From: Mel Gorman <mgorman@suse.de>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.cz>,
Hugh Dickins <hughd@google.com>,
Satoru Moriya <satoru.moriya@hds.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 3/7] mm: vmscan: clarify how swappiness, highest priority, memcg interact
Date: Tue, 18 Dec 2012 10:04:50 +0000 [thread overview]
Message-ID: <20121218100449.GK9887@suse.de> (raw)
In-Reply-To: <1355767957-4913-4-git-send-email-hannes@cmpxchg.org>
On Mon, Dec 17, 2012 at 01:12:33PM -0500, Johannes Weiner wrote:
> A swappiness of 0 has a slightly different meaning for global reclaim
> (may swap if file cache really low) and memory cgroup reclaim (never
> swap, ever).
>
> In addition, global reclaim at highest priority will scan all LRU
> lists equal to their size and ignore other balancing heuristics.
> UNLESS swappiness forbids swapping, then the lists are balanced based
> on recent reclaim effectiveness. UNLESS file cache is running low,
> then anonymous pages are force-scanned.
>
> This (total mess of a) behaviour is implicit and not obvious from the
> way the code is organized. At least make it apparent in the code flow
> and document the conditions. It will be it easier to come up with
> sane semantics later.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
--
Mel Gorman
SUSE Labs
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WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@suse.de>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.cz>,
Hugh Dickins <hughd@google.com>,
Satoru Moriya <satoru.moriya@hds.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 3/7] mm: vmscan: clarify how swappiness, highest priority, memcg interact
Date: Tue, 18 Dec 2012 10:04:50 +0000 [thread overview]
Message-ID: <20121218100449.GK9887@suse.de> (raw)
In-Reply-To: <1355767957-4913-4-git-send-email-hannes@cmpxchg.org>
On Mon, Dec 17, 2012 at 01:12:33PM -0500, Johannes Weiner wrote:
> A swappiness of 0 has a slightly different meaning for global reclaim
> (may swap if file cache really low) and memory cgroup reclaim (never
> swap, ever).
>
> In addition, global reclaim at highest priority will scan all LRU
> lists equal to their size and ignore other balancing heuristics.
> UNLESS swappiness forbids swapping, then the lists are balanced based
> on recent reclaim effectiveness. UNLESS file cache is running low,
> then anonymous pages are force-scanned.
>
> This (total mess of a) behaviour is implicit and not obvious from the
> way the code is organized. At least make it apparent in the code flow
> and document the conditions. It will be it easier to come up with
> sane semantics later.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2012-12-18 10:04 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-17 18:12 [patch 0/8] page reclaim bits v2 Johannes Weiner
2012-12-17 18:12 ` Johannes Weiner
2012-12-17 18:12 ` [patch 1/7] mm: memcg: only evict file pages when we have plenty Johannes Weiner
2012-12-17 18:12 ` Johannes Weiner
2012-12-17 18:15 ` Rik van Riel
2012-12-17 18:15 ` Rik van Riel
2012-12-18 9:56 ` Mel Gorman
2012-12-18 9:56 ` Mel Gorman
2012-12-17 18:12 ` [patch 2/7] mm: vmscan: save work scanning (almost) empty LRU lists Johannes Weiner
2012-12-17 18:12 ` Johannes Weiner
2012-12-19 23:59 ` Andrew Morton
2012-12-19 23:59 ` Andrew Morton
2012-12-20 13:55 ` Michal Hocko
2012-12-20 13:55 ` Michal Hocko
2012-12-21 3:02 ` Johannes Weiner
2012-12-21 3:02 ` Johannes Weiner
2012-12-17 18:12 ` [patch 3/7] mm: vmscan: clarify how swappiness, highest priority, memcg interact Johannes Weiner
2012-12-17 18:12 ` Johannes Weiner
2012-12-17 18:16 ` Rik van Riel
2012-12-17 18:16 ` Rik van Riel
2012-12-17 19:37 ` Satoru Moriya
2012-12-17 19:37 ` Satoru Moriya
2012-12-17 20:05 ` Michal Hocko
2012-12-17 20:05 ` Michal Hocko
2012-12-18 10:04 ` Mel Gorman [this message]
2012-12-18 10:04 ` Mel Gorman
2012-12-18 15:16 ` Satoru Moriya
2012-12-18 15:16 ` Satoru Moriya
2012-12-17 18:12 ` [patch 4/7] mm: vmscan: improve comment on low-page cache handling Johannes Weiner
2012-12-17 18:12 ` Johannes Weiner
2012-12-17 18:12 ` [patch 5/7] mm: vmscan: clean up get_scan_count() Johannes Weiner
2012-12-17 18:12 ` Johannes Weiner
2012-12-20 0:08 ` Andrew Morton
2012-12-20 0:08 ` Andrew Morton
2012-12-21 2:49 ` Johannes Weiner
2012-12-21 2:49 ` Johannes Weiner
2012-12-17 18:12 ` [patch 6/7] mm: vmscan: compaction works against zones, not lruvecs Johannes Weiner
2012-12-17 18:12 ` Johannes Weiner
2012-12-17 18:12 ` [patch 7/7] mm: reduce rmap overhead for ex-KSM page copies created on swap faults Johannes Weiner
2012-12-17 18:12 ` Johannes Weiner
2012-12-17 22:42 ` Hugh Dickins
2012-12-17 22:42 ` Hugh Dickins
2012-12-19 7:01 ` Simon Jeons
2012-12-19 7:01 ` Simon Jeons
2012-12-19 17:58 ` Johannes Weiner
2012-12-19 17:58 ` Johannes Weiner
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