From patchwork Tue May 19 17:11:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 282348 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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MIME_BASE64_TEXT,SIGNED_OFF_BY,SPF_HELO_NONE,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 79B80C433DF for ; Tue, 19 May 2020 17:13:06 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3B26220709 for ; Tue, 19 May 2020 17:13:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RyegRFRk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B26220709 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43132 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jb5nd-0004JI-BG for qemu-devel@archiver.kernel.org; Tue, 19 May 2020 13:13:05 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34106) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jb5mS-0002mE-2m for qemu-devel@nongnu.org; Tue, 19 May 2020 13:11:52 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:24942 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jb5mR-0002Sr-59 for qemu-devel@nongnu.org; Tue, 19 May 2020 13:11:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589908309; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QqQP2gEWiHT1RhvkO6A6rp0yPTnbuodhCHyBJ6H7YKQ=; b=RyegRFRkOHxneAmOZH2kxbbC7ggeAjhGG2GL9QaBuDCrJspE4aEsu/5YLHCp4aZARNDWRD EWWlJfbVcIfEdNEuRteqOkbiK3t6Hk0/kz+OfsuCCYBSOaT7mRg4GbTvOOLhYKSGb8mJVS fOq531XMB9jw/maLXykyVfqZrnjZB34= 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-2-6ArE6UUoOj-WBPTaYoCVug-1; Tue, 19 May 2020 13:11:47 -0400 X-MC-Unique: 6ArE6UUoOj-WBPTaYoCVug-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 08D7A57093; Tue, 19 May 2020 17:11:46 +0000 (UTC) Received: from localhost (ovpn-114-215.ams2.redhat.com [10.36.114.215]) by smtp.corp.redhat.com (Postfix) with ESMTP id 94E3A50F54; Tue, 19 May 2020 17:11:45 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 1/7] block/nvme: poll queues without q->lock Date: Tue, 19 May 2020 18:11:32 +0100 Message-Id: <20200519171138.201667-2-stefanha@redhat.com> In-Reply-To: <20200519171138.201667-1-stefanha@redhat.com> References: <20200519171138.201667-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/18 23:56:10 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Max Reitz , Stefan Hajnoczi , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" A lot of CPU time is spent simply locking/unlocking q->lock during polling. Check for completion outside the lock to make q->lock disappear from the profile. Signed-off-by: Stefan Hajnoczi --- block/nvme.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/block/nvme.c b/block/nvme.c index eb2f54dd9d..7eb4512666 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -512,6 +512,18 @@ static bool nvme_poll_queues(BDRVNVMeState *s) for (i = 0; i < s->nr_queues; i++) { NVMeQueuePair *q = s->queues[i]; + const size_t cqe_offset = q->cq.head * NVME_CQ_ENTRY_BYTES; + NvmeCqe *cqe = (NvmeCqe *)&q->cq.queue[cqe_offset]; + + /* + * q->lock isn't needed for checking completion because + * nvme_process_completion() only runs in the event loop thread and + * cannot race with itself. + */ + if ((le16_to_cpu(cqe->status) & 0x1) == q->cq_phase) { + continue; + } + qemu_mutex_lock(&q->lock); while (nvme_process_completion(s, q)) { /* Keep polling */ From patchwork Tue May 19 17:11:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 282346 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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MIME_BASE64_TEXT,SIGNED_OFF_BY,SPF_HELO_NONE,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 CDE5FC433DF for ; Tue, 19 May 2020 17:14:29 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 960B420709 for ; Tue, 19 May 2020 17:14:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="M0wx699M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 960B420709 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:50354 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jb5oy-0007GK-Rm for qemu-devel@archiver.kernel.org; Tue, 19 May 2020 13:14:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34280) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jb5ma-0002yq-Mo for qemu-devel@nongnu.org; Tue, 19 May 2020 13:12:00 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:38920 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jb5mW-0002Vn-Vw for qemu-devel@nongnu.org; Tue, 19 May 2020 