From patchwork Wed Sep 30 09:46:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: cenjiahui X-Patchwork-Id: 272388 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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 E750CC4727E for ; Wed, 30 Sep 2020 09:52:28 +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 637B62075F for ; Wed, 30 Sep 2020 09:52:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 637B62075F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:32882 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kNYmh-0004e9-K4 for qemu-devel@archiver.kernel.org; Wed, 30 Sep 2020 05:52:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37564) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kNYhS-00073N-5I for qemu-devel@nongnu.org; Wed, 30 Sep 2020 05:47:02 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:5156 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kNYhM-0003oG-Sn for qemu-devel@nongnu.org; Wed, 30 Sep 2020 05:47:01 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 36DBC4306B37C9C4DB62; Wed, 30 Sep 2020 17:46:53 +0800 (CST) Received: from localhost (10.174.186.107) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.487.0; Wed, 30 Sep 2020 17:46:43 +0800 From: Jiahui Cen To: Subject: [RFC PATCH v2 4/8] block-backend: add I/O rehandle pause/unpause Date: Wed, 30 Sep 2020 17:46:02 +0800 Message-ID: <20200930094606.5323-5-cenjiahui@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200930094606.5323-1-cenjiahui@huawei.com> References: <20200930094606.5323-1-cenjiahui@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.186.107] X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.190; envelope-from=cenjiahui@huawei.com; helo=huawei.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/30 05:46:53 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: kwolf@redhat.com, fangying1@huawei.com, cenjiahui@huawei.com, zhang.zhanghailiang@huawei.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Sometimes there is no need to rehandle AIOs although I/O hang is enabled. For example, when deleting a block backend, we have to wait AIO completed by calling blk_drain(), but not care about the results. So a pause interface of I/O hang is helpful to bypass the rehandle mechanism. Signed-off-by: Jiahui Cen Signed-off-by: Ying Fang --- block/block-backend.c | 60 +++++++++++++++++++++++++++++++--- include/sysemu/block-backend.h | 2 ++ 2 files changed, 58 insertions(+), 4 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 90fcc678b5..c16d95a2c9 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -37,6 +37,9 @@ static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb); /* block backend rehandle timer interval 5s */ #define BLOCK_BACKEND_REHANDLE_TIMER_INTERVAL 5000 +#define BLOCK_BACKEND_REHANDLE_NORMAL 1 +#define BLOCK_BACKEND_REHANDLE_DRAIN_REQUESTED 2 +#define BLOCK_BACKEND_REHANDLE_DRAINED 3 enum BlockIOHangStatus { BLOCK_IO_HANG_STATUS_NORMAL = 0, @@ -50,6 +53,8 @@ typedef struct BlockBackendRehandleInfo { unsigned int in_flight; QTAILQ_HEAD(, BlkAioEmAIOCB) re_aios; + + int status; } BlockBackendRehandleInfo; typedef struct BlockBackendAioNotifier { @@ -2461,6 +2466,51 @@ static void blk_rehandle_remove_aiocb(BlockBackend *blk, BlkAioEmAIOCB *acb) qatomic_dec(&blk->reinfo.in_flight); } +static void blk_rehandle_drain(BlockBackend *blk) +{ + if (blk_bs(blk)) { + bdrv_drained_begin(blk_bs(blk)); + BDRV_POLL_WHILE(blk_bs(blk), qatomic_read(&blk->reinfo.in_flight) > 0); + bdrv_drained_end(blk_bs(blk)); + } +} + +static bool blk_rehandle_is_paused(BlockBackend *blk) +{ + return blk->reinfo.status == BLOCK_BACKEND_REHANDLE_DRAIN_REQUESTED || + blk->reinfo.status == BLOCK_BACKEND_REHANDLE_DRAINED; +} + +void blk_rehandle_pause(BlockBackend *blk) +{ + BlockBackendRehandleInfo *reinfo = &blk->reinfo; + + aio_context_acquire(blk_get_aio_context(blk)); + if (!reinfo->enable || reinfo->status == BLOCK_BACKEND_REHANDLE_DRAINED) { + aio_context_release(blk_get_aio_context(blk)); + return; + } + + reinfo->status = BLOCK_BACKEND_REHANDLE_DRAIN_REQUESTED; + blk_rehandle_drain(blk); + reinfo->status = BLOCK_BACKEND_REHANDLE_DRAINED; + aio_context_release(blk_get_aio_context(blk)); +} + +void blk_rehandle_unpause(BlockBackend *blk) +{ + BlockBackendRehandleInfo *reinfo = &blk->reinfo; + + aio_context_acquire(blk_get_aio_context(blk)); + if (!reinfo->enable || reinfo->status == BLOCK_BACKEND_REHANDLE_NORMAL) { + aio_context_release(blk_get_aio_context(blk)); + return; + } + + reinfo->status = BLOCK_BACKEND_REHANDLE_NORMAL; + aio_context_release(blk_get_aio_context(blk)); +} + static void blk_rehandle_timer_cb(void *opaque) { BlockBackend *blk = opaque; @@ -2560,10 +2610,12 @@ static void blk_rehandle_aio_complete(BlkAioEmAIOCB *acb) if (acb->has_returned) { blk_dec_in_flight(acb->rwco.blk); - need_rehandle = blk_rehandle_aio(acb, &has_timeout); - if (need_rehandle) { - blk_rehandle_insert_aiocb(acb->rwco.blk, acb); - return; + if (!blk_rehandle_is_paused(acb->rwco.blk)) { + need_rehandle = blk_rehandle_aio(acb, &has_timeout); + if (need_rehandle) { + blk_rehandle_insert_aiocb(acb->rwco.blk, acb); + return; + } } acb->common.cb(acb->common.opaque, acb->rwco.ret); diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index bfebe3a960..391a047444 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -268,6 +268,8 @@ const BdrvChild *blk_root(BlockBackend *blk); int blk_make_empty(BlockBackend *blk, Error **errp); +void blk_rehandle_pause(BlockBackend *blk); +void blk_rehandle_unpause(BlockBackend *blk); void blk_iohang_init(BlockBackend *blk, int64_t iohang_timeout); #endif