| Date | Wed, 16 Jun 2010 16:43:09 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 08/12] vmscan: Setup pagevec as late as possible in shrink_inactive_list() |
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On Mon, 14 Jun 2010 12:17:49 +0100 Mel Gorman <mel@csn.ul.ie> wrote:
> shrink_inactive_list() sets up a pagevec to release unfreeable pages. It > uses significant amounts of stack doing this. This patch splits > shrink_inactive_list() to take the stack usage out of the main path so > that callers to writepage() do not contain an unused pagevec on the > stack.
You can get the entire pagevec off the stack - just make it a static-to-shrink_inactive_list() pagevec-per-cpu.
Locking just requires pinning to a CPU. We could trivially co-opt shrink_inactive_list()'s spin_lock_irq() for that, but pagevec_release() can be relatively expensive so it'd be sad to move that inside spin_lock_irq(). It'd be better to slap a get_cpu()/put_cpu() around the whole thing.
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