Re: [PATCH 1/5] Swap Migration V5: LRU operations

[Christoph Lameter]

On Tue, 15 Nov 2005, Andrew Morton wrote:

> But lru_add_drain_per_cpu() will be called from interrupt context: the IPI
> handler.

Ahh.. thought you meant the lru_add_drain run on the local processor.
 
> I'm asking whether it is safe for the IPI handler to reenable interupts on
> all architectures.  It might be so, but I don't recall ever having seen it
> discussed, nor have I seen code which does it.

smp_call_function is also used by the slab allocator to drain the 
pages. All the spinlocks in there and those of the page allocator (called 
for freeing pages) use spin_lock_irqsave. Why is this not used for 
lru_add_drain() and friends?

Maybe we need to start a new thread so that others see it?

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