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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 4520AC432C0 for ; Wed, 20 Nov 2019 23:26:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C43D20885 for ; Wed, 20 Nov 2019 23:26:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="lKkjgQ2T" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726335AbfKTX0y (ORCPT ); Wed, 20 Nov 2019 18:26:54 -0500 Received: from mail.skyhub.de ([5.9.137.197]:55652 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725820AbfKTX0y (ORCPT ); Wed, 20 Nov 2019 18:26:54 -0500 Received: from zn.tnic (p200300EC2F0D8C0040FB9E04CC44F6A0.dip0.t-ipconnect.de [IPv6:2003:ec:2f0d:8c00:40fb:9e04:cc44:f6a0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 31F9D1EC0A02; Thu, 21 Nov 2019 00:26:53 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1574292413; 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:in-reply-to:in-reply-to: references:references; bh=/XYqnRGAq6RG2RaGU9yxebpQvpxNBGiW9TEKW3oyXbM=; b=lKkjgQ2T4h40tR3ptv2+Ho1zJ71DoGz1OC7Y7iondHIz8kvLm6kBedwzbTyR4uSvpRbh40 7CJGlyL06XPdxbchffvVnrrfvKU3JttbS2AeXxJUIt///Hbbq7bUNOY9eRowN8q6ZmMUiz PNA1yyyVk24Zt8TwOx/e0dS1er5Azto= Date: Thu, 21 Nov 2019 00:26:45 +0100 From: Borislav Petkov To: "Luck, Tony" Cc: Dave Jiang , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, vkoul@kernel.org, dan.j.williams@intel.com, jing.lin@intel.com, ashok.raj@intel.com, sanjay.k.kumar@intel.com, megha.dey@intel.com, jacob.jun.pan@intel.com, yi.l.liu@intel.com, axboe@kernel.dk, akpm@linux-foundation.org, tglx@linutronix.de, mingo@redhat.com, fenghua.yu@intel.com, hpa@zytor.com Subject: Re: [PATCH RFC 01/14] x86/asm: add iosubmit_cmds512() based on movdir64b CPU instruction Message-ID: <20191120232645.GO2634@zn.tnic> References: <157428480574.36836.14057238306923901253.stgit@djiang5-desk3.ch.intel.com> <157428502934.36836.8119026517510193201.stgit@djiang5-desk3.ch.intel.com> <20191120215338.GN2634@zn.tnic> <20191120231923.GA32680@agluck-desk2.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191120231923.GA32680@agluck-desk2.amr.corp.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On Wed, Nov 20, 2019 at 03:19:23PM -0800, Luck, Tony wrote: > That's the underlying functionality of the MOVDIR64B instruction. A > posted write so no way to know if it succeeded. So how do you know whether any of the writes went through? > When using dedicated queues the caller must keep count of how many > operations are in flight and not send more than the depth of the > queue. This way? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette