From: Andrew Morton <akpm@linux-foundation.org>
To: Jamie Liu <jamieliu@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Mel Gorman <mgorman@suse.de>, Greg Thelen <gthelen@google.com>,
Hugh Dickins <hughd@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: vmscan: count only dirty pages as congested
Date: Wed, 15 Oct 2014 13:05:44 -0700 [thread overview]
Message-ID: <20141015130544.380aca0acfcb1413459520b0@linux-foundation.org> (raw)
In-Reply-To: <1413403115-1551-1-git-send-email-jamieliu@google.com>
On Wed, 15 Oct 2014 12:58:35 -0700 Jamie Liu <jamieliu@google.com> wrote:
> shrink_page_list() counts all pages with a mapping, including clean
> pages, toward nr_congested if they're on a write-congested BDI.
> shrink_inactive_list() then sets ZONE_CONGESTED if nr_dirty ==
> nr_congested. Fix this apples-to-oranges comparison by only counting
> pages for nr_congested if they count for nr_dirty.
>
> ...
>
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -875,7 +875,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> * end of the LRU a second time.
> */
> mapping = page_mapping(page);
> - if ((mapping && bdi_write_congested(mapping->backing_dev_info)) ||
> + if (((dirty || writeback) && mapping &&
> + bdi_write_congested(mapping->backing_dev_info)) ||
> (writeback && PageReclaim(page)))
> nr_congested++;
What are the observed runtime effects of this change?
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next prev parent reply other threads:[~2014-10-15 20:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-15 19:58 Jamie Liu
2014-10-15 20:05 ` Andrew Morton [this message]
2014-10-15 23:07 ` Jamie Liu
2014-10-15 23:16 ` Andrew Morton
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