Messages in this thread | | | Date | Thu, 21 Jul 2011 18:35:40 +0900 | From | KOSAKI Motohiro <> | Subject | Re: [PATCH 3/3] mm: page allocator: Reconsider zones for allocation after direct reclaim |
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Hi
>> So, I think we don't need to care zonelist, just kswapd turn off >> their own node. > > I don't understand what you mean by this.
This was the answer of following your comments.
> Instead, couldn't we turn zlc->fullzones off from kswapd? > > > > Which zonelist should it clear (there are two)
I mean, buddy list is belong to zone, not zonelist. therefore, kswapd don't need to look up zonelist.
So, I'd suggest either following way, - use direct reclaim path, but only clear a zlc bit of zones in reclaimed zonelist, not all. or - use kswapd and only clear a zlc bit at kswap exiting balance_pgdat
I'm prefer to add a branch to slowpath (ie reclaim path) rather than fast path.
>> And, just curious, If we will have a proper zlc clear point, why >> do we need to keep HZ timeout? > > Yes because we are not guaranteed to call direct reclaim either. Memory > could be freed by a process exiting and I'd rather not add cost to > the free path to find and clear all zonelists referencing the zone the > page being freed belongs to.
Ok, it's good trade-off. I agree we need to keep HZ timeout.
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