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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 8FEEEC43387 for ; Fri, 28 Dec 2018 10:50:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 626B320879 for ; Fri, 28 Dec 2018 10:50:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kroah.com header.i=@kroah.com header.b="c5KdxtdA"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="EE1E1t7d" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732061AbeL1KuM (ORCPT ); Fri, 28 Dec 2018 05:50:12 -0500 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:50117 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731657AbeL1KuM (ORCPT ); Fri, 28 Dec 2018 05:50:12 -0500 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id 23521231E0; Fri, 28 Dec 2018 05:50:11 -0500 (EST) Received: from mailfrontend1 ([10.202.2.162]) by compute6.internal (MEProxy); Fri, 28 Dec 2018 05:50:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kroah.com; h= date:from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm2; bh=lVUmVluNZd1NM2JBPvZpUPEHJfv t7kD4SJciWQCcuTc=; b=c5KdxtdADM7yAaP8FT/fgcHueR3GK3uiD8Jbov+Eqwx mypAICO+me55UXbQGx4iNKaL2SfkMVEj0erAWod7Bhq6fV9cpNDWMRFa2gxYgtjj 9dCTh9J4ugja+2HAhkmv/LEWPGe+2+bRIRUNR3Jy4pOSrEVFSE2gjRJ3wTfuHqA7 49gWotVqDO12edAiQeo5U54QV7n/a+lJ5xj3iD8x6ULKqiaq5yaqhqtmAW7kb6aO lugOZp4cg7g6BIBFfTOdStwlTMmuRe3MZkpfDd3vuIwqRBEUOKRon4cM//vE0ozW hgGLFRj/6JBYF/Lf2XOGS/PGWpEBHXreN2zb15hwUXw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=lVUmVl uNZd1NM2JBPvZpUPEHJfvt7kD4SJciWQCcuTc=; b=EE1E1t7d4Qok2zLXiFeaEv Q8TvSMwdjgUiEDn3I9oTqXDeAB27p/PJJpyU/vIZoucB5K0iwxnanko8AsPYaRq4 VSGLXjAJzmZfq8a0hWZelRbf3+9qCg2A0Ds1VTpbmFxPJwCR6IaGpqnrfe5NnRIY k2IQnAiNvLfNHjy9mzkBgI9sU/w2WFlqIGyz80TjrWKX0NtVHhnMzWn1knSOmglo wL/BclIGmuP73P7OawJPpNyI0Gs3l5/zpYzZ/rnPO0MkXilCcwyBKhSh5RG9ZLQY scRTbTYRtuFpR3a8kx/Ikx2XDjFJxL4HacQqcrMGNd0IH3g6mwIq3pyCGX1DfR5A == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedtledrtdehgddvudculddtuddrgedtkedrtddtmd cutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfhuthen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvffukfhfgggtuggjfgesthdtredttdervdenucfhrhhomhepifhrvghg ucfmjfcuoehgrhgvgheskhhrohgrhhdrtghomheqnecukfhppeekfedrkeeirdekledrud dtjeenucfrrghrrghmpehmrghilhhfrhhomhepghhrvghgsehkrhhorghhrdgtohhmnecu vehluhhsthgvrhfuihiivgeptd X-ME-Proxy: Received: from localhost (5356596b.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id 7BB97E4597; Fri, 28 Dec 2018 05:50:09 -0500 (EST) Date: Fri, 28 Dec 2018 11:50:08 +0100 From: Greg KH To: Michal Hocko Cc: Roman Gushchin , Dexuan Cui , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Kernel Team , Shakeel Butt , Johannes Weiner , Tejun Heo , Rik van Riel , Konstantin Khlebnikov , Matthew Wilcox , "Stable@vger.kernel.org" Subject: Re: Will the recent memory leak fixes be backported to longterm kernels? Message-ID: <20181228105008.GB15967@kroah.com> References: <20181102073009.GP23921@dhcp22.suse.cz> <20181102154844.GA17619@tower.DHCP.thefacebook.com> <20181102161314.GF28039@dhcp22.suse.cz> <20181102162237.GB17619@tower.DHCP.thefacebook.com> <20181102165147.GG28039@dhcp22.suse.cz> <20181102172547.GA19042@tower.DHCP.thefacebook.com> <20181102174823.GI28039@dhcp22.suse.cz> <20181102193827.GA18024@castle.DHCP.thefacebook.com> <20181105092053.GC4361@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181105092053.GC4361@dhcp22.suse.cz> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 05, 2018 at 10:21:23AM +0100, Michal Hocko wrote: > On Fri 02-11-18 19:38:35, Roman Gushchin wrote: > > On Fri, Nov 02, 2018 at 06:48:23PM +0100, Michal Hocko wrote: > > > On Fri 02-11-18 17:25:58, Roman Gushchin wrote: > > > > On Fri, Nov 02, 2018 at 05:51:47PM +0100, Michal Hocko wrote: > > > > > On Fri 02-11-18 16:22:41, Roman Gushchin wrote: > > > [...] > > > > > > 2) We do forget to scan the last page in the LRU list. So if we ended up with > > > > > > 1-page long LRU, it can stay there basically forever. > > > > > > > > > > Why > > > > > /* > > > > > * If the cgroup's already been deleted, make sure to > > > > > * scrape out the remaining cache. > > > > > */ > > > > > if (!scan && !mem_cgroup_online(memcg)) > > > > > scan = min(size, SWAP_CLUSTER_MAX); > > > > > > > > > > in get_scan_count doesn't work for that case? > > > > > > > > No, it doesn't. Let's look at the whole picture: > > > > > > > > size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx); > > > > scan = size >> sc->priority; > > > > /* > > > > * If the cgroup's already been deleted, make sure to > > > > * scrape out the remaining cache. > > > > */ > > > > if (!scan && !mem_cgroup_online(memcg)) > > > > scan = min(size, SWAP_CLUSTER_MAX); > > > > > > > > If size == 1, scan == 0 => scan = min(1, 32) == 1. > > > > And after proportional adjustment we'll have 0. > > > > > > My friday brain hurst when looking at this but if it doesn't work as > > > advertized then it should be fixed. I do not see any of your patches to > > > touch this logic so how come it would work after them applied? > > > > This part works as expected. But the following > > scan = div64_u64(scan * fraction[file], denominator); > > reliable turns 1 page to scan to 0 pages to scan. > > OK, 68600f623d69 ("mm: don't miss the last page because of round-off > error") sounds like a good and safe stable backport material. Thanks for this, now queued up. greg k-h