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From: Mel Gorman <mgorman@suse.de>
To: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: linux-mm@kvack.org
Subject: Re: [PATCH RFC] mm: lru milestones, timestamps and ages
Date: Fri, 10 May 2013 11:28:09 +0100	[thread overview]
Message-ID: <20130510102809.GA31738@suse.de> (raw)
In-Reply-To: <20130430110214.22179.26139.stgit@zurg>

On Tue, Apr 30, 2013 at 03:02:14PM +0400, Konstantin Khlebnikov wrote:
> +static inline bool
> +is_lru_milestone(struct lruvec *lruvec, struct list_head *list)
> +{
> +	return unlikely(list >= &lruvec->milestones[0][0].lru &&
> +			list <  &lruvec->milestones[NR_EVICTABLE_LRU_LISTS]
> +						   [NR_LRU_MILESTONES].lru);
> +}
> +

Not reviewing properly yet, just taking a quick look out of interest but
this check may be delicate.  32-bit x86 machines start the kernel direct
mapping at 0xC0000000 so milestones[0][0].lru will have some value betewen
0xC0000000 and 0xFFFFFFFF. HZ=250 on my distro config so after 0xC0000000
jiffies or a bit over 149 days of uptime, it looks like there will be a
window where LRU entries look like milestones. If I'm right, that is
bound to cause problems.

-- 
Mel Gorman
SUSE Labs

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  parent reply	other threads:[~2013-05-10 10:28 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-30 11:02 [PATCH RFC] mm: lru milestones, timestamps and ages Konstantin Khlebnikov
2013-05-03 14:07 ` Zlatko Calusic
2013-05-04 11:53   ` Konstantin Khlebnikov
2013-05-04 13:01     ` Konstantin Khlebnikov
2013-05-04 21:36       ` Zlatko Calusic
2013-05-06 19:08       ` Johannes Weiner
2013-05-04 13:32     ` Zlatko Calusic
2013-05-10 10:28 ` Mel Gorman [this message]
2013-05-10 14:12   ` Konstantin Khlebnikov

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