Messages in this thread | | | Date | Mon, 28 Feb 2011 14:54:02 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH 2/2] mm: compaction: Minimise the time IRQs are disabled while isolating pages for migration |
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On Mon, 28 Feb 2011 06:48:18 +0100 Andrea Arcangeli <aarcange@redhat.com> wrote:
> On Mon, Feb 28, 2011 at 11:17:46AM +0900, KAMEZAWA Hiroyuki wrote: > > BTW, I forget why we always take zone->lru_lock with IRQ disabled.... > > To decrease lock contention in SMP to deliver overall better > performance (not sure how much it helps though). It was supposed to be > hold for a very short time (PAGEVEC_SIZE) to avoid giving irq latency > problems. >
memory hotplug uses MIGRATE_ISOLATED migrate types for scanning pfn range without lru_lock. I wonder whether we can make use of it (the function which memory hotplug may need rework for the compaction but migrate_type can be used, I think).
Hmm. -Kame
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