From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758449AbZEEWUy (ORCPT ); Tue, 5 May 2009 18:20:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755670AbZEEWUo (ORCPT ); Tue, 5 May 2009 18:20:44 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:52201 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754419AbZEEWUn (ORCPT ); Tue, 5 May 2009 18:20:43 -0400 From: "Rafael J. Wysocki" To: David Rientjes Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Wed, 6 May 2009 00:19:35 +0200 User-Agent: KMail/1.11.2 (Linux/2.6.30-rc4-rjw; KDE/4.2.2; x86_64; ; ) Cc: Andrew Morton , Wu Fengguang , linux-pm@lists.linux-foundation.org, pavel@ucw.cz, torvalds@linux-foundation.org, jens.axboe@oracle.com, alan-jenkins@tuffmail.co.uk, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org References: <200905050023.38064.rjw@sisk.pl> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200905060019.36542.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 05 May 2009, David Rientjes wrote: > On Tue, 5 May 2009, Rafael J. Wysocki wrote: > > > Index: linux-2.6/kernel/power/process.c > > =================================================================== > > --- linux-2.6.orig/kernel/power/process.c > > +++ linux-2.6/kernel/power/process.c > > @@ -19,6 +19,8 @@ > > */ > > #define TIMEOUT (20 * HZ) > > > > +static bool tasks_frozen; > > + > > static inline int freezeable(struct task_struct * p) > > { > > if ((p == current) || > > @@ -120,6 +122,10 @@ int freeze_processes(void) > > Exit: > > BUG_ON(in_atomic()); > > printk("\n"); > > + > > + if (!error) > > + tasks_frozen = true; > > + > > return error; > > } > > > > @@ -145,6 +151,8 @@ static void thaw_tasks(bool nosig_only) > > > > void thaw_processes(void) > > { > > + tasks_frozen = false; > > + > > printk("Restarting tasks ... "); > > thaw_tasks(true); > > thaw_tasks(false); > > @@ -152,3 +160,7 @@ void thaw_processes(void) > > printk("done.\n"); > > } > > > > +bool processes_are_frozen(void) > > +{ > > + return tasks_frozen; > > +} > > Index: linux-2.6/include/linux/freezer.h > > =================================================================== > > --- linux-2.6.orig/include/linux/freezer.h > > +++ linux-2.6/include/linux/freezer.h > > @@ -50,6 +50,7 @@ extern int thaw_process(struct task_stru > > extern void refrigerator(void); > > extern int freeze_processes(void); > > extern void thaw_processes(void); > > +extern bool processes_are_frozen(void); > > > > static inline int try_to_freeze(void) > > { > > @@ -170,6 +171,7 @@ static inline int thaw_process(struct ta > > static inline void refrigerator(void) {} > > static inline int freeze_processes(void) { BUG(); return 0; } > > static inline void thaw_processes(void) {} > > +static inline bool processes_are_frozen(void) { return false; } > > > > static inline int try_to_freeze(void) { return 0; } > > > > Index: linux-2.6/mm/page_alloc.c > > =================================================================== > > --- linux-2.6.orig/mm/page_alloc.c > > +++ linux-2.6/mm/page_alloc.c > > @@ -46,6 +46,7 @@ > > #include > > #include > > #include > > +#include > > > > #include > > #include > > @@ -1599,7 +1600,8 @@ nofail_alloc: > > zonelist, high_zoneidx, alloc_flags); > > if (page) > > goto got_pg; > > - } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) { > > + } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY) > > + && !processes_are_frozen()) { > > if (!try_set_zone_oom(zonelist, gfp_mask)) { > > schedule_timeout_uninterruptible(1); > > goto restart; > > Cool, that looks like the semantics of __GFP_NO_OOM_KILL without requiring > a new gfp flag. Thanks. Well, you're welcome. BTW, I think that Andrew was actually right when he asked if I checked whether the existing __GFP_NORETRY would work as-is for __GFP_FS set and __GFP_NORETRY unset. Namely, in that