From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id 019718E0095 for ; Tue, 11 Dec 2018 11:39:55 -0500 (EST) Received: by mail-ed1-f72.google.com with SMTP id z10so7217300edz.15 for ; Tue, 11 Dec 2018 08:39:54 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id gv13-v6si1615985ejb.271.2018.12.11.08.39.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 Dec 2018 08:39:53 -0800 (PST) Date: Tue, 11 Dec 2018 17:39:52 +0100 From: Jan Kara Subject: Re: [PATCH] mm, memcg: fix reclaim deadlock with writeback Message-ID: <20181211163952.GB4020@quack2.suse.cz> References: <20181211132645.31053-1-mhocko@kernel.org> <20181211151542.2rjti4glj75honje@kshutemo-mobl1> <20181211162149.GL1286@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181211162149.GL1286@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: "Kirill A. Shutemov" , Andrew Morton , Liu Bo , Jan Kara , Dave Chinner , Theodore Ts'o , Johannes Weiner , Vladimir Davydov , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, LKML On Tue 11-12-18 17:21:49, Michal Hocko wrote: > On Tue 11-12-18 18:15:42, Kirill A. Shutemov wrote: > > For instance, DAX page fault will setup page table entry on its own and > > return VM_FAULT_NOPAGE. It uses vmf_insert_mixed() to setup the page table > > and ignores your pre-allocated page table. > > Does this happen with a page locked and with __GFP_ACCOUNT allocation. I > am not familiar with that code but I do not see it from a quick look. DAX has no page to lock and also no writeback to do so the deadlock isn't really possible when DAX is in use... Honza -- Jan Kara SUSE Labs, CR