Re: Linux 2.4.1-ac7

Marcelo Tosatti (marcelo@conectiva.com.br)
Sat, 10 Feb 2001 07:46:14 -0200 (BRST)


On Sat, 10 Feb 2001, Mike Galbraith wrote:

> Hi Rik,
>
> This change makes my box swap madly under load. It appears to be
> keeping more cache around than is really needed, and therefore
> having to resort to swap instead. The result is MUCH more I/O than
> previous kernels while doing the same exact job.
>
> My test load is make -jN bzImage. Previous kernels kept cache at
> an average of ~20ish mb at a job level N at which level I had nearly
> zero measurable throughput loss compared to single task compile.
>
> >>From that, I surmise that the cachable component of this job must
> fit in that roughly 20ish mb of space. (for otherwise, I would be
> suffering throughput loss). With this vm change, cache is nearly
> three times as large as usual. Where 30 tasks will run with only
> modest throughput loss in ac5, ac8 throughput tapers off rapidly
> at half of that.

Swapped out pages were not being counted in the flushing limitation.

Could you try the following patch?

Thanks

--- linux.orig/mm/vmscan.c Sat Feb 10 08:26:17 2001
+++ linux/mm/vmscan.c Sat Feb 10 09:34:20 2001
@@ -515,6 +515,7 @@

writepage(page);
flushed_pages++;
+ max_launder--;
page_cache_release(page);

/* And re-start the thing.. */

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