From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlastimil Babka Subject: Re: [PATCH 14/18] prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable Date: Fri, 11 Mar 2016 13:54:10 +0100 Message-ID: <56E2BFF2.1080208@suse.cz> References: <1456752417-9626-1-git-send-email-mhocko@kernel.org> <1456752417-9626-15-git-send-email-mhocko@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:43794 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752157AbcCKMyN (ORCPT ); Fri, 11 Mar 2016 07:54:13 -0500 In-Reply-To: <1456752417-9626-15-git-send-email-mhocko@kernel.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Michal Hocko , LKML Cc: Andrew Morton , linux-mm@kvack.org, Alex Deucher , Alex Thorlton , Andrea Arcangeli , Andy Lutomirski , Benjamin LaHaise , =?UTF-8?Q?Christian_K=c3=b6nig?= , Daniel Vetter , Dave Hansen , David Airlie , Davidlohr Bueso , David Rientjes , "H . Peter Anvin" , Hugh Dickins , Ingo Molnar , Johannes Weiner , "Kirill A . Shutemov" , Konstantin Khlebnikov , linux-arch@vger.kernel.org, Mel Gorman , Oleg Nesterov , Peter Zijlstra Pe On 02/29/2016 02:26 PM, Michal Hocko wrote: > From: Michal Hocko > > PR_SET_THP_DISABLE requires mmap_sem for write. If the waiting > task gets killed by the oom killer it would block oom_reaper from > asynchronous address space reclaim and reduce the chances of timely OOM > resolving. Wait for the lock in the killable mode and return with EINTR > if the task got killed while waiting. > > Cc: Alex Thorlton > Signed-off-by: Michal Hocko Acked-by: Vlastimil Babka > --- > kernel/sys.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/sys.c b/kernel/sys.c > index cf8ba545c7d3..89d5be418157 100644 > --- a/kernel/sys.c > +++ b/kernel/sys.c > @@ -2246,7 +2246,8 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, > case PR_SET_THP_DISABLE: > if (arg3 || arg4 || arg5) > return -EINVAL; > - down_write(&me->mm->mmap_sem); > + if (down_write_killable(&me->mm->mmap_sem)) > + return -EINTR; > if (arg2) > me->mm->def_flags |= VM_NOHUGEPAGE; > else > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:43794 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752157AbcCKMyN (ORCPT ); Fri, 11 Mar 2016 07:54:13 -0500 Subject: Re: [PATCH 14/18] prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable References: <1456752417-9626-1-git-send-email-mhocko@kernel.org> <1456752417-9626-15-git-send-email-mhocko@kernel.org> From: Vlastimil Babka Message-ID: <56E2BFF2.1080208@suse.cz> Date: Fri, 11 Mar 2016 13:54:10 +0100 MIME-Version: 1.0 In-Reply-To: <1456752417-9626-15-git-send-email-mhocko@kernel.org> Content-Type: text/plain; charset=iso-8859-2; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Michal Hocko , LKML Cc: Andrew Morton , linux-mm@kvack.org, Alex Deucher , Alex Thorlton , Andrea Arcangeli , Andy Lutomirski , Benjamin LaHaise , =?UTF-8?Q?Christian_K=c3=b6nig?= , Daniel Vetter , Dave Hansen , David Airlie , Davidlohr Bueso , David Rientjes , "H . Peter Anvin" , Hugh Dickins , Ingo Molnar , Johannes Weiner , "Kirill A . Shutemov" , Konstantin Khlebnikov , linux-arch@vger.kernel.org, Mel Gorman , Oleg Nesterov , Peter Zijlstra , Petr Cermak , Thomas Gleixner , Michal Hocko Message-ID: <20160311125410.-mhj1cVJZPER0-koy_2SH8wCzAL8VxVdbUjEbcVismI@z> On 02/29/2016 02:26 PM, Michal Hocko wrote: > From: Michal Hocko > > PR_SET_THP_DISABLE requires mmap_sem for write. If the waiting > task gets killed by the oom killer it would block oom_reaper from > asynchronous address space reclaim and reduce the chances of timely OOM > resolving. Wait for the lock in the killable mode and return with EINTR > if the task got killed while waiting. > > Cc: Alex Thorlton > Signed-off-by: Michal Hocko Acked-by: Vlastimil Babka > --- > kernel/sys.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/sys.c b/kernel/sys.c > index cf8ba545c7d3..89d5be418157 100644 > --- a/kernel/sys.c > +++ b/kernel/sys.c > @@ -2246,7 +2246,8 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, > case PR_SET_THP_DISABLE: > if (arg3 || arg4 || arg5) > return -EINVAL; > - down_write(&me->mm->mmap_sem); > + if (down_write_killable(&me->mm->mmap_sem)) > + return -EINTR; > if (arg2) > me->mm->def_flags |= VM_NOHUGEPAGE; > else >