Messages in this thread | | | Date | Wed, 17 Oct 2012 12:50:21 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [patch for-3.7] mm, mempolicy: fix printing stack contents in numa_maps |
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On Wed, 17 Oct 2012, KOSAKI Motohiro wrote:
> > I think this refcounting is better than using task_lock(). > > I don't think so. get_vma_policy() is used from fast path. In other > words, number of > atomic ops is sensible for allocation performance.
There are enhancements that we can make with refcounting: for instance, we may want to avoid doing it in the super-fast path when the policy is default_policy and then just do
if (mpol != &default_policy) mpol_put(mpol);
> Instead, I'd like > to use spinlock > for shared mempolicy instead of mutex. >
Um, this was just changed to a mutex last week in commit b22d127a39dd ("mempolicy: fix a race in shared_policy_replace()") so that sp_alloc() can be done with GFP_KERNEL, so I didn't consider reverting that behavior. Are you nacking that patch, which you acked, now?
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