From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751125AbaDVNYA (ORCPT ); Tue, 22 Apr 2014 09:24:00 -0400 Received: from cantor2.suse.de ([195.135.220.15]:39377 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750773AbaDVNX6 (ORCPT ); Tue, 22 Apr 2014 09:23:58 -0400 Date: Tue, 22 Apr 2014 15:23:55 +0200 From: Michal Hocko To: Oleg Nesterov Cc: Andrew Morton , Peter Chiang , KAMEZAWA Hiroyuki , Balbir Singh , Johannes Weiner , "ccross@android.com" , "lizefan@huawei.com" , "tj@kernel.org" , "pavel@ucw.cz" , "ebiederm@xmission.com" , "guillaume@morinfr.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 0/1] memcg: kill start_kernel()->mm_init_owner(init_mm) Message-ID: <20140422132355.GO29311@dhcp22.suse.cz> References: <1397617379-26895-1-git-send-email-pchiang@nvidia.com> <80341664FB79C2419999599F48F738410227327881@HKMAIL01.nvidia.com> <80341664FB79C2419999599F48F738410227327888@HKMAIL01.nvidia.com> <20140416135741.GA9407@redhat.com> <80341664FB79C2419999599F48F7384102273279C3@HKMAIL01.nvidia.com> <20140418162359.GA4398@redhat.com> <20140418172631.GA13323@redhat.com> <20140418182444.GB22235@dhcp22.suse.cz> <20140418184441.GA26046@redhat.com> <20140418191259.GA7413@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140418191259.GA7413@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 18-04-14 21:12:59, Oleg Nesterov wrote: > On 04/18, Oleg Nesterov wrote: > > > > OTOH, mm->owner is used by mm/memcontrol.c, so perhaps the prefix is fine? > > > > I do not even understand why do we have CONFIG_MM_OWNER, perhaps it should > > die? > > Seriously what do you think about the patch below? Afaics CONFIG_MM_OWNER > is pointless. Yes, I do not see any reason for a separate config when it has a single user which cannot work without it. So feel free to add my Acked-by: Michal Hocko to the patch with your s-o-b and a simple changelog explaining there the config option didn't have any user outside of MEMCG which cannot work without it. > And I just noticed start_kernel()->mm_init_owner(). It looks simply wrong > even if this is harmless, or I missed something? > > Could you review 1/1 as well? > > Oleg. > --- > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 8967e20..de16272 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -406,7 +406,7 @@ struct mm_struct { > spinlock_t ioctx_lock; > struct kioctx_table __rcu *ioctx_table; > #endif > -#ifdef CONFIG_MM_OWNER > +#ifdef CONFIG_MEMCG > /* > * "owner" points to a task that is regarded as the canonical > * user/owner of this mm. All of the following must be true in > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 82fe3da..570a325 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -2947,7 +2947,7 @@ static inline void inc_syscw(struct task_struct *tsk) > #define TASK_SIZE_OF(tsk) TASK_SIZE > #endif > > -#ifdef CONFIG_MM_OWNER > +#ifdef CONFIG_MEMCG > extern void mm_update_next_owner(struct mm_struct *mm); > extern void mm_init_owner(struct mm_struct *mm, struct task_struct *p); > #else > @@ -2958,7 +2958,7 @@ static inline void mm_update_next_owner(struct mm_struct *mm) > static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p) > { > } > -#endif /* CONFIG_MM_OWNER */ > +#endif /* CONFIG_MEMCG */ > > static inline unsigned long task_rlimit(const struct task_struct *tsk, > unsigned int limit) > diff --git a/init/Kconfig b/init/Kconfig > index 765018c..143119e 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -933,7 +933,6 @@ config RESOURCE_COUNTERS > config MEMCG > bool "Memory Resource Controller for Control Groups" > depends on RESOURCE_COUNTERS > - select MM_OWNER > select EVENTFD > help > Provides a memory resource controller that manages both anonymous > @@ -951,9 +950,6 @@ config MEMCG > disable memory resource controller and you can avoid overheads. > (and lose benefits of memory resource controller) > > - This config option also selects MM_OWNER config option, which > - could in turn add some fork/exit overhead. > - > config MEMCG_SWAP > bool "Memory Resource Controller Swap Extension" > depends on MEMCG && SWAP > @@ -1173,9 +1169,6 @@ config SCHED_AUTOGROUP > desktop applications. Task group autogeneration is currently based > upon task session. > > -config MM_OWNER > - bool > - > config SYSFS_DEPRECATED > bool "Enable deprecated sysfs features to support old userspace tools" > depends on SYSFS > diff --git a/kernel/exit.c b/kernel/exit.c > index 429659c..e5c4668 100644 > --- a/kernel/exit.c > +++ b/kernel/exit.c > @@ -313,7 +313,7 @@ kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) > } > } > > -#ifdef CONFIG_MM_OWNER > +#ifdef CONFIG_MEMCG > /* > * A task is exiting. If it owned this mm, find a new owner for the mm. > */ > @@ -399,7 +399,7 @@ assign_new_owner: > task_unlock(c); > put_task_struct(c); > } > -#endif /* CONFIG_MM_OWNER */ > +#endif /* CONFIG_MEMCG */ > > /* > * Turn us into a lazy TLB process if we > diff --git a/kernel/fork.c b/kernel/fork.c > index 54a8d26..ed75cf5 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -1099,12 +1099,12 @@ static void rt_mutex_init_task(struct task_struct *p) > #endif > } > > -#ifdef CONFIG_MM_OWNER > +#ifdef CONFIG_MEMCG > void mm_init_owner(struct mm_struct *mm, struct task_struct *p) > { > mm->owner = p; > } > -#endif /* CONFIG_MM_OWNER */ > +#endif /* CONFIG_MEMCG */ > > /* > * Initialize POSIX timer handling for a single task. > -- Michal Hocko SUSE Labs