Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754127AbbG3KKf (ORCPT ); Thu, 30 Jul 2015 06:10:35 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:44664 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751177AbbG3KKd (ORCPT ); Thu, 30 Jul 2015 06:10:33 -0400 Date: Thu, 30 Jul 2015 13:09:37 +0300 From: Dan Carpenter To: "Wang, Biao" Cc: "gregkh@linuxfoundation.org" , "arve@android.com" , "riandrews@android.com" , "devel@driverdev.osuosl.org" , "Zhang, Di" , "Li, Fei" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] improve lmk to avoid deadlock issue Message-ID: <20150730100937.GM5180@mwanda> References: <09CB0B4607EB8F4DB7E0BE3B06BFBD051DA2DCAB@SHSMSX101.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09CB0B4607EB8F4DB7E0BE3B06BFBD051DA2DCAB@SHSMSX101.ccr.corp.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2630 Lines: 75 I'm not an android dev but this patch seems reasonable enough. There are some process issues though. 1) The subject should have a subsystem prefix: [PATCH] Staing: android: lowmemorykiller: improve lmk to avoid deadlock issue On Thu, Jul 30, 2015 at 06:49:53AM +0000, Wang, Biao wrote: > From: "wang, biao" > Date: Thu, 30 Jul 2015 14:14:44 +0800 > Subject: [PATCH] improve lmk to avoid deadlock issue 2) Don't put these lines in the patch. > > Consider the following case: > Task A trigger lmk with a lock held, while process B try to > get this lock, but unfortunately B is the very culprit Task lmk select to > kill. > So B will never be killed, and A will forever select B to kill and > such dead lock trigger softlock up issue. > This patch try to pick the next task to break this loop. > > Signed-off-by: wang, biao 3) Use capital letters for your name here. It should match your email address. > Signed-off-by: Zhang Di 4) Did Zhang write this patch? If so then add a From: tag at the top of the email to give authorship credit. Signed-off-by tags mean that the patch went through your hands somehow. Otherwise use the Reviewed-by, Reported-by, or Acked-by tag whichever is appropriate. > --- > drivers/staging/android/lowmemorykiller.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c > index feafa17..efabeb7 100644 > --- a/drivers/staging/android/lowmemorykiller.c > +++ b/drivers/staging/android/lowmemorykiller.c > @@ -127,11 +127,15 @@ static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc) > if (!p) > continue; > > - if (test_tsk_thread_flag(p, TIF_MEMDIE) && > - time_before_eq(jiffies, lowmem_deathpending_timeout)) { > - task_unlock(p); > - rcu_read_unlock(); > - return 0; > + if (test_tsk_thread_flag(p, TIF_MEMDIE)) { > + if (time_before_eq(jiffies, lowmem_deathpending_timeout)) { 5) This goes over the 80 character limit. Could you break it up like this: if (test_tsk_thread_flag(p, TIF_MEMDIE)) { if (time_before_eq(jiffies, lowmem_deathpending_timeout)) { task_unlock(p); Anyway, thank for this patch. Please fix these small process issues and resend. regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/