From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id D401C6B0007 for ; Mon, 26 Feb 2018 09:28:41 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id w10so11732055wrg.2 for ; Mon, 26 Feb 2018 06:28:41 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 90si4642506wrq.373.2018.02.26.06.28.40 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 26 Feb 2018 06:28:40 -0800 (PST) Date: Mon, 26 Feb 2018 15:28:39 +0100 From: Michal Hocko Subject: Re: Hangs in balance_dirty_pages with arm-32 LPAE + highmem Message-ID: <20180226142839.GB16842@dhcp22.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Laura Abbott Cc: Linux-MM , linux-block@vger.kernel.org On Fri 23-02-18 11:51:41, Laura Abbott wrote: > Hi, > > The Fedora arm-32 build VMs have a somewhat long standing problem > of hanging when running mkfs.ext4 with a bunch of processes stuck > in D state. This has been seen as far back as 4.13 but is still > present on 4.14: > [...] > This looks like everything is blocked on the writeback completing but > the writeback has been throttled. According to the infra team, this problem > is _not_ seen without LPAE (i.e. only 4G of RAM). I did see > https://patchwork.kernel.org/patch/10201593/ but that doesn't seem to > quite match since this seems to be completely stuck. Any suggestions to > narrow the problem down? How much dirtyable memory does the system have? We do allow only lowmem to be dirtyable by default on 32b highmem systems. Maybe you have the lowmem mostly consumed by the kernel memory. Have you tried to enable highmem_is_dirtyable? -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org