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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD9EEC433F5 for ; Tue, 12 Oct 2021 15:14:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2EA260C4A for ; Tue, 12 Oct 2021 15:14:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235317AbhJLPQM (ORCPT ); Tue, 12 Oct 2021 11:16:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:32194 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229633AbhJLPQL (ORCPT ); Tue, 12 Oct 2021 11:16:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634051649; 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=2xvN2vLxgg7nr/3sm0rZxnDgmYjVBd3T2S4YxkSk3YY=; b=UH8xot7bRgz3vSt+nKIup9VGpl81ONdftqc2hb96QR9f1+YhSzBzOT8M9tOnJf5RLAnxfC TZkE9evLAkdKFYESP1eK0X9mMvExydslrX5tBYsgoHhHCIc3PGnosRCGIt+Yt5AoMV68hC V0KsHXJmug6X56D0Sp1DxaGYnwypTiM= 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-470-i9Dvu8TpNbmzFE8yTvmj4A-1; Tue, 12 Oct 2021 11:14:08 -0400 X-MC-Unique: i9Dvu8TpNbmzFE8yTvmj4A-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9719B112A0A0; Tue, 12 Oct 2021 15:14:06 +0000 (UTC) Received: from T590 (ovpn-8-34.pek2.redhat.com [10.72.8.34]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5AC0F196FA; Tue, 12 Oct 2021 15:14:01 +0000 (UTC) Date: Tue, 12 Oct 2021 23:13:56 +0800 From: Ming Lei To: Christoph Hellwig Cc: Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Chaitanya Kulkarni , Sagi Grimberg , Keith Busch , Bart Van Assche Subject: Re: [PATCH V3 6/6] blk-mq: support concurrent queue quiesce/unquiesce Message-ID: References: <20211009034713.1489183-1-ming.lei@redhat.com> <20211009034713.1489183-7-ming.lei@redhat.com> <20211012103010.GA29640@lst.de> <20211012150827.GB20571@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211012150827.GB20571@lst.de> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Oct 12, 2021 at 05:08:27PM +0200, Christoph Hellwig wrote: > On Tue, Oct 12, 2021 at 11:06:51PM +0800, Ming Lei wrote: > > > We can get rid of the QUEUE_FLAG_QUIESCED flag now and just look > > > at ->quiesce_depth directly. > > > > I'd rather not to do that given we need to check QUEUE_FLAG_QUIESCED in fast > > path. > > Checking an integer vs checking a bit is easier actually faster or at > least the same speed depending on the architecture / micro architecture. ->queue_flag is always hot, but quiesce_depth can't be and shouldn't be since it is used very less. -- Ming