | 29 +++++++++++++++++++++++++++-- > include/linux/blk_types.h | 4 ++++ > 2 files changed, 31 insertions(+), 2 deletions(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index 0b00c21cbefb..efc7a61a84b4 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -840,11 +840,30 @@ static inline bool blk_queue_support_bio_poll(struct request_queue *q) > static inline void blk_bio_poll_preprocess(struct request_queue *q, > struct bio *bio) > { > + bool mq; > + > if (!(bio->bi_opf & REQ_HIPRI)) > return; > > - if (!blk_queue_poll(q) || (!queue_is_mq(q) && !blk_get_bio_poll_ctx())) > + /* > + * Can't support bio based IO poll without per-task poll queue > + * > + * Now we have created per-task io poll context, and mark this > + * bio as REQ_TAG, so: 1) if any cloned bio from this bio is > + * submitted from another kernel context, we won't create bio > + * poll context for it, so that bio will be completed by IRQ; > + * 2) If such bio is submitted from current context, we will > + * complete it via blk_poll(); 3) If driver knows that one > + * underlying bio allocated from driver is for FS bio, meantime > + * it is submitted in current context, driver can mark such bio > + * as REQ_TAG manually, so the bio can be completed via blk_poll > + * too. > + */ > + mq = queue_is_mq(q); > + if (!blk_queue_poll(q) || (!mq && !blk_get_bio_poll_ctx())) > bio->bi_opf &= ~REQ_HIPRI; > + else if (!mq) > + bio->bi_opf |= REQ_TAG; > } > > static noinline_for_stack bool submit_bio_checks(struct bio *bio) > @@ -893,9 +912,15 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio) > > /* > * Created per-task io poll queue if we supports bio polling > - * and it is one HIPRI bio. > + * and it is one HIPRI bio, and this HIPRI bio has to be from > + * FS. If REQ_TAG isn't set for HIPRI bio, we think it originated > + * from FS. > + * > + * Driver may allocated bio by itself and REQ_TAG is set, but they > + * won't be marked as HIPRI. > */ > blk_create_io_context(q, blk_queue_support_bio_poll(q) && > + !(bio->bi_opf & REQ_TAG) && > (bio->bi_opf & REQ_HIPRI)); > > blk_bio_poll_preprocess(q, bio); > diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h > index db026b6ec15a..a1bcade4bcc3 100644 > --- a/include/linux/blk_types.h > +++ b/include/linux/blk_types.h > @@ -394,6 +394,9 @@ enum req_flag_bits { > > __REQ_HIPRI, > > + /* for marking IOs originated from same FS bio in same context */ > + __REQ_TAG, > + > /* for driver use */ > __REQ_DRV, > __REQ_SWAP, /* swapping request. */ > @@ -418,6 +421,7 @@ enum req_flag_bits { > > #define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP) > #define REQ_HIPRI (1ULL << __REQ_HIPRI) > +#define REQ_TAG (1ULL << __REQ_TAG) > > #define REQ_DRV (1ULL << __REQ_DRV) > #define REQ_SWAP (1ULL << __REQ_SWAP) > -- > 2.29.2 > 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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 3B641C433DB for ; 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Fri, 19 Mar 2021 17:38:22 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 12JHcK5j018539 for ; Fri, 19 Mar 2021 13:38:20 -0400 Received: by smtp.corp.redhat.com (Postfix) id D735B60C16; Fri, 19 Mar 2021 17:38:20 +0000 (UTC) Received: from localhost (unknown [10.18.25.174]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 69B5060613; Fri, 19 Mar 2021 17:38:14 +0000 (UTC) Date: Fri, 19 Mar 2021 13:38:13 -0400 From: Mike Snitzer To: Ming Lei Message-ID: <20210319173813.GC9938@redhat.com> References: <20210318164827.1481133-1-ming.lei@redhat.com> <20210318164827.1481133-6-ming.lei@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210318164827.1481133-6-ming.lei@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-loop: dm-devel@redhat.com Cc: Jens Axboe , linux-block@vger.kernel.org, dm-devel@redhat.com, Jeffle Xu , Christoph Hellwig Subject: Re: [dm-devel] [RFC PATCH V2 05/13] block: add req flag of REQ_TAG X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Thu, Mar 18 2021 at 12:48pm -0400, Ming Lei wrote: > Add one req flag REQ_TAG which will be used in the following patch for > supporting bio based IO polling. "REQ_TAG" is so generic yet is used in such a specific way (to mark an FS bio as having polling context) I don't have a great suggestion for a better name, just seems "REQ_TAG" is lacking... (especially given the potential for confusion due to blk-mq's notion of "tag"). REQ_FS? REQ_FS_CTX? REQ_POLL? REQ_POLL_CTX? REQ_NAMING_IS_HARD :) Maybe others have better ideas? Mike > Exactly this flag can help us to do: > > 1) request flag is cloned in bio_fast_clone(), so if we mark one FS bio > as REQ_TAG, all bios cloned from this FS bio will be marked as REQ_TAG. > > 2)create per-task io polling context if the bio based queue supports polling > and the submitted bio is HIPRI. This per-task io polling context will be > created during submit_bio() before marking this HIPRI bio as REQ_TAG. Then > we can avoid to create such io polling context if one cloned bio with REQ_TAG > is submitted from another kernel context. > > 3) for supporting bio based io polling, we need to poll IOs from all > underlying queues of bio device/driver, this way help us to recognize which > IOs need to polled in bio based style, which will be implemented in next > patch. > > Signed-off-by: Ming Lei > --- > block/blk-core.c | 29 +++++++++++++++++++++++++++-- > include/linux/blk_types.h | 4 ++++ > 2 files changed, 31 insertions(+), 2 deletions(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index 0b00c21cbefb..efc7a61a84b4 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -840,11 +840,30 @@ static inline bool blk_queue_support_bio_poll(struct request_queue *q) > static inline void blk_bio_poll_preprocess(struct request_queue *q, > struct bio *bio) > { > + bool mq; > + > if (!(bio->bi_opf & REQ_HIPRI)) > return; > > - if (!blk_queue_poll(q) || (!queue_is_mq(q) && !blk_get_bio_poll_ctx())) > + /* > + * Can't support bio based IO poll without per-task poll queue > + * > + * Now we have created per-task io poll context, and mark this > + * bio as REQ_TAG, so: 1) if any cloned bio from this bio is > + * submitted from another kernel context, we won't create bio > + * poll context for it, so that bio will be completed by IRQ; > + * 2) If such bio is submitted from current context, we will > + * complete it via blk_poll(); 3) If driver knows that one > + * underlying bio allocated from driver is for FS bio, meantime > + * it is submitted in current context, driver can mark such bio > + * as REQ_TAG manually, so the bio can be completed via blk_poll > + * too. > + */ > + mq = queue_is_mq(q); > + if (!blk_queue_poll(q) || (!mq && !blk_get_bio_poll_ctx())) > bio->bi_opf &= ~REQ_HIPRI; > + else if (!mq) > + bio->bi_opf |= REQ_TAG; > } > > static noinline_for_stack bool submit_bio_checks(struct bio *bio) > @@ -893,9 +912,15 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio) > > /* > * Created per-task io poll queue if we supports bio polling > - * and it is one HIPRI bio. > + * and it is one HIPRI bio, and this HIPRI bio has to be from > + * FS. If REQ_TAG isn't set for HIPRI bio, we think it originated > + * from FS. > + * > + * Driver may allocated bio by itself and REQ_TAG is set, but they > + * won't be marked as HIPRI. > */ > blk_create_io_context(q, blk_queue_support_bio_poll(q) && > + !(bio->bi_opf & REQ_TAG) && > (bio->bi_opf & REQ_HIPRI)); > > blk_bio_poll_preprocess(q, bio); > diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h > index db026b6ec15a..a1bcade4bcc3 100644 > --- a/include/linux/blk_types.h > +++ b/include/linux/blk_types.h > @@ -394,6 +394,9 @@ enum req_flag_bits { > > __REQ_HIPRI, > > + /* for marking IOs originated from same FS bio in same context */ > + __REQ_TAG, > + > /* for driver use */ > __REQ_DRV, > __REQ_SWAP, /* swapping request. */ > @@ -418,6 +421,7 @@ enum req_flag_bits { > > #define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP) > #define REQ_HIPRI (1ULL << __REQ_HIPRI) > +#define REQ_TAG (1ULL << __REQ_TAG) > > #define REQ_DRV (1ULL << __REQ_DRV) > #define REQ_SWAP (1ULL << __REQ_SWAP) > -- > 2.29.2 > -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel