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Commit 9363b9f2 authored by Balbir Singh's avatar Balbir Singh Committed by Linus Torvalds
Browse files

memrlimit: cgroup mm owner callback changes to add task info 



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: default avatarBalbir 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: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1648993f

include/linux/cgroup.h

+2 −1
Original line number Diff line number Diff line
@@ -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;

kernel/cgroup.c

+3 −1
Original line number Diff line number Diff line
@@ -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);

		}

	}

}

kernel/exit.c

+4 −5
Original line number Diff line number Diff line
@@ -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 */