From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f42.google.com (mail-wm0-f42.google.com [74.125.82.42]) by kanga.kvack.org (Postfix) with ESMTP id 8B3936B0038 for ; Wed, 25 Nov 2015 10:45:17 -0500 (EST) Received: by wmuu63 with SMTP id u63so143237381wmu.0 for ; Wed, 25 Nov 2015 07:45:17 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id ej8si35441303wjd.85.2015.11.25.07.45.16 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 25 Nov 2015 07:45:16 -0800 (PST) Subject: Re: [PATCH] vmscan: do not throttle kthreads due to too_many_isolated References: <1448465801-3280-1-git-send-email-vdavydov@virtuozzo.com> From: Vlastimil Babka Message-ID: <5655D789.80201@suse.cz> Date: Wed, 25 Nov 2015 16:45:13 +0100 MIME-Version: 1.0 In-Reply-To: <1448465801-3280-1-git-send-email-vdavydov@virtuozzo.com> Content-Type: text/plain; charset=iso-8859-2 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vladimir Davydov , Andrew Morton Cc: Johannes Weiner , Michal Hocko , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org On 11/25/2015 04:36 PM, Vladimir Davydov wrote: > Block device drivers often hand off io request processing to kernel > threads (example: device mapper). If such a thread calls kmalloc, it can > dive into direct reclaim path and end up waiting for too_many_isolated > to return false, blocking writeback. This can lead to a dead lock if the Shouldn't such allocation lack __GFP_IO to prevent this and other kinds of deadlocks? And/or have mempools? PF_KTHREAD looks like a big hammer to me that will solve only one potential problem... -- 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