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=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 606D4C2D0DB for ; Thu, 23 Jan 2020 17:28:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B41221569 for ; Thu, 23 Jan 2020 17:28:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727296AbgAWR2F (ORCPT ); Thu, 23 Jan 2020 12:28:05 -0500 Received: from mx2.suse.de ([195.135.220.15]:35730 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727022AbgAWR2F (ORCPT ); Thu, 23 Jan 2020 12:28:05 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 79C8BAEEE; Thu, 23 Jan 2020 17:28:03 +0000 (UTC) Subject: Re: [PATCH 14/17] bcache: back to cache all readahead I/Os To: Michael Lyle Cc: Jens Axboe , linux-bcache , linux-block@vger.kernel.org, stable References: <20200123170142.98974-1-colyli@suse.de> <20200123170142.98974-15-colyli@suse.de> From: Coly Li Organization: SUSE Labs Message-ID: Date: Fri, 24 Jan 2020 01:27:59 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; 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 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. Thanks. Coly Li [snipped] -- Coly Li