13:12:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589908315; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sp0y+Zg3ajzpKsP0+NwKrmoN1WDadhwx00K7pgQg8F8=; b=M0wx699MizNFBq1HYFNdWxBNgv7Et0AgRhbCXFtbP9qqFcZ8K73Ml6hUem+kpYaEx14Vct dOs0sIIFjgEQUoKl16ON4tLqVZKibedaAZaBUAwhp5tiPtVO9pnjVtZSpqaCFHsUO7U/Np QPwWzqjyAxf0JiGMVrDIkqX05plmyZU= 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-433-qvQAiZXwNVOduU4I477xxA-1; Tue, 19 May 2020 13:11:53 -0400 X-MC-Unique: qvQAiZXwNVOduU4I477xxA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C3A601005510; Tue, 19 May 2020 17:11:52 +0000 (UTC) Received: from localhost (ovpn-114-215.ams2.redhat.com [10.36.114.215]) by smtp.corp.redhat.com (Postfix) with ESMTP id 58E3550F54; Tue, 19 May 2020 17:11:52 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 3/7] block/nvme: don't access CQE after moving cq.head Date: Tue, 19 May 2020 18:11:34 +0100 Message-Id: <20200519171138.201667-4-stefanha@redhat.com> In-Reply-To: <20200519171138.201667-1-stefanha@redhat.com> References: <20200519171138.201667-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/19 09:19:26 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Max Reitz , Stefan Hajnoczi , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Do not access a CQE after incrementing q->cq.head and releasing q->lock. It is unlikely that this causes problems in practice but it's a latent bug. The reason why it should be safe at the moment is that completion processing is not re-entrant and the CQ doorbell isn't written until the end of nvme_process_completion(). Make this change now because QEMU expects completion processing to be re-entrant and later patches will do that. Signed-off-by: Stefan Hajnoczi --- block/nvme.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/block/nvme.c b/block/nvme.c index 5286227074..6bf58bc6aa 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -321,11 +321,14 @@ static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q) q->busy = true; assert(q->inflight >= 0); while (q->inflight) { + int ret; int16_t cid; + c = (NvmeCqe *)&q->cq.queue[q->cq.head * NVME_CQ_ENTRY_BYTES]; if ((le16_to_cpu(c->status) & 0x1) == q->cq_phase) { break; } + ret = nvme_translate_error(c); q->cq.head = (q->cq.head + 1) % NVME_QUEUE_SIZE; if (!q->cq.head) { q->cq_phase = !q->cq_phase; @@ -344,7 +347,7 @@ static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q) preq->busy = false; preq->cb = preq->opaque = NULL; qemu_mutex_unlock(&q->lock); - req.cb(req.opaque, nvme_translate_error(c)); + req.cb(req.opaque, ret); qemu_mutex_lock(&q->lock); q->inflight--; progress = true; From patchwork Tue May 19 17:11:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 282345 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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MIME_BASE64_TEXT,SIGNED_OFF_BY,SPF_HELO_NONE,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 3CF2DC433E0 for ; Tue, 19 May 2020 17:15:46 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 08B5320578 for ; Tue, 19 May 2020 17:15:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZgEOj6hK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 08B5320578 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:54726 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jb5qD-0000ga-99 for qemu-devel@archiver.kernel.org; Tue, 19 May 2020 13:15:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34304) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jb5mc-00034K-RA for qemu-devel@nongnu.org; Tue, 19 May 2020 13:12:02 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:46398 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jb5mb-0002Zw-1v for qemu-devel@nongnu.org; Tue, 19 May 2020 13:12:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589908320; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gK+3NhfsKlN8RgvfVxbtX56OFKu6ouTjsvZ5gcQ+1uA=; b=ZgEOj6hKwVADEuLTGdFcs8G7NbkgbkwLXr1OhagImape192yTnviagJ7IFdjZZlLWUdhN8 ymeAQ7jhTnGf/ThpJLPOU6Wrx0om2oHi8gVgFsLmLk08stYTJCBnwsGSfPsPicAbVKLaWm G2ppidhyPa/2O3VCQz3Qpa8E58a0uKM= 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-13-4pVnU1JIP6mM4idJJZc23Q-1; Tue, 19 May 2020 13:11:58 -0400 X-MC-Unique: 4pVnU1JIP6mM4idJJZc23Q-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 7E9FD464; Tue, 19 May 2020 17:11:57 +0000 (UTC) Received: from localhost (ovpn-114-215.ams2.redhat.com [10.36.114.215]) by smtp.corp.redhat.com (Postfix) with ESMTP id 329485D9C5; Tue, 19 May 2020 17:11:54 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 4/7] block/nvme: switch to a NVMeRequest freelist Date: Tue, 19 May 2020 18:11:35 +0100 Message-Id: <20200519171138.201667-5-stefanha@redhat.com> In-Reply-To: <20200519171138.201667-1-stefanha@redhat.com> References: <20200519171138.201667-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.81; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/19 00:34:39 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Max Reitz , Stefan Hajnoczi , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" There are three issues with the current NVMeRequest->busy field: 1. The busy field is accidentally accessed outside q->lock when request submission fails. 