From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753960AbbHCOGi (ORCPT ); Mon, 3 Aug 2015 10:06:38 -0400 Received: from mga14.intel.com ([192.55.52.115]:8720 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751971AbbHCOGg (ORCPT ); Mon, 3 Aug 2015 10:06:36 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,601,1432623600"; d="scan'208";a="618278976" Message-ID: <55BF7568.1030502@intel.com> Date: Mon, 03 Aug 2015 07:06:32 -0700 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: "Wang, Biao" , "gregkh@linuxfoundation.org" , "arve@android.com" , "riandrews@android.com" CC: "devel@driverdev.osuosl.org" , "linux-kernel@vger.kernel.org" , "Zhang, Di" , "Li, Fei" , "dan.carpenter@oracle.com" , "joe@perches.com" Subject: Re: [PATCH V2] staging: android: lowmemorykiller: imporve lmk to avoid deadlock issue References: <09CB0B4607EB8F4DB7E0BE3B06BFBD051DA2E849@SHSMSX101.ccr.corp.intel.com> In-Reply-To: <09CB0B4607EB8F4DB7E0BE3B06BFBD051DA2E849@SHSMSX101.ccr.corp.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/02/2015 10:53 PM, Wang, Biao wrote: > Consider the following case: > Task A trigger lmk with a lock held, while task B try to > get this lock, but unfortunately B is the very culprit task lmk select to > kill. Then B will never be killed, and A will forever select B to kill. > Such dead lock will trigger softlock up issue. It would be interesting to have some actual data about where this helps. For instance, which locks does this happen on? What kind of allocation? Also, we apparently _do_ mark a lowmemorykiller victim as an oom victim and let them use memory reserves. Why does that not allow the allocation to complete at least long enough to get the kill signal to the victim?