From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mgorman@suse.de>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: Reduce the amount of work done when updating min_free_kbytes
Date: Mon, 14 Nov 2011 15:21:00 -0800 [thread overview]
Message-ID: <20111114152100.1333a015.akpm@linux-foundation.org> (raw)
In-Reply-To: <20111111162119.GP3083@suse.de>
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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next prev parent reply other threads:[~2011-11-14 23:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-11 16:21 [PATCH] mm: Reduce the amount of work done when updating min_free_kbytes Mel Gorman
2011-11-14 23:21 ` Andrew Morton [this message]
2011-11-15 12:23 ` Mel Gorman
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