2. Waiters on free_req_queue are not woken when a request is returned early due to submission failure. 2. Finding a free request involves scanning all requests. This makes request submission O(n^2). Switch to an O(1) freelist that is always accessed under the lock. Also differentiate between NVME_QUEUE_SIZE, the actual SQ/CQ size, and NVME_NUM_REQS, the number of usable requests. This makes the code simpler than using NVME_QUEUE_SIZE everywhere and having to keep in mind that one slot is reserved. Signed-off-by: Stefan Hajnoczi --- block/nvme.c | 81 ++++++++++++++++++++++++++++++++++------------------ 1 file changed, 54 insertions(+), 27 deletions(-) diff --git a/block/nvme.c b/block/nvme.c index 6bf58bc6aa..3ad4f27e1c 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -33,6 +33,12 @@ #define NVME_QUEUE_SIZE 128 #define NVME_BAR_SIZE 8192 +/* + * We have to leave one slot empty as that is the full queue case where + * head == tail + 1. + */ +#define NVME_NUM_REQS (NVME_QUEUE_SIZE - 1) + typedef struct { int32_t head, tail; uint8_t *queue; @@ -47,7 +53,7 @@ typedef struct { int cid; void *prp_list_page; uint64_t prp_list_iova; - bool busy; + int free_req_next; /* q->reqs[] index of next free req */ } NVMeRequest; typedef struct { @@ -61,7 +67,8 @@ typedef struct { /* Fields protected by @lock */ NVMeQueue sq, cq; int cq_phase; - NVMeRequest reqs[NVME_QUEUE_SIZE]; + int free_req_head; + NVMeRequest reqs[NVME_NUM_REQS]; bool busy; int need_kick; int inflight; @@ -200,19 +207,23 @@ static NVMeQueuePair *nvme_create_queue_pair(BlockDriverState *bs, qemu_mutex_init(&q->lock); q->index = idx; qemu_co_queue_init(&q->free_req_queue); - q->prp_list_pages = qemu_blockalign0(bs, s->page_size * NVME_QUEUE_SIZE); + q->prp_list_pages = qemu_blockalign0(bs, s->page_size * NVME_NUM_REQS); r = qemu_vfio_dma_map(s->vfio, q->prp_list_pages, - s->page_size * NVME_QUEUE_SIZE, + s->page_size * NVME_NUM_REQS, false, &prp_list_iova); if (r) { goto fail; } - for (i = 0; i < NVME_QUEUE_SIZE; i++) { + q->free_req_head = -1; + for (i = 0; i < NVME_NUM_REQS; i++) { NVMeRequest *req = &q->reqs[i]; req->cid = i + 1; + req->free_req_next = q->free_req_head; + q->free_req_head = i; req->prp_list_page = q->prp_list_pages + i * s->page_size; req->prp_list_iova = prp_list_iova + i * s->page_size; } + nvme_init_queue(bs, &q->sq, size, NVME_SQ_ENTRY_BYTES, &local_err); if (local_err) { error_propagate(errp, local_err); @@ -254,13 +265,11 @@ static void nvme_kick(BDRVNVMeState *s, NVMeQueuePair *q) */ static NVMeRequest *nvme_get_free_req(NVMeQueuePair *q) { - int i; - NVMeRequest *req = NULL; + NVMeRequest *req; qemu_mutex_lock(&q->lock); - while (q->inflight + q->need_kick > NVME_QUEUE_SIZE - 2) { - /* We have to leave one slot empty as that is the full queue case (head - * == tail + 1). */ + + while (q->free_req_head == -1) { if (qemu_in_coroutine()) { trace_nvme_free_req_queue_wait(q); qemu_co_queue_wait(&q->free_req_queue, &q->lock); @@ -269,20 +278,41 @@ static NVMeRequest *nvme_get_free_req(NVMeQueuePair *q) return NULL; } } - for (i = 0; i < NVME_QUEUE_SIZE; i++) { - if (!q->reqs[i].busy) { - q->reqs[i].busy = true; - req = &q->reqs[i]; - break; - } - } - /* We have checked inflight and need_kick while holding q->lock, so one - * free req must be available. */ - assert(req); + + req = &q->reqs[q->free_req_head]; + q->free_req_head = req->free_req_next; + req->free_req_next = -1; + qemu_mutex_unlock(&q->lock); return req; } +/* With q->lock */ +static void nvme_put_free_req_locked(NVMeQueuePair *q, NVMeRequest *req) +{ + req->free_req_next = q->free_req_head; + q->free_req_head = req - q->reqs; +} + +/* With q->lock */ +static void nvme_wake_free_req_locked(BDRVNVMeState *s, NVMeQueuePair *q) +{ + if (!qemu_co_queue_empty(&q->free_req_queue)) { + replay_bh_schedule_oneshot_event(s->aio_context, + nvme_free_req_queue_cb, q); + } +} + +/* Insert a request in the freelist and wake waiters */ +static