From: Dave Chinner <david@fromorbit.com>
To: Glauber Costa <glommer@parallels.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, xfs@oss.sgi.com
Subject: Re: [PATCH 09/19] list_lru: per-node list infrastructure
Date: Fri, 21 Dec 2012 12:54:10 +1100 [thread overview]
Message-ID: <20121221015410.GB15182@dastard> (raw)
In-Reply-To: <50D2F4B6.9040108@parallels.com>
On Thu, Dec 20, 2012 at 03:21:26PM +0400, Glauber Costa wrote:
> On 11/28/2012 03:14 AM, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > Now that we have an LRU list API, we can start to enhance the
> > implementation. This splits the single LRU list into per-node lists
> > and locks to enhance scalability. Items are placed on lists
> > according to the node the memory belongs to. To make scanning the
> > lists efficient, also track whether the per-node lists have entries
> > in them in a active nodemask.
> >
>
> I think it is safe to assume that these functions could benefit from
> having more metadata available for them when they run.
>
> Let's say for instance that a hypothetical person, for some unknown
> reasons, comes with the idea of replicating those lists transparently
> per memcg.
>
> In this case, it is very useful to know which memcg drives the current
> call. In general, the struct shrink_control already contains a lot of
> data that we use to drive the process. Wouldn't it make sense to also
> pass shrink_control as data to those lists as well?
I considered it, but:
> The only drawback of this, is that it would tie it to the shrinking
> process.
and that's exactly what I didn't want to do. Yes, the shrinkers need
to walk the list, but they will not be/are not the only reason we
need to walk lists and isolate items....
> I am not sure if this is a concern, but it if is, maybe we
> could replace things like :
>
> +static long
> +list_lru_walk_node(
> + struct list_lru *lru,
> + int nid,
> + list_lru_walk_cb isolate,
> + void *cb_arg,
> + long *nr_to_walk)
> +{
>
> with
>
> +static long
> +list_lru_walk_node(
> + struct list_lru *lru,
> + struct something_like_shrink_control_not_shrink_control *a)
> +{
>
> This way we can augment the data available for the interface, for
> instance, passing the memcg context, without going patching all the callers.
Yes, that is also something I considered. I just never got around to
doing it as I wasn't sure whether the walking interface woul dbe
acceptible in the first place. If we do use the list walk interface
list this, then we shoul definitely encapsulate all the parameters
in a struct something_like_shrink_control_not_shrink_control. :)
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2012-12-21 1:54 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-27 23:14 [RFC, PATCH 00/19] Numa aware LRU lists and shrinkers Dave Chinner
2012-11-27 23:14 ` [PATCH 01/19] dcache: convert dentry_stat.nr_unused to per-cpu counters Dave Chinner
2012-11-27 23:14 ` [PATCH 02/19] dentry: move to per-sb LRU locks Dave Chinner
2012-11-27 23:14 ` [PATCH 03/19] dcache: remove dentries from LRU before putting on dispose list Dave Chinner
2012-11-27 23:14 ` [PATCH 04/19] mm: new shrinker API Dave Chinner
2012-11-27 23:14 ` [PATCH 05/19] shrinker: convert superblock shrinkers to new API Dave Chinner
2012-12-20 11:06 ` Glauber Costa
2012-12-21 1:46 ` Dave Chinner
2012-12-21 10:17 ` Glauber Costa
2012-11-27 23:14 ` [PATCH 06/19] list: add a new LRU list type Dave Chinner
2012-11-28 16:10 ` Christoph Hellwig
2012-11-27 23:14 ` [PATCH 07/19] inode: convert inode lru list to generic lru list code Dave Chinner
2012-11-27 23:14 ` [PATCH 08/19] dcache: convert to use new lru list infrastructure Dave Chinner
2012-11-27 23:14 ` [PATCH 09/19] list_lru: per-node " Dave Chinner
2012-12-20 11:21 ` Glauber Costa
2012-12-21 1:54 ` Dave Chinner [this message]
2013-01-16 19:21 ` Glauber Costa
2013-01-16 22:55 ` Dave Chinner
2013-01-17 0:35 ` Glauber Costa
2013-01-17 4:22 ` Dave Chinner
2013-01-17 18:21 ` Glauber Costa
2013-01-18 0:10 ` Dave Chinner
2013-01-18 0:14 ` Glauber Costa
2013-01-18 8:11 ` Dave Chinner
2013-01-18 19:10 ` Glauber Costa
2013-01-19 0:10 ` Dave Chinner
2013-01-19 0:13 ` Glauber Costa
2013-01-18 0:51 ` Glauber Costa
2013-01-18 8:08 ` Dave Chinner
2013-01-18 19:01 ` Glauber Costa
2012-11-27 23:14 ` [PATCH 10/19] shrinker: add node awareness Dave Chinner
2012-11-27 23:14 ` [PATCH 11/19] fs: convert inode and dentry shrinking to be node aware Dave Chinner
2012-11-27 23:14 ` [PATCH 12/19] xfs: convert buftarg LRU to generic code Dave Chinner
2012-11-27 23:14 ` [PATCH 13/19] xfs: Node aware direct inode reclaim Dave Chinner
2012-11-27 23:14 ` [PATCH 14/19] xfs: use generic AG walk for background " Dave Chinner
2012-11-27 23:14 ` [PATCH 15/19] xfs: convert dquot cache lru to list_lru Dave Chinner
2012-11-28 16:17 ` Christoph Hellwig
2012-11-27 23:14 ` [PATCH 16/19] fs: convert fs shrinkers to new scan/count API Dave Chinner
2012-11-27 23:14 ` [PATCH 17/19] drivers: convert shrinkers to new count/scan API Dave Chinner
2012-11-28 1:13 ` Chris Wilson
2012-11-28 3:17 ` Dave Chinner
2012-11-28 8:21 ` Glauber Costa
2012-11-28 21:28 ` Dave Chinner
2012-11-29 10:29 ` Glauber Costa
2012-11-29 22:02 ` Dave Chinner
2013-06-07 13:37 ` Konrad Rzeszutek Wilk
2012-11-27 23:14 ` [PATCH 18/19] shrinker: convert remaining shrinkers to " Dave Chinner
2012-11-27 23:14 ` [PATCH 19/19] shrinker: Kill old ->shrink API Dave Chinner
2012-11-29 19:02 ` [RFC, PATCH 00/19] Numa aware LRU lists and shrinkers Andi Kleen
2012-11-29 22:09 ` Dave Chinner
2012-12-20 11:45 ` Glauber Costa
2012-12-21 2:50 ` Dave Chinner
2012-12-21 10:41 ` Glauber Costa
2013-01-21 16:08 ` Glauber Costa
2013-01-21 23:21 ` Dave Chinner
2013-01-23 14:36 ` Glauber Costa
2013-01-23 23:46 ` Dave Chinner
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