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=-18.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL autolearn=ham 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 35671C43461 for ; Wed, 16 Sep 2020 19:18:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 62BB02075E for ; Wed, 16 Sep 2020 19:18:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="TE04mFt3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 62BB02075E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 76D8890000C; Wed, 16 Sep 2020 15:18:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 71C94900007; Wed, 16 Sep 2020 15:18:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 60B4E90000C; Wed, 16 Sep 2020 15:18:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0125.hostedemail.com [216.40.44.125]) by kanga.kvack.org (Postfix) with ESMTP id 48531900007 for ; Wed, 16 Sep 2020 15:18:16 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 07AC31E0A for ; Wed, 16 Sep 2020 19:18:16 +0000 (UTC) X-FDA: 77269885392.04.cap39_1b044382711c Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin04.hostedemail.com (Postfix) with ESMTP id D14FC800CDBD for ; Wed, 16 Sep 2020 19:18:15 +0000 (UTC) X-HE-Tag: cap39_1b044382711c X-Filterd-Recvd-Size: 4405 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Wed, 16 Sep 2020 19:18:15 +0000 (UTC) Received: from [192.168.0.121] (unknown [209.134.121.133]) by linux.microsoft.com (Postfix) with ESMTPSA id C347C20B7178; Wed, 16 Sep 2020 12:18:13 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com C347C20B7178 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1600283894; bh=16V0MyC5Nylnc0p/3+ujIlxV7WalEW8tyaMt/ccOWNo=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=TE04mFt30GIcedYweK0xVeKcVTITE8HaMpVCve7+Ex48Fmg1lTkWRqdr9ZP1WW95b NPbyr4eMoMFrCQYgQ02NSFOvT647nlsRG2FsC7bvYXyNi/rUszJUyJnLP9rJPSs5XH 8GTVnWVenWAWJ1bjOTfn7/REIOhf9OGF3je5CYXw= Subject: Re: [v2 2/2] mm: khugepaged: avoid overriding min_free_kbytes set by user To: Michal Hocko Cc: Andrew Morton , "Kirill A. Shutemov" , Oleg Nesterov , Song Liu , Andrea Arcangeli , Pavel Tatashin , Allen Pais , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <1600204258-13683-1-git-send-email-vijayb@linux.microsoft.com> <1600204258-13683-2-git-send-email-vijayb@linux.microsoft.com> <20200916075900.GE18998@dhcp22.suse.cz> From: Vijay Balakrishna Message-ID: <7f4816ce-cdb0-b549-c94b-66328b65a85d@linux.microsoft.com> Date: Wed, 16 Sep 2020 12:18:12 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.2.2 MIME-Version: 1.0 In-Reply-To: <20200916075900.GE18998@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: D14FC800CDBD X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 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 9/16/2020 12:59 AM, Michal Hocko wrote: > On Tue 15-09-20 14:10:58, Vijay Balakrishna wrote: >> set_recommended_min_free_kbytes need to honor min_free_kbytes set by the >> user. Post start-of-day THP enable or memory hotplug operations can >> lose user specified min_free_kbytes, in particular when it is higher than >> calculated recommended value. Also modifying "recommended_min" variable >> type to "int" from "unsigned long" to avoid undesired result noticed >> during testing. It is due to comparing "unsigned long" with "int" type. >> >> Signed-off-by: Vijay Balakrishna >> Cc: stable@vger.kernel.org >> Reviewed-by: Pavel Tatashin >> --- >> mm/khugepaged.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/mm/khugepaged.c b/mm/khugepaged.c >> index 4f7107476a6f..b4b753ba411a 100644 >> --- a/mm/khugepaged.c >> +++ b/mm/khugepaged.c >> @@ -2253,7 +2253,7 @@ static void set_recommended_min_free_kbytes(void) >> { >> struct zone *zone; >> int nr_zones = 0; >> - unsigned long recommended_min; >> + int recommended_min; >> >> for_each_populated_zone(zone) { >> /* >> @@ -2280,12 +2280,12 @@ static void set_recommended_min_free_kbytes(void) >> >> /* don't ever allow to reserve more than 5% of the lowmem */ >> recommended_min = min(recommended_min, >> - (unsigned long) nr_free_buffer_pages() / 20); >> + (int) nr_free_buffer_pages() / 20); > > nr_free_buffer_pages can oveflow in int on very large machines. Good point. I will address it. > >> recommended_min <<= (PAGE_SHIFT-10); >> >> - if (recommended_min > min_free_kbytes) { >> + if (recommended_min > user_min_free_kbytes) { > > This can decrease the size theoretically. Because user_min_free_kbytes > is -1 by default and recommended_min might be <= min_free_kbytes. > > You need to check both. Also can we make user_min_free_kbytes 0 by > default? From a quick look, nobody should really care. Let me rework. Thanks, Vijay > >> if (user_min_free_kbytes >= 0) >> - pr_info("raising min_free_kbytes from %d to %lu to help transparent hugepage allocations\n", >> + pr_info("raising min_free_kbytes from %d to %d to help transparent hugepage allocations\n", >> min_free_kbytes, recommended_min); >> >> min_free_kbytes = recommended_min; >> -- >> 2.28.0 >> >