Re: [PATCH] vmscan: evict use-once pages first (v2)

[Andrew Morton]

On Thu, 30 Apr 2009 20:59:36 -0400
Rik van Riel <riel@xxxxxxxxxx> wrote:

> On Thu, 30 Apr 2009 17:45:36 -0700
> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> 
> > Were you able to tell whether altering /proc/sys/vm/swappiness
> > appropriately regulated the rate at which the mapped page count
> > decreased?
> 
> That should not make a difference at all for mapped file
> pages, after the change was merged that makes the VM ignores
> the referenced bit of mapped active file pages.
> 
> Ever since the split LRU code was merged, all that the
> swappiness controls is the aggressiveness of file vs
> anonymous LRU scanning.

Which would cause exactly the problem Elladan saw?

> Currently the kernel has no effective code to protect the 
> page cache working set from streaming IO.  Elladan's bug
> report shows that we do need some kind of protection...

Seems to me that reclaim should treat swapcache-backed mapped mages in
a similar fashion to file-backed mapped pages?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/