Messages in this thread | | | Date | Tue, 1 Mar 2011 00:07:12 +0100 | From | Andrea Arcangeli <> | Subject | Re: [PATCH 2/2] mm: compaction: Minimise the time IRQs are disabled while isolating pages for migration |
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On Tue, Mar 01, 2011 at 08:01:31AM +0900, Minchan Kim wrote: > I am not sure it's good if we release the lock whenever lru->lock was contended > unconditionally? There are many kinds of lru_lock operations(add to lru, > del from lru, isolation, reclaim, activation, deactivation and so on).
This is mostly to mirror cond_resched_lock (which actually uses spin_needbreak but it's ok to have it also when preempt is off). I doubt it makes a big difference but I tried to mirror cond_resched_lock.
> Do we really need to release the lock whenever all such operations were contened? > I think what we need is just spin_is_contended_irqcontext. > Otherwise, please write down the comment for justifying for it.
What is spin_is_contended_irqcontext?
> This patch is for reducing for irq latency but do we have to check signal > in irq hold time?
I think it's good idea to check the signal in case the loop is very long and this is run in direct compaction context.
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