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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 5B892C433DF for ; Fri, 7 Aug 2020 13:49:58 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 2C6AC221E2 for ; Fri, 7 Aug 2020 13:49:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="tBIeY67b"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hTE8TKGf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C6AC221E2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=i44otb6WRVreQHKCdzuRhN4hW/Gl6zg49r0oH0dHdu0=; b=tBIeY67bIpa+2UIzkkrcQoha+ snWhTNht8gcQIWhx4FYuCFwIg9bhag0t5fXJ5nqLnKocrD4GXkV45t8jmhOy3+Um91lkUPwgk48/t dDAPi7LNPG1rCxKwZy2D3Zb2CGHLwuGFOObZnzyeLVAi5iuHRkPFenBSVxEpGcGNp0jZZyTF5vSYA VOEJliMx0IXkMDI66ehCFeMPaslnNIvDJuzGK+EmLri3TDmev/k/XhWM+Qdqix1dVp3bcHvqIvCe2 iclTEUzNipOwQC5OLDsS+2vpQ3numXQVmN/ytVtO7fTIsyqoYj24V44+xPvzFRyG79JEsnyESRf33 MG+rLpiqw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k42kp-00045f-O7; Fri, 07 Aug 2020 13:49:51 +0000 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120] helo=us-smtp-1.mimecast.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k42km-00045H-Rb for linux-nvme@lists.infradead.org; Fri, 07 Aug 2020 13:49:49 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596808188; 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=AxKhj+gkO/EgGki1oR3mHYFMo4D2Y/mcsgmgyosbzNM=; b=hTE8TKGfJ3cCjl7RH3X0ZiWAzGpsrlq42kPTRMBy88REisEvvSpI6NO4hGsR6Z48cT4G+d N7UprgvYPHe2xp7LFJ7nBs80yC1dzXhTKy8KnUM81iMNiolppdb1ZJM61Z5J88MPCs7AWN 4N6grEIR8m68Xd3wRfAXN45Sj9oN0/0= 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-138-uNIENScWM26AP91v3UsCoQ-1; Fri, 07 Aug 2020 09:49:46 -0400 X-MC-Unique: uNIENScWM26AP91v3UsCoQ-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 8301379EEC; Fri, 7 Aug 2020 13:49:44 +0000 (UTC) Received: from T590 (ovpn-12-80.pek2.redhat.com [10.72.12.80]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 707876FEDC; Fri, 7 Aug 2020 13:49:37 +0000 (UTC) Date: Fri, 7 Aug 2020 21:49:32 +0800 From: Ming Lei To: Chao Leng Subject: Re: [PATCH v2 0/3] reduce quiesce time for lots of name spaces Message-ID: <20200807134932.GA2122627@T590> References: <20200807090559.29582-1-lengchao@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200807090559.29582-1-lengchao@huawei.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200807_094948_983158_0E0A13DE X-CRM114-Status: GOOD ( 11.64 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: axboe@fb.com, sagi@grimberg.me, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, kbusch@kernel.org, hch@lst.de Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Aug 07, 2020 at 05:05:59PM +0800, Chao Leng wrote: > nvme_stop_queues quiesce queues for all name spaces, now quiesce one by > one, if there is lots of name spaces, sync wait long time(more than 10s). > Multipath can not fail over to retry quickly, cause io pause long time. > This is not expected. > To reduce quiesce time, we introduce async mechanism for sync SRCUs > and quiesce queue. > Frankly speaking, I prefer to replace SRCU with percpu_refcount: - percpu_refcount has much less memory footprint than SRCU, so we can simply move percpu_refcount into request_queue, instead of adding more bytes into each hctx by this patch - percpu_ref_get()/percpu_ref_put() isn't slower than srcu_read_lock()/srcu_read_unlock(). - with percpu_refcount, we can remove 'srcu_idx' from hctx_lock/hctx_unlock() Thanks, Ming _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme