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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75FE3EB64D9 for ; Thu, 6 Jul 2023 12:02:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0D0CE8D0003; Thu, 6 Jul 2023 08:02:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 059D88D0001; Thu, 6 Jul 2023 08:02:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E158B8D0003; Thu, 6 Jul 2023 08:02:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id CB48A8D0001 for ; Thu, 6 Jul 2023 08:02:12 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 884411A0C56 for ; Thu, 6 Jul 2023 12:02:12 +0000 (UTC) X-FDA: 80981048904.20.C3EDAC8 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf10.hostedemail.com (Postfix) with ESMTP id 155BBC0088 for ; Thu, 6 Jul 2023 12:01:47 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Fw9lIpOl; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf10.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1688644908; h=from:from:sender: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=dl3R31sG5o/qvveXTrvTvakzx+epZY7EL41Ub8ppMOk=; b=Zi0wG2DFM/6VhGMbs18r87c/WbmIF+AQOPPzNFXd1dO61Fcsor34zYiEpWTfvfxW20BJVd 6idE8QtN5NN7f8K1rjX8KUJnVnnVfUXq4lkSntLNG3RjdCbN5VqYeSylTedkuAq8jwwzd7 gmfDx3HMJLexIMu/csd4/qpnLdjV9qI= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Fw9lIpOl; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf10.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1688644908; a=rsa-sha256; cv=none; b=SZKyepG4zjuuWTCUKHle36lBPUOe2wVVw5ACntVQTmTnkZY+JeVGdJZdZGVi7fjcEUAm7E 7iMqoi0UMomj55mfexpM9z0mCEbTPetRbk0XRo27Jq7AADQfVhlGNuTiDvyIEF4S6PEkvy t8PwJwSAyCW54hHF8ddIfsRzZ3gB2xQ= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1688644906; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dl3R31sG5o/qvveXTrvTvakzx+epZY7EL41Ub8ppMOk=; b=Fw9lIpOlt7tKR7XKhkMeB414ByLy5Xf5xStdaKJR2lDh5l/ZNTvRCm5cMFmi1WBXu+mMom qIMtEJhRN/pLMrN7XXP/n0F4CQCKu90gaO0L+zCfZ/Pr0W+2B1G/Zw+AeWPW0vOHPauta9 7O1v+ZkJXk1fJCWYIz3cIelig4QJTrY= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-74-Mkpk8fIbOQ6yK1ejk9b_8g-1; Thu, 06 Jul 2023 08:01:44 -0400 X-MC-Unique: Mkpk8fIbOQ6yK1ejk9b_8g-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-314256aedcbso297655f8f.0 for ; Thu, 06 Jul 2023 05:01:43 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688644902; x=1691236902; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=dl3R31sG5o/qvveXTrvTvakzx+epZY7EL41Ub8ppMOk=; b=C8KdWp8WmgkAVEXGlBvxi0yO50Ch1je2ZW9zo4gwSUbU3eH/xxeVGItdyMDOcOMeai yM9JxE5EP8xIzSThZeGQd/1yYh2h/gA0dyGcsvAidr/IEHTLyym0DlYumXsLVtvPSTsN AHhdsl3MORyRvhum0Krzs2MTB66RiDnVjXd0ueQSbjpic8B1nLldFm7xG2rLW5qJwqCK zzMFvMDkNXQilvul/6/EHRcgyouA0wZSmF1srjBKE7N4Rd4rlW0otVBgkZDsDqan/agv 4C4Bi3P8RUseP8vWWNlY47Fs98Aszqd91KjwnMwnYPrz2Wh9ri11AgTIj5notPTtGXlJ AghQ== X-Gm-Message-State: ABy/qLbW/dH+JWiVupyoC2FjRsCXvWAS2J3cnBs5AawrSXjwjP8vIgSM gC0I6E2yXCNwbPAwDjqlS7gY12BbSfFdXEXowkAs7Cs/snFzsZU/qkC6sTGQxzrTL5rKqch+9S7 b+4VvR/FMk9c= X-Received: by 2002:adf:f286:0:b0:313:fd26:6fea with SMTP id k6-20020adff286000000b00313fd266feamr1327917wro.39.1688644902394; Thu, 06 Jul 2023 05:01:42 -0700 (PDT) X-Google-Smtp-Source: APBJJlE31M+FUJfq8JTtI3k5875XjLwapH1JoB6LWZXwQY8KfCzpowxsoaGORlSLUIj6iYqrAUkb3Q== X-Received: by 2002:adf:f286:0:b0:313:fd26:6fea with SMTP id k6-20020adff286000000b00313fd266feamr1327897wro.39.1688644901987; Thu, 06 Jul 2023 05:01:41 -0700 (PDT) Received: from ?IPV6:2a09:80c0:192:0:5dac:bf3d:c41:c3e7? ([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id q24-20020a056000137800b00314172ba213sm1688337wrz.108.2023.07.06.05.01.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Jul 2023 05:01:41 -0700 (PDT) Message-ID: Date: Thu, 6 Jul 2023 14:01:40 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH] mm/ksm: prepare to remove the redundant ksm_merging_pages in procfs To: Nanyong Sun , akpm@linux-foundation.org Cc: xu.xin16@zte.com.cn, wangkefeng.wang@huawei.