case we never reach the code before nopage: that checks __GFP_NORETRY, do we? So I think we shouldn't modify the 'else if' condition above and check for !processes_are_frozen() at the beginning of the block below. Thanks, Rafael From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Wed, 6 May 2009 00:19:35 +0200 Message-ID: <200905060019.36542.rjw@sisk.pl> References: <200905050023.38064.rjw@sisk.pl> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: David Rientjes Cc: Andrew Morton , Wu Fengguang , linux-pm-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, pavel-+ZI9xUNit7I@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, alan-jenkins-cCz0Lq7MMjm9FHfhHBbuYA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Tuesday 05 May 2009, David Rientjes wrote: > On Tue, 5 May 2009, Rafael J. Wysocki wrote: > > > Index: linux-2.6/kernel/power/process.c > > =================================================================== > > --- linux-2.6.orig/kernel/power/process.c > > +++ linux-2.6/kernel/power/process.c > > @@ -19,6 +19,8 @@ > > */ > > #define TIMEOUT (20 * HZ) > > > > +static bool tasks_frozen; > > + > > static inline int freezeable(struct task_struct * p) > > { > > if ((p == current) || > > @@ -120,6 +122,10 @@ int freeze_processes(void) > > Exit: > > BUG_ON(in_atomic()); > > printk("\n"); > > + > > + if (!error) > > + tasks_frozen = true; > > + > > return error; > > } > > > > @@ -145,6 +151,8 @@ static void thaw_tasks(bool nosig_only) > > > > void thaw_processes(void) > > { > > + tasks_frozen = false; > > + > > printk("Restarting tasks ... "); > > thaw_tasks(true); > > thaw_tasks(false); > > @@ -152,3 +160,7 @@ void thaw_processes(void) > > printk("done.\n"); > > } > > > > +bool processes_are_frozen(void) > > +{ > > + return tasks_frozen; > > +} > > Index: linux-2.6/include/linux/freezer.h > > =================================================================== > > --- linux-2.6.orig/include/linux/freezer.h > > +++ linux-2.6/include/linux/freezer.h > > @@ -50,6 +50,7 @@ extern int thaw_process(struct task_stru > > extern void refrigerator(void); > > extern int freeze_processes(void); > > extern void thaw_processes(void); > > +extern bool processes_are_frozen(void); > > > > static inline int try_to_freeze(void) > > { > > @@ -170,6 +171,7 @@ static inline int thaw_process(struct ta > > static inline void refrigerator(void) {} > > static inline int freeze_processes(void) { BUG(); return 0; } > > static inline void thaw_processes(void) {} > > +static inline bool processes_are_frozen(void) { return false; } > > > > static inline int try_to_freeze(void) { return 0; } > > > > Index: linux-2.6/mm/page_alloc.c > > =================================================================== > > --- linux-2.6.orig/mm/page_alloc.c > > +++ linux-2.6/mm/page_alloc.c > > @@ -46,6 +46,7 @@ > > #include > > #include > > #include > > +#include > > > > #include > > #include > > @@ -1599,7 +1600,8 @@ nofail_alloc: > > zonelist, high_zoneidx, alloc_flags); > > if (page) > > goto got_pg; > > - } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) { > > + } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY) > > + && !processes_are_frozen()) { > > if (!try_set_zone_oom(zonelist, gfp_mask)) { > > schedule_timeout_uninterruptible(1); > > goto restart; > > Cool, that looks like the semantics of __GFP_NO_OOM_KILL without requiring > a new gfp flag. Thanks. Well, you're welcome. BTW, I think that Andrew was actually right when he asked if I checked whether the existing __GFP_NORETRY would work as-is for __GFP_FS set and __GFP_NORETRY unset. Namely, in that case we never reach the code before nopage: that checks __GFP_NORETRY, do we? So I think we shouldn't modify the 'else if' condition above and check for !processes_are_frozen() at the beginning of the block below. Thanks, Rafael