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| author | Lee Schermerhorn <lee.schermerhorn@hp.com> | 2008-04-28 02:13:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-28 08:58:24 -0700 |
| commit | ae4d8c16aa22775f5731677abb8a82f03cec877e (patch) | |
| tree | 2d34c6fd334b51cc5f3265cd4ec26db758639b5c | |
| parent | f4e53d910b7dde2685b177f1e7c3e3e0b4a42f7b (diff) | |
| download | linux-ae4d8c16aa22775f5731677abb8a82f03cec877e.tar.bz2 | |
mempolicy: fixup Fallback for Default Shmem Policy
get_vma_policy() is not handling fallback to task policy correctly when the
get_policy() vm_op returns NULL. The NULL overwrites the 'pol' variable that
was holding the fallback task mempolicy. So, it was falling back directly to
system default policy.
Fix get_vma_policy() to use only non-NULL policy returned from the vma
get_policy op.
shm_get_policy() was falling back to current task's mempolicy if the "backing
file system" [tmpfs vs hugetlbfs] does not support the get_policy vm_op and
the vma policy is null. This is incorrect for show_numa_maps() which is
likely querying the numa_maps of some task other than current. Remove this
fallback.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | ipc/shm.c | 3 | ||||
| -rw-r--r-- | mm/mempolicy.c | 7 |
2 files changed, 6 insertions, 4 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index cc63fae02f06..8d1b2c468cc4 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -274,8 +274,7 @@ static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, else if (vma->vm_policy) { pol = vma->vm_policy; mpol_get(pol); /* get_vma_policy() expects this */ - } else - pol = current->mempolicy; + } return pol; } #endif diff --git a/mm/mempolicy.c b/mm/mempolicy.c index c6c61ea6bb8c..8924aaf4665c 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1262,7 +1262,7 @@ asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len, * @task != current]. It is the caller's responsibility to * free the reference in these cases. */ -static struct mempolicy * get_vma_policy(struct task_struct *task, +static struct mempolicy *get_vma_policy(struct task_struct *task, struct vm_area_struct *vma, unsigned long addr) { struct mempolicy *pol = task->mempolicy; @@ -1270,7 +1270,10 @@ static struct mempolicy * get_vma_policy(struct task_struct *task, if (vma) { if (vma->vm_ops && vma->vm_ops->get_policy) { - pol = vma->vm_ops->get_policy(vma, addr); + struct mempolicy *vpol = vma->vm_ops->get_policy(vma, + addr); + if (vpol) + pol = vpol; shared_pol = 1; /* if pol non-NULL, add ref below */ } else if (vma->vm_policy && vma->vm_policy->policy != MPOL_DEFAULT) |