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memrlimit: cgroup mm owner callback changes to add task info

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This patch adds an additional field to the mm_owner callbacks. This field
is required to get to the mm that changed. Hold mmap_sem in write mode
before calling the mm_owner_changed callback

[hugh@veritas.com: fix mmap_sem deadlock]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Balbir Singh 2008-10-15 22:01:05 -07:00 committed by Linus Torvalds
parent 1648993fb0
commit 9363b9f23c
3 changed files with 9 additions and 7 deletions
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3
include/linux/cgroup.h
View file

@ -326,7 +326,8 @@ struct cgroup_subsys {
*/
void (*mm_owner_changed)(struct cgroup_subsys *ss,
struct cgroup *old,
struct cgroup *new);
struct cgroup *new,
struct task_struct *p);
int subsys_id;
int active;
int disabled;

4
kernel/cgroup.c
View file

@ -2735,6 +2735,8 @@ void cgroup_fork_callbacks(struct task_struct *child)
* Called on every change to mm->owner. mm_init_owner() does not
* invoke this routine, since it assigns the mm->owner the first time
* and does not change it.
*
* The callbacks are invoked with mmap_sem held in read mode.
*/
void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
{
@ -2750,7 +2752,7 @@ void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
if (oldcgrp == newcgrp)
continue;
if (ss->mm_owner_changed)
ss->mm_owner_changed(ss, oldcgrp, newcgrp);
ss->mm_owner_changed(ss, oldcgrp, newcgrp, new);
}
}
}

9
kernel/exit.c
View file

@ -640,24 +640,23 @@ void mm_update_next_owner(struct mm_struct *mm)
assign_new_owner:
BUG_ON(c == p);
get_task_struct(c);
read_unlock(&tasklist_lock);
down_write(&mm->mmap_sem);
/*
* The task_lock protects c->mm from changing.
* We always want mm->owner->mm == mm
*/
task_lock(c);
/*
* Delay read_unlock() till we have the task_lock()
* to ensure that c does not slip away underneath us
*/
read_unlock(&tasklist_lock);
if (c->mm != mm) {
task_unlock(c);
up_write(&mm->mmap_sem);
put_task_struct(c);
goto retry;
}
cgroup_mm_owner_callbacks(mm->owner, c);
mm->owner = c;
task_unlock(c);
up_write(&mm->mmap_sem);
put_task_struct(c);
}
#endif /* CONFIG_MM_OWNER */