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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 E4AFEC2D0DB for ; Thu, 23 Jan 2020 18:31:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBAD32253D for ; Thu, 23 Jan 2020 18:31:51 +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="bRBVYENX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728139AbgAWSbv (ORCPT ); Thu, 23 Jan 2020 13:31:51 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:43052 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727278AbgAWSbv (ORCPT ); Thu, 23 Jan 2020 13:31:51 -0500 Received: by mail-pf1-f195.google.com with SMTP id x6so1914159pfo.10 for ; Thu, 23 Jan 2020 10:31:50 -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=LqCb1Dt+8mE8Agcb/iqdFZzhbVwp04Pt6cT0H4D6ED4=; b=bRBVYENXWp60SUcaoF11dpBkoJCBql2gRZ4VyfCikfWJvaHAA/cJ5AI1rjE8FBH/7R 4Y27VAmrHM8kJfv56gArb5Tk68B4NEnMe6bWgqN1IGXwkjg69uBbx3w06NeYNipNRW0l 58pixsljpnJfZkDnboLZmNO25dV2wOt0LN/tmA0qRI9ojbVymHj1ewAueb1GoIPrIYK0 F7HTw+8Ifj1gMusJIaqU5sRvPTfjqR65G8TSbqv+Tnr8OR9nGkcid3nmgTqtwjkkcoZl e/26jQqCncB1+Itzo0BDb3Oqi0qksRHLbxzdsZ2mvmlXXf7/MT60unpSX0wn/NsYkZtc pIVA== 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=LqCb1Dt+8mE8Agcb/iqdFZzhbVwp04Pt6cT0H4D6ED4=; b=FWfpVLoAAxAXzmgcyIJXvHHVZ+0brQiN7Ghgxu4TqHq8YhuygnwD4dydYumIi9AC6w i020aP/KK9+fDQ31yoznJIeC1whjgO9bBIaYvzDRtF84532AYMfRBKliKND5KwmTTJvb X3i2wY6BGOkBokPdYU37dMf5RS7KpFSNU9i3Ylvlhzd2Ac7HV1ol4uSaQuInmx786gaU tLOrHsOKp+q8RAm4VAbhNMvEPdBNoN3v34lCgM+070XWUzkO9zcb8kjxO0Da09kdNKUw 3WU8YTJsRR8pApcYg5PxHcND59RX9pjKWXnOipquzWAFbZ6DGTBRN4dSjxSgCyepVJLD givQ== X-Gm-Message-State: APjAAAVypEIi3+5quDLs1PpxWdjmNfFIM8W36z61oszUPCBDTPatVbAQ AXFaQzF1xunCuGyEXf/queYzTzJHXRg= X-Google-Smtp-Source: APXvYqygJNTq990y7Czijur2ORNhRHnzVsQiRaBxQJNIhUFa/R3VZxrjI0VS4GOCnri2QJp/Ezz+KA== X-Received: by 2002:a63:4287:: with SMTP id p129mr147630pga.122.1579804310189; Thu, 23 Jan 2020 10:31:50 -0800 (PST) Received: from ?IPv6:2600:380:4562:fb25:b980:6664:b71f:35b5? ([2600:380:4562:fb25:b980:6664:b71f:35b5]) by smtp.gmail.com with ESMTPSA id f81sm3305215pfa.118.2020.01.23.10.31.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Jan 2020 10:31:49 -0800 (PST) Subject: Re: [PATCH 14/17] bcache: back to cache all readahead I/Os To: Coly Li , Michael Lyle Cc: linux-bcache , linux-block@vger.kernel.org, stable References: <20200123170142.98974-1-colyli@suse.de> <20200123170142.98974-15-colyli@suse.de> From: Jens Axboe Message-ID: <31f7f6b4-98ea-3cf6-44cc-a9ba67484eb0@kernel.dk> Date: Thu, 23 Jan 2020 11:31:47 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 1/23/20 10:27 AM, Coly Li wrote: > On 2020/1/24 1:19 上午, Michael Lyle wrote: >> Hi Coly and Jens-- >> >> One concern I have with this is that it's going to wear out >> limited-lifetime SSDs a -lot- faster. Was any thought given to making >> this a tunable instead of just changing the behavior? Even if we have >> an anecdote or two that it seems to have increased performance for >> some workloads, I don't expect it will have increased performance in >> general and it may even be costly for some workloads (it all comes >> down to what is more useful in the cache-- somewhat-recently readahead >> data, or the data that it is displacing). > > Hi Mike, > > Copied. This is good suggestion, I will do it after I back from Lunar > New Year vacation, and submit it with other tested patches in following > v5.6-rc versions. Do you want me to just drop this patch for now from the series? -- Jens Axboe