On Wed, Jun 16, 2010 at 04:43:09PM -0700, Andrew Morton wrote: > On Mon, 14 Jun 2010 12:17:49 +0100 > Mel Gorman <mel@xxxxxxxxx> 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. > That idea has been floated as well. I didn't pursue it because Dave said that giving page reclaim a stack diet was never going to be the full solution so I didn't think the complexity was justified. I kept some of the stack reduction stuff because a) it was there and b) it would give kswapd extra headroom when calling writepage. > 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. > It'd be something interesting to try out when nothing else was happening but I'm not going to focus on it for the moment unless I think it will really help this stack overflow problem. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
