Messages in this thread | | | Date | Mon, 14 Nov 2011 15:21:00 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] mm: Reduce the amount of work done when updating min_free_kbytes |
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On Fri, 11 Nov 2011 16:21:19 +0000 Mel Gorman <mgorman@suse.de> wrote:
> When min_free_kbytes is updated, some pageblocks are marked MIGRATE_RESERVE. > Ordinarily, this work is unnoticable as it happens early in boot but on > large machines with 1TB of memory, this has been reported to delay > boot times, probably due to the NUMA distances involved. > > The bulk of the work is due to calling calling pageblock_is_reserved() > an unnecessary amount of times and accessing far more struct page > metadata than is necessary. This patch significantly reduces the > amount of work done by setup_zone_migrate_reserve() improving boot > times on 1TB machines. >
By how much? :)
(I mainly ask because I'm curious to know how long the kernel takes to boot on a 1TB machine...)
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