Re: [rfc] [patch] mm: zone_reclaim fix for pseudo file systems

Ravikiran G Thirumalai
2007-07-31T07:15:02Z

On Mon, Jul 30, 2007 at 10:00:15PM -0700, Christoph Lameter wrote:
>On Mon, 30 Jul 2007, Andrew Morton wrote:
>
>> On Mon, 30 Jul 2007 19:36:04 -0700 (PDT) Christoph Lameter <clameter@sgi.com> wrote:
>>
>> > On Mon, 30 Jul 2007, Andrew Morton wrote:
>> >
>> > > That makes sense, but any fix we do here won't fix things for regular
>> > > reclaim.
>> >
>> > Standard reclaim has the same issues. It uselessly keeps
>> > scanning the unreclaimable file backed pages.
>>
>> Well it shouldn't. That's what all_unreclaimable is for. And it does
>> work. Or used to, five years ago. Stuff like this has a habit of breaking
>> because we don't have a test suite.
>
>The current VM has never been able to handle it since we have never had
>logic to remove unreclaimable pages from the LRU.
>
>Lets bring up the patchsets for the handling of unreclaimable pages up
>again (mlocked and anonymous/no swap) again and make sure that it also
>addresses the issue issue here so that we have a comprehensive solution.
>
>I am going over my old patchsets anyways. Kiran: Did you have a look at
>the patches Nick and I did earlier this year for mlocked pages?

Yes. I guess it is good to move unrelclaimable pages off LRU. But we still
need to not get into reclaim when we don't have pages to reclaim. That is,
fix the arithmetic here. No?