From: Michal Hocko <mhocko@suse.cz>
To: Shaohua Li <shaohua.li@intel.com>
Cc: Andrew Morton <akpm@google.com>, mel <mel@csn.ul.ie>,
Rik van Riel <riel@redhat.com>, linux-mm <linux-mm@kvack.org>
Subject: Re: [patch 2/2]vmscan: correctly detect GFP_ATOMIC allocation failure
Date: Tue, 27 Sep 2011 13:28:10 +0200 [thread overview]
Message-ID: <20110927112810.GA3897@tiehlicka.suse.cz> (raw)
In-Reply-To: <1317108187.29510.201.camel@sli10-conroe>
On Tue 27-09-11 15:23:07, Shaohua Li wrote:
> has_under_min_watermark_zone is used to detect if there is GFP_ATOMIC allocation
> failure risk. For a high end_zone, if any zone below or equal to it has min
> matermark ok, we have no risk. But current logic is any zone has min watermark
> not ok, then we have risk. This is wrong to me.
This, however, means that we skip congestion_wait more often as ZONE_DMA
tend to be mostly balanced, right? This would mean that kswapd could hog
CPU more.
Does this fix any particular problem you are seeing?
>
> Signed-off-by: Shaohua Li <shaohua.li@intel.com>
> ---
> mm/vmscan.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> Index: linux/mm/vmscan.c
> ===================================================================
> --- linux.orig/mm/vmscan.c 2011-09-27 15:09:29.000000000 +0800
> +++ linux/mm/vmscan.c 2011-09-27 15:14:45.000000000 +0800
> @@ -2463,7 +2463,7 @@ loop_again:
>
> for (priority = DEF_PRIORITY; priority >= 0; priority--) {
> unsigned long lru_pages = 0;
> - int has_under_min_watermark_zone = 0;
> + int has_under_min_watermark_zone = 1;
>
> /* The swap token gets in the way of swapout... */
> if (!priority)
> @@ -2594,9 +2594,10 @@ loop_again:
> * means that we have a GFP_ATOMIC allocation
> * failure risk. Hurry up!
> */
> - if (!zone_watermark_ok_safe(zone, order,
> + if (has_under_min_watermark_zone &&
> + zone_watermark_ok_safe(zone, order,
> min_wmark_pages(zone), end_zone, 0))
> - has_under_min_watermark_zone = 1;
> + has_under_min_watermark_zone = 0;
> } else {
> /*
> * If a zone reaches its high watermark,
>
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2011-09-27 11:28 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-27 7:23 [patch 2/2]vmscan: correctly detect GFP_ATOMIC allocation failure Shaohua Li
2011-09-27 11:28 ` Michal Hocko [this message]
2011-09-28 0:48 ` Shaohua Li
2011-09-28 9:27 ` Michal Hocko
2011-10-08 3:14 ` Shaohua Li
2011-10-08 3:19 ` David Rientjes
2011-10-08 3:35 ` Shaohua Li
2011-10-08 5:56 ` [patch v2]vmscan: " Shaohua Li
2011-10-08 10:25 ` Minchan Kim
2011-10-09 5:53 ` Shaohua Li
2011-10-09 8:01 ` Minchan Kim
2011-10-09 8:17 ` Shaohua Li
2011-10-09 15:10 ` Minchan Kim
2011-10-10 7:28 ` Shaohua Li
2011-10-10 15:42 ` Minchan Kim
2011-10-11 5:30 ` Shaohua Li
2011-10-11 6:54 ` Minchan Kim
2011-10-12 2:48 ` Shaohua Li
2011-10-12 7:59 ` Minchan Kim
2011-10-18 2:13 ` [patch v3]vmscan: " Shaohua Li
2011-10-27 22:50 ` Minchan Kim
2011-10-28 5:15 ` Shaohua Li
2011-11-07 5:15 ` Shaohua Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110927112810.GA3897@tiehlicka.suse.cz \
--to=mhocko@suse.cz \
--cc=akpm@google.com \
--cc=linux-mm@kvack.org \
--cc=mel@csn.ul.ie \
--cc=riel@redhat.com \
--cc=shaohua.li@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).