From: Vlastimil Babka <vbabka@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>,
Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Minchan Kim <minchan@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/4] mm, page_alloc: fix dirtyable highmem calculation
Date: Thu, 14 Jul 2016 17:22:25 +0200 [thread overview]
Message-ID: <1e5938cd-0e03-6cb9-4d5f-fee94fc1479e@suse.cz> (raw)
In-Reply-To: <1468404004-5085-4-git-send-email-mgorman@techsingularity.net>
On 07/13/2016 12:00 PM, Mel Gorman wrote:
> From: Minchan Kim <minchan@kernel.org>
>
> Note from Mel: This may optionally be considered a fix to the mmotm patch
> mm-page_alloc-consider-dirtyable-memory-in-terms-of-nodes.patch
> but if so, please preserve credit for Minchan.
>
> When I tested vmscale in mmtest in 32bit, I found the benchmark was slow
> down 0.5 times.
>
> base node
> 1 global-1
> User 12.98 16.04
> System 147.61 166.42
> Elapsed 26.48 38.08
>
> With vmstat, I found IO wait avg is much increased compared to base.
>
> The reason was highmem_dirtyable_memory accumulates free pages and
> highmem_file_pages from HIGHMEM to MOVABLE zones which was wrong. With
> that, dirth_thresh in throtlle_vm_write is always 0 so that it calls
> congestion_wait frequently if writeback starts.
>
> With this patch, it is much recovered.
>
> base node fi
> 1 global-1 fix
> User 12.98 16.04 13.78
> System 147.61 166.42 143.92
> Elapsed 26.48 38.08 29.64
>
> Signed-off-by: Minchan Kim <minchan@kernel.org>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Just some nitpicks:
> ---
> mm/page-writeback.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 0bca2376bd42..7b41d1290783 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -307,27 +307,31 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
> {
> #ifdef CONFIG_HIGHMEM
> int node;
> - unsigned long x = 0;
> + unsigned long x;
> int i;
> - unsigned long dirtyable = atomic_read(&highmem_file_pages);
> + unsigned long dirtyable = 0;
This wasn't necessary?
>
> for_each_node_state(node, N_HIGH_MEMORY) {
> for (i = ZONE_NORMAL + 1; i < MAX_NR_ZONES; i++) {
> struct zone *z;
> + unsigned long nr_pages;
>
> if (!is_highmem_idx(i))
> continue;
>
> z = &NODE_DATA(node)->node_zones[i];
> - dirtyable += zone_page_state(z, NR_FREE_PAGES);
> + if (!populated_zone(z))
> + continue;
>
> + nr_pages = zone_page_state(z, NR_FREE_PAGES);
> /* watch for underflows */
> - dirtyable -= min(dirtyable, high_wmark_pages(z));
> -
> - x += dirtyable;
> + nr_pages -= min(nr_pages, high_wmark_pages(z));
> + dirtyable += nr_pages;
> }
> }
>
> + x = dirtyable + atomic_read(&highmem_file_pages);
And then this addition wouldn't be necessary. BTW I think we could also
ditch the "x" variable and just use the "dirtyable" for the rest of the
function.
> +
> /*
> * Unreclaimable memory (kernel memory or anonymous memory
> * without swap) can bring down the dirtyable pages below
>
--
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/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-07-14 15:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-13 10:00 [PATCH 0/4] Follow-up fixes to node-lru series v1 Mel Gorman
2016-07-13 10:00 ` [PATCH 1/4] mm, vmscan: Have kswapd reclaim from all zones if reclaiming and buffer_heads_over_limit -fix Mel Gorman
2016-07-13 13:10 ` Johannes Weiner
2016-07-14 1:22 ` Minchan Kim
2016-07-13 10:00 ` [PATCH 2/4] mm: vmstat: account per-zone stalls and pages skipped during reclaim -fix Mel Gorman
2016-07-13 13:10 ` Johannes Weiner
2016-07-14 14:45 ` Vlastimil Babka
2016-07-13 10:00 ` [PATCH 3/4] mm, page_alloc: fix dirtyable highmem calculation Mel Gorman
2016-07-13 13:15 ` Johannes Weiner
2016-07-14 15:22 ` Vlastimil Babka [this message]
2016-07-13 10:00 ` [PATCH 4/4] mm: move most file-based accounting to the node -fix Mel Gorman
2016-07-13 13:16 ` Johannes Weiner
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=1e5938cd-0e03-6cb9-4d5f-fee94fc1479e@suse.cz \
--to=vbabka@suse.cz \
--cc=akpm@linux-foundation.org \
--cc=hannes@cmpxchg.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=minchan@kernel.org \
/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).