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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 500DDC46470 for ; Mon, 13 May 2019 15:10:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 21797208C3 for ; Mon, 13 May 2019 15:10:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557760222; bh=dIt/4Y8eQ1NLKeViEN/VABRn8TZR/smeBqN1WTYGPJc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=VBp6ptNNo71Ib4yfQza45YWUQULZrNbRAQUCoG7hBtvhBhP1iZabvUKAiR74m6oxj XQJ+DFoJTS0Rg5iqxC+StP7S77nEvztqGgSyiHy0St0yW/Z5LwEFhz/u2vMBrgICXM hZFbVFpqjlH+TYO/C6BY5OEXuo2nQhvpt/LLq7xs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730937AbfEMPKV (ORCPT ); Mon, 13 May 2019 11:10:21 -0400 Received: from mga01.intel.com ([192.55.52.88]:60387 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727339AbfEMPKV (ORCPT ); Mon, 13 May 2019 11:10:21 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 May 2019 08:10:20 -0700 X-ExtLoop1: 1 Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by fmsmga008.fm.intel.com with ESMTP; 13 May 2019 08:10:20 -0700 Date: Mon, 13 May 2019 09:04:58 -0600 From: Keith Busch To: Mario.Limonciello@dell.com Cc: hch@lst.de, keith.busch@intel.com, sagi@grimberg.me, linux-nvme@lists.infradead.org, rafael@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, kai.heng.feng@canonical.com Subject: Re: [PATCH] nvme/pci: Use host managed power state for suspend Message-ID: <20190513150458.GA15437@localhost.localdomain> References: <20190510212937.11661-1-keith.busch@intel.com> <0080aaff18e5445dabca509d4113eca8@AUSX13MPC105.AMER.DELL.COM> <955722d8fc16425dbba0698c4806f8fd@AUSX13MPC105.AMER.DELL.COM> <20190513143741.GA25500@lst.de> <20190513145522.GA15421@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 13, 2019 at 03:05:42PM +0000, Mario.Limonciello@dell.com wrote: > This system power state - suspend to idle is going to freeze threads. > But we're talking a multi threaded kernel. Can't there be a timing problem going > on then too? With a disk flush being active in one task and the other task trying > to put the disk into the deepest power state. If you don't freeze the queues how > can you guarantee that didn't happen? But if an active data flush task is running, then we're not idle and shouldn't go to low power.