Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6b6482bb authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

mempolicy: remove the "task" arg of vma_policy_mof() and simplify it 



1. vma_policy_mof(task) is simply not safe unless task == current,
   it can race with do_exit()->mpol_put(). Remove this arg and update
   its single caller.

2. vma can not be NULL, remove this check and simplify the code.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8d90274b

include/linux/mempolicy.h

+1 −1
Original line number Diff line number Diff line
@@ -136,7 +136,7 @@ struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, 


struct mempolicy *get_vma_policy(struct task_struct *tsk,

		struct vm_area_struct *vma, unsigned long addr);

bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma);

bool vma_policy_mof(struct vm_area_struct *vma);



extern void numa_default_policy(void);

extern void numa_policy_init(void);

kernel/sched/fair.c

+1 −1
Original line number Diff line number Diff line
@@ -1946,7 +1946,7 @@ void task_numa_work(struct callback_head *work) 
		vma = mm->mmap;

	}

	for (; vma; vma = vma->vm_next) {

		if (!vma_migratable(vma) || !vma_policy_mof(p, vma))

		if (!vma_migratable(vma) || !vma_policy_mof(vma))

			continue;



		/*

mm/mempolicy.c

+11 −14
Original line number Diff line number Diff line
@@ -1646,11 +1646,10 @@ struct mempolicy *get_vma_policy(struct task_struct *task, 
	return pol;

}



bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma)

bool vma_policy_mof(struct vm_area_struct *vma)

{

	struct mempolicy *pol = NULL;

	struct mempolicy *pol;



	if (vma) {

	if (vma->vm_ops && vma->vm_ops->get_policy) {

		bool ret = false;
@@ -1663,10 +1662,8 @@ bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma) 
	}



	pol = vma->vm_policy;

	}



	if (!pol)

		pol = get_task_policy(task);

		pol = get_task_policy(current);



	return pol->flags & MPOL_F_MOF;

}