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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48350C43334 for ; Mon, 13 Jun 2022 15:06:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244366AbiFMPF7 (ORCPT ); Mon, 13 Jun 2022 11:05:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1386392AbiFMPFg (ORCPT ); Mon, 13 Jun 2022 11:05:36 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C4ACF7499; Mon, 13 Jun 2022 05:11:25 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id ED1C71F38A; Mon, 13 Jun 2022 12:11:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1655122279; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cWi4yPYQYuWcLCZhlzRL/FUwfVjRk7PfFZtsphXFstQ=; b=fWc9Ypl2KcwfmmeUMR5vxJsHU3nImiAo3Pbtm/FripjpX/mp8Fjs3Rh1gZ6Tn3ex0cZ3W+ 0OvfKRLBxncV3yGLDHAgrGqvdZlefo3rLxodVymu5Y4osdFhZqLOhmsWXnI11DWNlx/VZ0 h9lRYJlBhcSh3hyTWiqlBbym/yTUmaw= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 66AB32C141; Mon, 13 Jun 2022 12:11:18 +0000 (UTC) Date: Mon, 13 Jun 2022 14:11:17 +0200 From: Michal Hocko To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: Christian =?iso-8859-1?Q?K=F6nig?= , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-tegra@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, alexander.deucher@amd.com, daniel@ffwll.ch, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, hughd@google.com, andrey.grodzovsky@amd.com Subject: Re: [PATCH 03/13] mm: shmem: provide oom badness for shmem files Message-ID: References: <3f7d3d96-0858-fb6d-07a3-4c18964f888e@gmail.com> <2e7e050e-04eb-0c0a-0675-d7f1c3ae7aed@amd.com> <288528c3-411e-fb25-2f08-92d4bb9f1f13@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 13-06-22 13:50:28, Christian König wrote: > Am 13.06.22 um 09:45 schrieb Michal Hocko: > > On Sat 11-06-22 10:06:18, Christian König wrote: > > > Am 10.06.22 um 16:16 schrieb Michal Hocko: [...] > > > Alternative I could try to track the "owner" of a buffer (e.g. a shmem > > > file), but then it can happen that one processes creates the object and > > > another one is writing to it and actually allocating the memory. > > If you can enforce that the owner is really responsible for the > > allocation then all should be fine. That would require MAP_POPULATE like > > semantic and I suspect this is not really feasible with the existing > > userspace. It would be certainly hard to enforce for bad players. > > I've tried this today and the result was: "BUG: Bad rss-counter state > mm:000000008751d9ff type:MM_FILEPAGES val:-571286". > > The problem is once more that files are not informed when the process > clones. So what happened is that somebody called fork() with an mm_struct > I've accounted my pages to. The result is just that we messed up the > rss_stats and  the the "BUG..." above. > > The key difference between normal allocated pages and the resources here is > just that we are not bound to an mm_struct in any way. It is not really clear to me what exactly you have tried. -- Michal Hocko SUSE Labs