Re: [PATCH] slab/mempolicy: always use local policy from interruptcontext v3
From: Pekka Enberg
Date: Fri Jun 01 2012 - 02:41:48 EST
On Thu, May 31, 2012 at 11:45 PM, David Rientjes <rientjes@xxxxxxxxxx> wrote:
> On Wed, 30 May 2012, Andi Kleen wrote:
>
>> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
>> index cfb6c86..b65eb06 100644
>> --- a/mm/mempolicy.c
>> +++ b/mm/mempolicy.c
>> @@ -1586,9 +1586,11 @@ static unsigned interleave_nodes(struct mempolicy *policy)
>> * task can change it's policy. The system default policy requires no
>> * such protection.
>> */
>> -unsigned slab_node(struct mempolicy *policy)
>> +unsigned slab_node(void)
>> {
>> - if (!policy || policy->flags & MPOL_F_LOCAL)
>> + struct mempolicy *policy = current->mempolicy;
>> +
>> + if (in_interrupt() || !policy || policy->flags & MPOL_F_LOCAL)
>> return numa_node_id();
>>
>> switch (policy->mode) {
>
> I think the version proposed by David Mackey is more clear, it makes it
> obvious that we don't want to dereference current in interrupt context
> whereas that relies on short-circuiting your conditional in your approach.
I like it better also. Christoph, Andi?
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