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=-1.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 679B7C43612 for ; Thu, 10 Jan 2019 23:47:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 368A72173B for ; Thu, 10 Jan 2019 23:47:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="SeF3SstE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730458AbfAJXrd (ORCPT ); Thu, 10 Jan 2019 18:47:33 -0500 Received: from mail-pg1-f193.google.com ([209.85.215.193]:40874 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730453AbfAJXrd (ORCPT ); Thu, 10 Jan 2019 18:47:33 -0500 Received: by mail-pg1-f193.google.com with SMTP id z10so5493626pgp.7 for ; Thu, 10 Jan 2019 15:47:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=orQTzzFZhstfOxWiPDU+V7t1O1pECdJw/+2s72IMmcc=; b=SeF3SstEcUZfYBuNQph+H/vpm0nE3gQjOSgxzfOtPxzP9J5er9sYzR4IzVrfSVEx6z N3QG+KB36CdlXbXrB1qHX6Lwpk+nYVOpQxGTwsn3gm7l+HCSeit9WQJ9SFnk3XK/KmB8 9hCBHmR9S1RR3Q+dsGd4BJs0tDhNx2+REAMzLRXtYT21+BhNYYD/TbZQzgEfI8EuUwJL IrzIzH5uzXBlxkenG3QcBbmEmQC9SDhvyF9t8WgClIBWpD8OAOGfxpRWk6qFDAr0ISMO ke26UR0YIC704qyK96xPOmirDKCK0Um8x2KzNGY09CoiwVL0gLZ9uvslF4B7xE/59fRe qrSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=orQTzzFZhstfOxWiPDU+V7t1O1pECdJw/+2s72IMmcc=; b=H5VaCIJwv62koVQI4KG+qD/LVrngUC9qsRBoC3jiISzye4hEmK1iU+2xV4yIgSVf/0 OVxxASxvE037G0Z0a7emM03fCEb/fSWEPqowpOhVo4mJg3NtXBpHFB+qN7Lz0/2dc3w2 mvWETJVDiY/YPTzqQOWaBXJT7XaECV+Q8HICLI26kuCICMx5XkSQA5eO4KA/zKxwKbU9 vaj05Q0ZFI6w3hX1kksTm9IbnC1jz0XY+dK6PygH7mmAY+ZK+xM1iJ9RBsAlAyhP4zWv rJ78yefQ6lUCN/UIHhn+Bz2c/CVyEi7d/YWQtKmHaXx++rk2uFVtft3TiH+6AMJKWjk6 RnAg== X-Gm-Message-State: AJcUukfDiZtymLFePD+hU63z8oeFhaVbvRQEShoB5iIDykzKBd3hrxX5 5UoIUbQiAK1v/jTuxE0LMVb/Hw== X-Google-Smtp-Source: ALg8bN5KAeFB7fRw9I0sM3uYmmMHb0aP1fwLVBIT3GUqVCOufH/9+FB1eBsxBEsUh33VDxMzA+zH8w== X-Received: by 2002:a62:670f:: with SMTP id b15mr12171472pfc.212.1547164052793; Thu, 10 Jan 2019 15:47:32 -0800 (PST) Received: from [192.168.1.121] (66.29.188.166.static.utbb.net. [66.29.188.166]) by smtp.gmail.com with ESMTPSA id v14sm178237847pgf.3.2019.01.10.15.47.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 10 Jan 2019 15:47:31 -0800 (PST) Subject: Re: [PATCH 15/15] io_uring: add io_uring_event cache hit information To: Jeff Moyer Cc: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org, hch@lst.de, avi@scylladb.com References: <20190110024404.25372-1-axboe@kernel.dk> <20190110024404.25372-16-axboe@kernel.dk> From: Jens Axboe Message-ID: Date: Thu, 10 Jan 2019 16:47:28 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Message-ID: <20190110234728.C0EciJoPYIEa4ER6wW23SbGo8xxzyKR82gB8lXdvLac@z> On 1/10/19 4:12 PM, Jeff Moyer wrote: > Jens Axboe writes: > >> Add hint on whether a read was served out of the page cache, or if it >> hit media. This is useful for buffered async IO, O_DIRECT reads would >> never have this set (for obvious reasons). >> >> If the read hit page cache, cqe->flags will have IOCQE_FLAG_CACHEHIT >> set. > > We may want to hold off on this one until the whole mincore/RWF_NOWAIT > debate is sorted. [1] Definitely, it's why it's separate and at the end of the series. But in reality, this doesn't leak anything that timing doesn't already tell you. So it's kind of a moot point. -- Jens Axboe