On Sun, Jun 12, 2011 at 04:45:21PM +0200, Michal Hocko wrote:

On Tue 07-06-11 23:38:16, Minchan Kim wrote:

quoted

There are some places to isolate lru page and I believe
users of isolate_lru_page will be growing.
The purpose of them is each different so part of isolated pages
should put back to LRU, again.

The problem is when we put back the page into LRU,
we lose LRU ordering and the page is inserted at head of LRU list.
It makes unnecessary LRU churning so that vm can evict working set pages
rather than idle pages.

I guess that, although this is true, it doesn't fit in with this patch
very much because this patch doesn't fix this problem. It is a
preparation for for further work. I would expect this description with
the core patch that actlually handles this issue.

Okay.

quoted

This patch adds new modes when we isolate page in LRU so we don't isolate pages
if we can't handle it. It could reduce LRU churning.

This patch doesn't change old behavior. It's just used by next patches.

It doesn't because there is not user of those flags but maybe it would
be better to have those to see why it actually can reduce LRU
isolations.

Yes. Mel already pointed it out.
I will merge patches in next version.
And I have a idea to reduce lru_lock Mel mentiond
So maybe I will include it in next version, too.
But, now I have no time to revise it :(

-- 
Kind regards,
Minchan Kim

--
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>