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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 231A6C3B186 for ; Wed, 12 Feb 2020 22:24:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF0F721734 for ; Wed, 12 Feb 2020 22:24:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581546279; bh=6xxtcRGEqLWVVK850kDdT7XB02jgICrdrdzJy8uO9dQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=GkXwzieBEA4BB2ZjpizeV0GLbM9WG4cOJGAtYHDjaaPYBgDyALeGOdE+yL+/mX7CX OQ+0XHb+L/cKODHUtfbU5X5sR9MvgIIauV7GmUwaJiwlwMRljiIVx/rhtFU9gIeSTx fB25IsUOQfOMfwZpzxFDg4OiF9Jx2rcOEaLrSCvQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729199AbgBLWYi (ORCPT ); Wed, 12 Feb 2020 17:24:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:35008 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727791AbgBLWYg (ORCPT ); Wed, 12 Feb 2020 17:24:36 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8C8A82168B; Wed, 12 Feb 2020 22:24:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581546275; bh=6xxtcRGEqLWVVK850kDdT7XB02jgICrdrdzJy8uO9dQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=St4l6sXEZSo9vMcsMXMQVycf8+gdfXbIVc7ALBfuRTNx3DauOg9GOgu4irqF+XsbJ l2GUqSxCouJVMfCmFAOW3cFGpMyOr2PcsTXXHKW5H5bpMzQjx57ctdNgpvuGabsDIc YuG+U46XAngr7rEgwiGIgNvrNQyTvGZ3FQ68w38Q= Date: Wed, 12 Feb 2020 14:24:35 -0800 From: Andrew Morton To: Minchan Kim Cc: Matthew Wilcox , Jan Kara , linux-mm , Josef Bacik , Johannes Weiner , LKML Subject: Re: [PATCH] mm: fix long time stall from mm_populate Message-Id: <20200212142435.0b7e938fe8112fa35fcbcc71@linux-foundation.org> In-Reply-To: <20200212195322.GA83146@google.com> References: <20200211035004.GA242563@google.com> <20200211035412.GR8731@bombadil.infradead.org> <20200211042536.GB242563@google.com> <20200211122323.GS8731@bombadil.infradead.org> <20200211163404.GC242563@google.com> <20200211172803.GA7778@bombadil.infradead.org> <20200211175731.GA185752@google.com> <20200212101804.GD25573@quack2.suse.cz> <20200212174015.GB93795@google.com> <20200212182851.GG7778@bombadil.infradead.org> <20200212195322.GA83146@google.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 12 Feb 2020 11:53:22 -0800 Minchan Kim wrote: > > That's definitely wrong. It'll clear PageReclaim and then pretend it did > > nothing wrong. > > > > return !PageWriteback(page) || > > test_and_clear_bit(PG_reclaim, &page->flags); > > > > Much better, Thanks for the review, Matthew! > If there is no objection, I will send two patches to Andrew. > One is PageReadahead strict, the other is limit retry from mm_populate. With much more detailed changelogs, please! This all seems rather screwy. if a page is under writeback then it is uptodate and we should be able to fault it in immediately.