void nvme_put_free_req_and_wake(BDRVNVMeState *s, NVMeQueuePair *q, + NVMeRequest *req) +{ + qemu_mutex_lock(&q->lock); + nvme_put_free_req_locked(q, req); + nvme_wake_free_req_locked(s, q); + qemu_mutex_unlock(&q->lock); +} + static inline int nvme_translate_error(const NvmeCqe *c) { uint16_t status = (le16_to_cpu(c->status) >> 1) & 0xFF; @@ -344,7 +374,7 @@ static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q) req = *preq; assert(req.cid == cid); assert(req.cb); - preq->busy = false; + nvme_put_free_req_locked(q, preq); preq->cb = preq->opaque = NULL; qemu_mutex_unlock(&q->lock); req.cb(req.opaque, ret); @@ -356,10 +386,7 @@ static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q) /* Notify the device so it can post more completions. */ smp_mb_release(); *q->cq.doorbell = cpu_to_le32(q->cq.head); - if (!qemu_co_queue_empty(&q->free_req_queue)) { - replay_bh_schedule_oneshot_event(s->aio_context, - nvme_free_req_queue_cb, q); - } + nvme_wake_free_req_locked(s, q); } q->busy = false; return progress; @@ -1001,7 +1028,7 @@ static coroutine_fn int nvme_co_prw_aligned(BlockDriverState *bs, r = nvme_cmd_map_qiov(bs, &cmd, req, qiov); qemu_co_mutex_unlock(&s->dma_map_lock); if (r) { - req->busy = false; + nvme_put_free_req_and_wake(s, ioq, req); return r; } nvme_submit_command(s, ioq, req, &cmd, nvme_rw_cb, &data); @@ -1218,7 +1245,7 @@ static int coroutine_fn nvme_co_pdiscard(BlockDriverState *bs, qemu_co_mutex_unlock(&s->dma_map_lock); if (ret) { - req->busy = false; + nvme_put_free_req_and_wake(s, ioq, req); goto out; } From patchwork Tue May 19 17:11:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 282347 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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MIME_BASE64_TEXT,SIGNED_OFF_BY,SPF_HELO_NONE,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 F3376C433E0 for ; Tue, 19 May 2020 17:13:42 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AE42620709 for ; Tue, 19 May 2020 17:13:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FLzcrY5Q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AE42620709 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46468 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jb5oD-0005hU-Tj for qemu-devel@archiver.kernel.org; Tue, 19 May 2020 13:13:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34316) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jb5me-00038L-99 for qemu-devel@nongnu.org; Tue, 19 May 2020 13:12:04 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:59305 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jb5md-0002bO-8o for qemu-devel@nongnu.org; Tue, 19 May 2020 13:12:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589908322; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=B1PloHl0i3aFCkds3d4WJY2dkXuAFWinlvjBOBk+wNM=; b=FLzcrY5QwelJsMB1pximflBfzijMleAr6Q7T5/XvGcgYRL4kRfbj+JXbuJ47UjqfcYCRNu 8iYUdHxlD/1bJkhgz3rTQ1rZPP1dEs5Sawyg7vp4LLCRgu078ernDWeSh2lwPJinXm7Wqv fTV6giqxStbie6mCT9Jc4uqHG6RrGIM= 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-252-qSOmlgPBNoub0-F7z0-JIg-1; Tue, 19 May 2020 13:12:00 -0400 X-MC-Unique: qSOmlgPBNoub0-F7z0-JIg-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 869F8464; Tue, 19 May 2020 17:11:59 +0000 (UTC) Received: from localhost (ovpn-114-215.ams2.redhat.com [10.36.114.215]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1E2A35D9C5; Tue, 19 May 2020 17:11:58 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 5/7] block/nvme: clarify that free_req_queue is protected by q->lock Date: Tue, 19 May 2020 18:11:36 +0100 Message-Id: <20200519171138.201667-6-stefanha@redhat.com> In-Reply-To: <20200519171138.201667-1-stefanha@redhat.com> References: <20200519171138.201667-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/18 23:56:10 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Max Reitz , Stefan Hajnoczi , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Existing users access free_req_queue under q->lock. Document this. Signed-off-by: Stefan Hajnoczi --- block/nvme.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/nvme.c b/block/nvme.c index 3ad4f27e1c..e32bff26ff 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -57,7 +57,6 @@ typedef struct { } NVMeRequest; typedef struct { - CoQueue free_req_queue; QemuMutex lock; /* Fields protected by BQL */ @@ -65,6 +64,7 @@ typedef struct { uint8_t *prp_list_pages; /* Fields protected by @lock */ + CoQueue free_req_queue; NVMeQueue sq, cq; int cq_phase; int free_req_head;