Re: [PATCH] mm/readahead.c: update the LRU positions of in-corepages, too

[Wu Fengguang]

On Mon, Jan 25, 2010 at 03:36:35PM -0700, Chris Frost wrote:
> I changed Wu's patch to add a PageLRU() guard that I believe is required
> and optimized zone lock acquisition to only unlock and lock at zone changes.
> This optimization seems to provide a 10-20% system time improvement for
> some of my GIMP benchmarks and no improvement for other benchmarks.

> +			del_page_from_lru_list(zone, page, lru);
> +			add_page_to_lru_list(zone, page, lru);
> +		}
> +		put_page(page);

Hmm. put_page() inside lru_lock can deadlock. So you need to further
optimize the code to do pagevec_lookup() and pagevec_release() plus
cond_resched().

Thanks,
Fengguang
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