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 CB73CC47074 for ; Thu, 4 Jan 2024 17:33:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2E1C76B0309; Thu, 4 Jan 2024 12:33:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 292706B030A; Thu, 4 Jan 2024 12:33:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 15B2A6B030C; Thu, 4 Jan 2024 12:33:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 04CC06B0309 for ; Thu, 4 Jan 2024 12:33:29 -0500 (EST) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id B5240A09D0 for ; Thu, 4 Jan 2024 17:33:28 +0000 (UTC) X-FDA: 81642325296.04.E1A3FE4 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) by imf11.hostedemail.com (Postfix) with ESMTP id 5AABA4002E for ; Thu, 4 Jan 2024 17:33:26 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=FUfmc3Qh; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=Q1CdOL97; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=sKngIZFV; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=KYUhj4jo; spf=pass (imf11.hostedemail.com: domain of jack@suse.cz designates 195.135.223.130 as permitted sender) smtp.mailfrom=jack@suse.cz; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1704389606; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=FsRJvLQnecTvHGtb1HFyEgtgGzgqO3i0oqXp5vlKPWI=; b=YlJ6UdKbrahOET8KNoxQotiJcxxjkuuAq3ANn8ofDOaMcjMIZOx4iYTwTZQn8XKZ/cEGpZ 2aZFTQFdoAY12kmNceNBWXa8wOtm920TzGiCqlsk6EyaNEx5ClyGri67bnWV8RtTpPFKEi cAUtqJeUbAG6VVJpAwDqaljVOkCtzqQ= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1704389606; a=rsa-sha256; cv=none; b=wbQd7XmrYM/MKDiTvTHwx6Fre7Eq61mHd57LsI5ZjwGsA7Zh4YIHnEidf9ocHbgV9OGrzJ P4KArmfCJ8eNo4aMGzIrEThMMgZ/KkZSCxGQUQE9g/reV4XfBaGL24tfUHFbkFFN3oXDvC Jl/LpESSY+QCAd8azl+XkXIaBoT1fag= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=FUfmc3Qh; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=Q1CdOL97; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=sKngIZFV; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=KYUhj4jo; spf=pass (imf11.hostedemail.com: domain of jack@suse.cz designates 195.135.223.130 as permitted sender) smtp.mailfrom=jack@suse.cz; dmarc=none Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id E61EE220E3; Thu, 4 Jan 2024 17:33:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1704389604; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FsRJvLQnecTvHGtb1HFyEgtgGzgqO3i0oqXp5vlKPWI=; b=FUfmc3Qh0MAGpw9hE1UCALTro4oNQzSromnIwoyARtAD67o1EK5qtJ8XnfjGZJ0Ckmcyin 2GvHWi0pkSshwyWmpxnTQxWyE7brQqXjnRdKZ0cJI1hjYbRwYLGOkgEVJniy8RRtZtWALE tqZFBriSBgGuJbmgwggtW2xw//SSWjM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1704389604; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FsRJvLQnecTvHGtb1HFyEgtgGzgqO3i0oqXp5vlKPWI=; b=Q1CdOL97nApponZ0+Gy2YpFJyPecVMp/76l3qZN6oV6rZSpTGv9AcQbZOzdwOVKQBMAHW+ VblZXIeMwLgoNqBA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1704389603; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FsRJvLQnecTvHGtb1HFyEgtgGzgqO3i0oqXp5vlKPWI=; b=sKngIZFV37auVSfq3UB+l3+cObj5PhuLlhL1lIYtrTEr26ZSQ9JJKbk1nM2CSW2A+VA6mt mZ7xHp0jPIyF65C0y5irRidvaZujqZc9iFkv8qqHkhNQm0uPus/gYobdW4T8IfhQSh07af SM3oACnpH9apOP8kiMiM28EHRYvyk0Y= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1704389603; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FsRJvLQnecTvHGtb1HFyEgtgGzgqO3i0oqXp5vlKPWI=; b=KYUhj4joWBSk58EDoOrE0oqoK+ObIbf49vSBv976EsBlWrHkhl5lHbNSqx2rH3n4TKe0+8 vjuLAiEKwSSzuPDA== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id D4B1213722; Thu, 4 Jan 2024 17:33:23 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id FLLiM+PrlmW5bwAAD6G6ig (envelope-from ); Thu, 04 Jan 2024 17:33:23 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 650E8A07EF; Thu, 4 Jan 2024 18:33:19 +0100 (CET) Date: Thu, 4 Jan 2024 18:33:19 +0100 From: Jan Kara To: Jingbo Xu Cc: shr@devkernel.io, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, joseph.qi@linux.alibaba.com, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, willy@infradead.org Subject: Re: [PATCH v3 1/2] mm: fix arithmetic for bdi min_ratio Message-ID: <20240104173319.a7ui5uh4jde5jan4@quack3> References: <20231219142508.86265-1-jefflexu@linux.alibaba.com> <20231219142508.86265-2-jefflexu@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231219142508.86265-2-jefflexu@linux.alibaba.com> X-Rspamd-Queue-Id: 5AABA4002E X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: szzqhddmu6cp8i54gp9191np8xom1enb X-HE-Tag: 1704389606-27195 X-HE-Meta: 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 zTS51Lae 8AQXwDX64pmAdEAtWLhaWW5kiXVTCFvm9arGSi54azCvSsH1nMFQBoC4eEFm2MstZWbiXX7prGZjSvYR+twuMe9AClvfjNpPUT3H7I7PrihzmTYx18GDj6x0YFFOyfPZMms5voVkmSgW7E101MejQ5cCzUEQcgLjZ64YqkslH1hbC3CBK7/zLpQIzJgDKId6HiFUW2LDFOZ93tt3x9m0mPqTK07xfEZ58CwZTCguOGTrpHRIkeHLfFb8VqRMURvcWC9ecxJk2imyHdExbRHdXn7yZhGWM1UoqDzFeDasoWkxHGe2dLlqTFGqlDsBVfSvSycK7Wx5dfvTgd8z+o6PcFJ3EyibQqIq539PG 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: List-Subscribe: List-Unsubscribe: On Tue 19-12-23 22:25:07, Jingbo Xu wrote: > Since now bdi->min_ratio is part per million, fix the wrong arithmetic. > Otherwise it will fail with -EINVAL when setting a reasonable min_ratio, > as it tries to set min_ratio to (min_ratio * BDI_RATIO_SCALE) in > percentage unit, which exceeds 100% anyway. > > # cat /sys/class/bdi/253\:0/min_ratio > 0 > # cat /sys/class/bdi/253\:0/max_ratio > 100 > # echo 1 > /sys/class/bdi/253\:0/min_ratio > -bash: echo: write error: Invalid argument > > Fixes: 8021fb3232f2 ("mm: split off __bdi_set_min_ratio() function") > Reported-by: Joseph Qi > Signed-off-by: Jingbo Xu Looks good. Feel free to add: Reviewed-by: Jan Kara Honza > --- > mm/page-writeback.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index ee2fd6a6af40..2140382dd768 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -692,7 +692,6 @@ static int __bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ra > > if (min_ratio > 100 * BDI_RATIO_SCALE) > return -EINVAL; > - min_ratio *= BDI_RATIO_SCALE; > > spin_lock_bh(&bdi_lock); > if (min_ratio > bdi->max_ratio) { > -- > 2.19.1.6.gb485710b > > -- Jan Kara SUSE Labs, CR