Re: [PATCH] mmtom: Prevent shrinking of active anon lru list in caseof no swap space V2

From: Rik van Riel
Date: Thu May 14 2009 - 08:58:56 EST


Minchan Kim wrote:

Now shrink_active_list is called several places.
But if we don't have a swap space, we can't reclaim anon pages.

If swap space has run out, get_scan_ratio() will return
0 for the anon scan ratio, meaning we do not scan the
anon lists.

So, we don't need deactivating anon pages in anon lru list.

If we are close to running out of swap space, with
swapins freeing up swap space on a regular basis,
I believe we do want to do aging on the active
pages, just so we can pick a decent page to swap
out next time swap space becomes available.

+static int can_reclaim_anon(struct zone *zone, struct scan_control *sc)
+{
+ return (inactive_anon_is_low(zone, sc) && nr_swap_pages <= 0);
+}
+

This function name is misleading, because when we do have
swap space available but inactive_anon_is_low is false,
we still want to reclaim inactive anon pages!

What problem did you encounter that you think this patch
solves?

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