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=-6.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 855B6C43461 for ; Thu, 10 Sep 2020 22:29:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D63BB21D91 for ; Thu, 10 Sep 2020 22:29:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=soleen.com header.i=@soleen.com header.b="anjWYdkL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D63BB21D91 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=soleen.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 19C2A6B009D; Thu, 10 Sep 2020 18:29:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 171896B009E; Thu, 10 Sep 2020 18:29:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0AF4A8E0001; Thu, 10 Sep 2020 18:29:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0105.hostedemail.com [216.40.44.105]) by kanga.kvack.org (Postfix) with ESMTP id E8D506B009D for ; Thu, 10 Sep 2020 18:29:07 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id AEC992481 for ; Thu, 10 Sep 2020 22:29:07 +0000 (UTC) X-FDA: 77248593534.21.bread63_55038d1270e9 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id 6D50E180442C3 for ; Thu, 10 Sep 2020 22:29:07 +0000 (UTC) X-HE-Tag: bread63_55038d1270e9 X-Filterd-Recvd-Size: 4422 Received: from mail-ed1-f66.google.com (mail-ed1-f66.google.com [209.85.208.66]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Thu, 10 Sep 2020 22:29:06 +0000 (UTC) Received: by mail-ed1-f66.google.com with SMTP id n22so7998883edt.4 for ; Thu, 10 Sep 2020 15:29:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RemceQYpfwTMZI7GvmZz01XxDX57S6jy8i4dk7JJMAA=; b=anjWYdkLN4gIBWfzcuYV32XXsJNNWFlJieTFfjQBtCxv7TQFjfdJIYWsKDwJv67SJt X3lRg3LAFe3yemCNMT3YNeSLRgw9zEjXIH6bER9PF3Y6qiUSYAx52hv82P/TWh+y59Xy /xcdM7RHlcTX1Em272Zhy/29KdOtrFqkATOH6IUIBShC0a2Ix2R4+glwUOTbMh5/n4VQ V6j9rcO961M8qh6Q/5MeOjV0cnZl78WXT+SfWk/5rBmUJZmzR7iB4hP9O29636iNsO7k +N99UIYyS2wwaNbrUwZ047GZ1Tku8kpFLfNbown9eZV2HEX5SA7NyvtWfsI7BRXWNmVb Ux0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RemceQYpfwTMZI7GvmZz01XxDX57S6jy8i4dk7JJMAA=; b=kGsV38h5GbCbqtKKqGWAkHa2XQEBiZgoEaMmGbE8f6mF6k0VAC69ZZU4xn/z+ifcZZ JK9BN4vZnsiV58DVcpNom+GpxMo0mNcdSeFsyqJy9Y0nUQeDYC5Tdp7Jq1QGRi809mH3 yiSrUgXCaXRlh+FTmk/6NFFoY/SKuVKAT0uydAbH+AtjOy8/TbA5Bpt0HZIRbbqzeoCv 8tuPLdsuQ6LTSBYdnLVQSSFog6z1EvU5q7hWO42UyXeNDwEggpSJGXG/HSbhE2pLh+iM omtXzvHtFtOEX+YYrelpvrMPRpgwRcBql8nafLewoXKTFbUXw/QT9ZHVGGM3ivLao4QC pjzA== X-Gm-Message-State: AOAM5300ZZuyMAZgwSd9Nrc9jIgw7g45lifnibywjzVOY6Cj/cd2pdM9 BT1M1PzyfA9Www2EseQ+LoBHk0m1+CgKzuAives+EA== X-Google-Smtp-Source: ABdhPJxByr+VKSmMGcDLHRgmPssigxjSr+wMirCzz5iMdKine6/IsGRjO23WjHzNFw4NLOMWaVGp/bAiryc5Pa+xxVs= X-Received: by 2002:a05:6402:1544:: with SMTP id p4mr11588205edx.346.1599776945630; Thu, 10 Sep 2020 15:29:05 -0700 (PDT) MIME-Version: 1.0 References: <1599770859-14826-1-git-send-email-vijayb@linux.microsoft.com> <20200910220145.5j7iogqulmvg5vr6@black.fi.intel.com> In-Reply-To: <20200910220145.5j7iogqulmvg5vr6@black.fi.intel.com> From: Pavel Tatashin Date: Thu, 10 Sep 2020 18:28:29 -0400 Message-ID: Subject: Re: [[PATCH]] mm: khugepaged: recalculate min_free_kbytes after memory hotplug as expected by khugepaged To: "Kirill A. Shutemov" Cc: Vijay Balakrishna , Andrew Morton , Oleg Nesterov , Song Liu , Andrea Arcangeli , Allen Pais , LKML , linux-mm Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 6D50E180442C3 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000006, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Kirill, On Thu, Sep 10, 2020 at 6:01 PM Kirill A. Shutemov wrote: > > On Thu, Sep 10, 2020 at 01:47:39PM -0700, Vijay Balakrishna wrote: > > When memory is hotplug added or removed the min_free_kbytes must be > > recalculated based on what is expected by khugepaged. Currently > > after hotplug, min_free_kbytes will be set to a lower default and higher > > default set when THP enabled is lost. This leaves the system with small > > min_free_kbytes which isn't suitable for systems especially with network > > intensive loads. Typical failure symptoms include HW WATCHDOG reset, > > soft lockup hang notices, NETDEVICE WATCHDOG timeouts, and OOM process > > kills. > > > > Fixes: f000565adb77 ("thp: set recommended min free kbytes") > > > > Signed-off-by: Vijay Balakrishna > > Cc: stable@vger.kernel.org > > NAK. It would override min_free_kbytes set by user. Hi Kirill, Thank you for looking into this. How is this different from when khugepaged modifies it? echo always >/sys/kernel/mm/transparent_hugepage/enabled Which results in: start_stop_khugepaged set_recommended_min_free_kbytes Which will also adjust min_free_kbytes according to hugepaged requirement? This bug that Vijay described is another hot-plug related issue that we have found on our system where we perform memory hot add and hot remove on every reboot. Thank you, Pasha