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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBEA7C433FE for ; Tue, 11 Oct 2022 02:31:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229538AbiJKCbT (ORCPT ); Mon, 10 Oct 2022 22:31:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229486AbiJKCbQ (ORCPT ); Mon, 10 Oct 2022 22:31:16 -0400 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D3A444545 for ; Mon, 10 Oct 2022 19:31:16 -0700 (PDT) Received: by mail-pl1-x644.google.com with SMTP id z20so11926741plb.10 for ; Mon, 10 Oct 2022 19:31:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=9RiYkkaouCeju2FK9kFYRxZwyL4FwNeYIrqFqqh+8sc=; b=mr1k+gWlKAo9bIQwNZpgToG2BhZrpjLTAAlzhQff6okpkL0TUG3ii+mwI/k1m7awkz ejbIaL5o1MiVuEwa4xhBF08UlDVABuuDTGiEbLqKAmV7t7yJ74nr4TVfN496TdGH1a4p CAeonB7ZoeeuGXq8tR14Auvf9qYfCo5pzw6GQjum9KxjbFJs8hSrP8zuvxZ4/md0k8GN 0vy22ugu5qUMiT7jHDSKcT6EmWeMryqkQfcDeXCgJDHhv3n/aaHBofXmUFI14zcFBEP/ /WCPaOXdBPuXyKxl076yqq3Mr/n79xF3sj7UpKg/8g9TgyUJcbzIwpjpy1Wh76qMFP2A EUrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=9RiYkkaouCeju2FK9kFYRxZwyL4FwNeYIrqFqqh+8sc=; b=LJoYC5wWdkHU2hrSvwOPAOiQz2GRZ1KCsAgcaPhTEIEL2na2LD4AQyZfLAE4/7rfQh 70rExAqHhwsRxknqjlqGZfINOwe906ITil4+OmEJmgMlAijUg/nSUrxvz8hUoX+MpErA 00R7lfoOiuWzFzw3dj0FX6rb82+ZP9xryU9L9SOt5G4mdTOSks/1AlQGDMGjecCGl5zU ZmyEtTJjpUjeqT3dKY7+JgXyvGv4wdf9WkxEGP2nVimddhiCQf4LCHpHzP0F/d+bnfQ8 IeQxRE8/v01kJNCfB5RTX8nQw7OUU8qWndzqPn1nPfe5PftdCsRkZIqdKxyjzdppTRPP pJ+A== X-Gm-Message-State: ACrzQf3+qJCWIvJo1uTsSmPX+cRWupuFm8P4gykn1koeJmgt/DcxyEn+ vN9mYMQxrMyaFg3/2J+lw6U= X-Google-Smtp-Source: AMsMyM4yADhpfCygecGf0o3F0Rw6HAS3QBM5Dzy6J5SvS3nnfN5iYTSMDY2ObyFxDUv0RapjAUfoQQ== X-Received: by 2002:a17:902:d70a:b0:178:5d52:9e41 with SMTP id w10-20020a170902d70a00b001785d529e41mr22226129ply.0.1665455475790; Mon, 10 Oct 2022 19:31:15 -0700 (PDT) Received: from localhost.localdomain ([193.203.214.57]) by smtp.gmail.com with ESMTPSA id p4-20020a637f44000000b0043954df3162sm7073872pgn.10.2022.10.10.19.31.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Oct 2022 19:31:14 -0700 (PDT) From: xu xin X-Google-Original-From: xu xin To: imbrenda@linux.ibm.com Cc: akpm@linux-foundation.org, david@redhat.com, jiang.xuexin@zte.com.cn, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ran.xiaokai@zte.com.cn, xu.xin.sc@gmail.com, xu.xin16@zte.com.cn, yang.yang29@zte.com.cn Subject: Re: [PATCH v2 0/5] ksm: support tracking KSM-placed zero-pages Date: Tue, 11 Oct 2022 02:31:09 +0000 Message-Id: <20221011023109.322501-1-xu.xin16@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221010154248.1ee86294@p-imbrenda> References: <20221010154248.1ee86294@p-imbrenda> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > >> Hello, Thanks for your reply. >> >> > >> >why are you trying so hard to fix something that is not broken? >> >> Actually, it breaks the definition of unmerge, though it's usually not a big >> problem. >> > >> >can't you just avoid using use_zero_pages? >> >> use_zero_pages is good, not just because of cache colouring as described in doc, >> but also because use_zero_pages can accelerate merging empty pages when there >> are plenty of empty pages (full of zeros) as the time of page-by-page comparision >> (unstable_tree_search_insert) is saved. > >interesting, this is some useful information that you could have written >in the cover letter and/or commit messages, to explain why you are >proposing these changes :) Yes. I have done it in v3. Thanks. > >> >> > >> >why is it so important to know how many zero pages have been merged? >> >and why do you want to unmerge them? >> >> Zero pages may be the most common merged pages in actual environment(not only VM but > >also interesting information, which you could also have written in the >cover letter and/or commit messages > >> also including other application like containers). Sometimes customers (app developers) >> are very interested in how many non-zero-pages are actually merged in their apps. >> >> > >> >the important thing is that the sysadmin knows how much memory would be >> >needed to do the unmerge, and that information is already there. >> > >> >> I think it's about chicken-and-egg problem. >> >> >> Anyway, thanks for your reply. >>