Re: [RFC PATCH 0/4]: affinity-on-next-touch

From: Brice Goglin
Date: Mon Jun 22 2009 - 13:06:05 EST

Lee Schermerhorn wrote:
> The primary difference should be at unmap time, right? In the fault
> path, I only update the pte of the faulting task. That's why I require
> the [anon] pages to be in the swap cache [or something similar]. I
> don't want to be fixing up other tasks' page tables in the context of
> the faulting task's fault handler. If, later, another task touches the
> page, it will take a minor fault and find the [possibly migrated] page
> in the cache. Hmmm, I guess all tasks WILL incur the minor fault if
> they touch the page after the unmap. That could be part of the
> difference if you compare on the same kernel version.


> Try booting with cgroup_disable=memory on the command line, if you have
> the memory resource controller configured in. See what that does to
> your measurements.

It doesn't seem to help. I'll try to bisect and find where the
performance dropped.

> ??? I would expect low level page copying to be highly optimized per
> arch, and also fairly stable.

I just did a quick copy_page benchmark and didn't see any performance
difference between 2.6.27 and mmotm.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at