From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753633AbaIWEtY (ORCPT ); Tue, 23 Sep 2014 00:49:24 -0400 Received: from mx1.mxmail.xiaomi.com ([58.68.235.87]:7152 "EHLO mx1.mxmail.xiaomi.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752876AbaIWEtW (ORCPT ); Tue, 23 Sep 2014 00:49:22 -0400 From: =?gb2312?B?1uy71A==?= To: Greg KH CC: "rientjes@google.com" , "vinayakm.list@gmail.com" , "weijie.yang@samsung.com" , "devel@driverdev.osuosl.org" , "linux-kernel@vger.kernel.org" , "teawater@gmail.com" Subject: Re: [PATCH] Fix the issue that lowmemkiller fell into a cycle that try to kill a task Thread-Topic: [PATCH] Fix the issue that lowmemkiller fell into a cycle that try to kill a task Thread-Index: AQHP1toi3qW7tRqemUGYwU3B97qppQ== Date: Tue, 23 Sep 2014 04:48:55 +0000 Message-ID: References: <1411441029-8428-1-git-send-email-zhuhui@xiaomi.com> <20140923041738.GA6779@kroah.com> Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [106.37.216.50] x-esetresult: clean, is OK x-esetid: B888893E9A6C9E31E8C8D1 Content-Type: text/plain; charset="gb2312" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id s8N4nSbP001122 On 09/23/14 12:18, Greg KH wrote: > On Tue, Sep 23, 2014 at 10:57:09AM +0800, Hui Zhu wrote: >> The cause of this issue is when free memroy size is low and a lot of task is >> trying to shrink the memory, the task that is killed by lowmemkiller cannot get >> CPU to exit itself. >> >> Fix this issue with change the scheduling policy to SCHED_FIFO if a task's flag >> is TIF_MEMDIE in lowmemkiller. >> >> Signed-off-by: Hui Zhu >> --- >> drivers/staging/android/lowmemorykiller.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c >> index b545d3d..ca1ffac 100644 >> --- a/drivers/staging/android/lowmemorykiller.c >> +++ b/drivers/staging/android/lowmemorykiller.c >> @@ -129,6 +129,10 @@ static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc) >> >> if (test_tsk_thread_flag(p, TIF_MEMDIE) && >> time_before_eq(jiffies, lowmem_deathpending_timeout)) { >> + struct sched_param param = { .sched_priority = 1 }; >> + >> + if (p->policy == SCHED_NORMAL) >> + sched_setscheduler(p, SCHED_FIFO, ¶m); > > This seems really specific to a specific scheduler pattern now. Isn't > there some other way to resolve this? I tried to let the task that call lowmemkiller sleep some time when it try to kill same task. But it doesn't work. I think the issue is that the free memroy size is too low to make more and more tasks come to call lowmemkiller. Thanks, Hui > > thanks, > > greg k-h > {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I