From: Minchan Kim <minchan.kim@gmail.com>
To: Mel Gorman <mgorman@suse.de>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Pádraig Brady" <P@draigBrady.com>,
"James Bottomley" <James.Bottomley@HansenPartnership.com>,
"Colin King" <colin.king@canonical.com>,
"Andrew Lutomirski" <luto@mit.edu>,
"Rik van Riel" <riel@redhat.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
linux-mm <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/4] mm: vmscan: Only read new_classzone_idx from pgdat when reclaiming successfully
Date: Wed, 20 Jul 2011 01:09:03 +0900 [thread overview]
Message-ID: <20110719160903.GA2978@barrios-desktop> (raw)
In-Reply-To: <1308926697-22475-5-git-send-email-mgorman@suse.de>
Hi Mel,
Too late review.
At that time, I had no time to look into this patch.
On Fri, Jun 24, 2011 at 03:44:57PM +0100, Mel Gorman wrote:
> During allocator-intensive workloads, kswapd will be woken frequently
> causing free memory to oscillate between the high and min watermark.
> This is expected behaviour. Unfortunately, if the highest zone is
> small, a problem occurs.
>
> When balance_pgdat() returns, it may be at a lower classzone_idx than
> it started because the highest zone was unreclaimable. Before checking
Yes.
> if it should go to sleep though, it checks pgdat->classzone_idx which
> when there is no other activity will be MAX_NR_ZONES-1. It interprets
Yes.
> this as it has been woken up while reclaiming, skips scheduling and
Hmm. I can't understand this part.
If balance_pgdat returns lower classzone and there is no other activity,
new_classzone_idx is always MAX_NR_ZONES - 1 so that classzone_idx would be less than
new_classzone_idx. It means it doesn't skip scheduling.
Do I miss something?
--
Kinds regards,
Minchan Kim
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next prev parent reply other threads:[~2011-07-19 16:09 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-24 14:44 [PATCH 0/4] Stop kswapd consuming 100% CPU when highest zone is small Mel Gorman
2011-06-24 14:44 ` [PATCH 1/4] mm: vmscan: Correct check for kswapd sleeping in sleeping_prematurely Mel Gorman
2011-06-25 21:33 ` Rik van Riel
2011-06-27 6:10 ` Minchan Kim
2011-06-28 21:49 ` Andrew Morton
2011-06-29 10:57 ` Pádraig Brady
2011-06-30 9:39 ` Mel Gorman
2011-06-30 2:23 ` KOSAKI Motohiro
2011-06-24 14:44 ` [PATCH 2/4] mm: vmscan: Do not apply pressure to slab if we are not applying pressure to zone Mel Gorman
2011-06-25 21:40 ` Rik van Riel
2011-06-28 23:38 ` Minchan Kim
2011-06-30 2:37 ` KOSAKI Motohiro
2011-06-24 14:44 ` [PATCH 3/4] mm: vmscan: Evaluate the watermarks against the correct classzone Mel Gorman
2011-06-25 21:42 ` Rik van Riel
2011-06-27 6:53 ` Minchan Kim
2011-06-28 12:52 ` Mel Gorman
2011-06-28 23:23 ` Minchan Kim
2011-06-28 23:23 ` Minchan Kim
2011-06-24 14:44 ` [PATCH 4/4] mm: vmscan: Only read new_classzone_idx from pgdat when reclaiming successfully Mel Gorman
2011-06-25 23:17 ` Rik van Riel
2011-06-30 9:05 ` KOSAKI Motohiro
2011-06-30 10:19 ` Mel Gorman
2011-07-19 16:09 ` Minchan Kim [this message]
2011-07-20 10:48 ` Mel Gorman
2011-07-21 15:30 ` Minchan Kim
2011-07-21 16:07 ` Mel Gorman
2011-07-21 16:36 ` Minchan Kim
2011-07-21 17:01 ` Mel Gorman
2011-07-22 0:21 ` Minchan Kim
2011-07-22 7:42 ` Mel Gorman
2011-06-25 14:23 ` [PATCH 0/4] Stop kswapd consuming 100% CPU when highest zone is small Andrew Lutomirski
2011-07-21 15:37 ` Minchan Kim
2011-07-21 16:09 ` Mel Gorman
2011-07-21 16:24 ` Minchan Kim
2011-07-21 16:36 ` Andrew Lutomirski
2011-07-21 16:42 ` Minchan Kim
2011-07-21 16:58 ` Andrew Lutomirski
2011-07-22 0:30 ` Minchan Kim
2011-07-22 13:21 ` Andrew Lutomirski
-- strict thread matches above, loose matches on Subject: below --
2011-06-24 13:43 Mel Gorman
2011-06-24 13:43 ` [PATCH 4/4] mm: vmscan: Only read new_classzone_idx from pgdat when reclaiming successfully Mel Gorman
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