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author | Oleg Nesterov <oleg@redhat.com> | 2014-10-09 15:27:48 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-09 22:25:56 -0400 |
commit | 6b6482bbf64ef6f6dbc8b52f7a7cf88a0498bd51 (patch) | |
tree | 026e6f1a304c6a9f4da4462427e21fa3178fddfa | |
parent | 8d90274b3b118c9babeefb1302947f33a1364fb5 (diff) | |
download | op-kernel-dev-6b6482bbf64ef6f6dbc8b52f7a7cf88a0498bd51.zip op-kernel-dev-6b6482bbf64ef6f6dbc8b52f7a7cf88a0498bd51.tar.gz |
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: Oleg 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | include/linux/mempolicy.h | 2 | ||||
-rw-r--r-- | kernel/sched/fair.c | 2 | ||||
-rw-r--r-- | mm/mempolicy.c | 25 |
3 files changed, 13 insertions, 16 deletions
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index f230a97..5e4bfce 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -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); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index bfa3c86..82088b2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -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; /* diff --git a/mm/mempolicy.c b/mm/mempolicy.c index b86b08e..ad27bbc 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1646,27 +1646,24 @@ 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; - - if (vma) { - if (vma->vm_ops && vma->vm_ops->get_policy) { - bool ret = false; + struct mempolicy *pol; - pol = vma->vm_ops->get_policy(vma, vma->vm_start); - if (pol && (pol->flags & MPOL_F_MOF)) - ret = true; - mpol_cond_put(pol); + if (vma->vm_ops && vma->vm_ops->get_policy) { + bool ret = false; - return ret; - } + pol = vma->vm_ops->get_policy(vma, vma->vm_start); + if (pol && (pol->flags & MPOL_F_MOF)) + ret = true; + mpol_cond_put(pol); - pol = vma->vm_policy; + return ret; } + pol = vma->vm_policy; if (!pol) - pol = get_task_policy(task); + pol = get_task_policy(current); return pol->flags & MPOL_F_MOF; } |