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20230706094917.588213-1-sunnanyong@huawei.com> <492be1c2-9078-1923-51f9-e01156455ea1@redhat.com> <848fb72a-60a3-bf1d-a091-c25090175eb7@huawei.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <848fb72a-60a3-bf1d-a091-c25090175eb7@huawei.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 155BBC0088 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: ntaasmw355hsjxuy1p6qardk48zrjfn8 X-HE-Tag: 1688644907-584868 X-HE-Meta: U2FsdGVkX1+0IDQw6ljsKbVPsCNmktzij8XHYA5aMmjJ1yEwRYSDdidFbFq61dMY0UO2QGEJzkTiRWNXBeReWCgtp+60oZICFYJEG/8EF/Pdd1BdLLNiR8rrFdLm2Ns2fhzGC1rXaDU9LtDfH0BGR+0hHBt5cQViW3u6ftjIIy659iRoFAyx0EulhOUoMTX4vz2WYB26lZ7U34Z79PxILEA92X32JaJQFaaJKoRvpfuAsRXDhrUI6oz9jCFGiuMo0VGUfENUrS5fWOcn4VMOEDXfxsWyIRysFbMhn17FZtTRiZ+HdoEwL76cRz4+6eFMgwwyphlQdQEUNWOeH6aVCjTGAIfjOxaUFeuy9OrR4XuHZnve+ZiSvTXfAn1YXm+Jx4A6/1RoTRc4OEtl1jtfKCbhqRtJTrFcwCr0U1i3lGjozo7wgqD6UR8L0a6o9zbMqVYcX3LCqmjCWTkoS9mK9rTQbZTEWnTJGXR0X7LW0Jdbft30QsXH0M5TQ/qK3v27iTm+FZeo4sesrHg2T5sNnKMRRz8S7lY/A9lL/NEslDUp0oSib8z6+7yn8Uj7/uDt0ZKnNmovr0JzScmJJDhb1mUKdUrJz+npPkju2clbUSE5+ddCo3XgO09XefOrHAgzHJo4QkfdNYj2/uSzfiz/Pdkwk4j6+vTAf8t17ZP1Fp/Ptrkb2vlsePXmdwmPt8gxN1lRXnsb/9lKg0MTJnFN546ePIT5TE28Js+1V+z+R4zW5dgPLuiQk8ZJ1pcyDH7ifiAbMYyd9COsd9+2gtSeE/5Bk+NKIOuhW852fRHWq0X7HJuviSvd/T2OV8kGls2EGXJcI+oKTVGHdX2s6PN8tve76vmYigbR5ISJzeK8mw0mNBkhYfsEyVYBMMjJfTG+5zjk/VaLCfJ5EPSi3Js3rqhwyNUr3QBedL32OGOmJ7EIWKtwU1UyahbI+HslQbVCKoMGj6WazJ8Uo1BC0g/ s55TWEol sfj0/FRG87dFyqyvjskKr8N8x42Q0f9NYGS7xYQ9OE2McqxVQgAzt1+2lZ8M/3PrviBK6ACLEwgrDRroYkcaixeJjaM//9z6qezKfrHdxwG6f6HhAwNJB/fBqASvS9JR/wlwvlEjZ6Iaa1l0mRq8u1wfrwnOMGFW5DPo+X/Up5ylYJExF4/fAEszT9+NhhajgKd8qeiJflJ2J6hyvOGdXykppYINv9Z7PSoITIzN5ztBYXfpwD/Mr4PvmP4EYPXKX54rnnfUXvKy4GQr75ZCph5S7APHyzmlyYp3DMoUY8pTreTifIIlM0O3Q60pVIJhstpZKeUs4ma6wyPdU1WHLmMNfy202RD75YJqKHinkinRwwtDlIvI641O38tyXsqgvhLx3c4wcdTJx4wla3OauxK/kMn9Adr3qQB+87El5D7sPJ0G4Y+BVb0lqLeW+LpN54yqe11r2PfqtHuhorbBRLQqD5b09kQqGv/CO X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 06.07.23 13:59, Nanyong Sun wrote: > On 2023/7/6 16:55, David Hildenbrand wrote: > >> On 06.07.23 11:49, Nanyong Sun wrote: >>> Since the ksm_merging_pages information already included in >>> /proc//ksm_stat, we could remove /proc//ksm_merging_pages >>> to make the directory more clean, and can save a little bit resources. >>> >>> To delete this interface more smoothly and avoid userspace break, >>> retain this interface temporarily and modify its function to hint >>> users to use ksm_stat instead. >>> >>> Signed-off-by: Nanyong Sun >>> --- >>>   fs/proc/base.c | 9 +-------- >>>   1 file changed, 1 insertion(+), 8 deletions(-) >>> >>> diff --git a/fs/proc/base.c b/fs/proc/base.c >>> index eb2e498e3b8d..d080c58cbe6c 100644 >>> --- a/fs/proc/base.c >>> +++ b/fs/proc/base.c >>> @@ -3189,14 +3189,7 @@ static int proc_pid_patch_state(struct >>> seq_file *m, struct pid_namespace *ns, >>>   static int proc_pid_ksm_merging_pages(struct seq_file *m, struct >>> pid_namespace *ns, >>>                   struct pid *pid, struct task_struct *task) >>>   { >>> -    struct mm_struct *mm; >>> - >>> -    mm = get_task_mm(task); >>> -    if (mm) { >>> -        seq_printf(m, "%lu\n", mm->ksm_merging_pages); >>> -        mmput(mm); >>> -    } >>> - >>> +    seq_puts(m, "please use /proc//ksm_stat instead\n"); >>>       return 0; >>>   } >>>   static int proc_pid_ksm_stat(struct seq_file *m, struct >>> pid_namespace *ns, >> >> >> Why do we care so much about removing 15 simple LOC? That change here >> will already mess with user space. >> >> Sorry, but IMHO it's all not worth the churn. >> > We do not pay attention to these 15 LOC. We pay more attention to the > redundant interface under procfs. > > This interface is used by developers and has a short history. Therefore, > changing it now has no big impact. > Again, already 1 year old. And returning garbage instead of ripping it out might be even nastier. -- Cheers, David / dhildenb