Hi Rik,
This has nice effects here. With 320M memory starting a tob backup would put
about 120M in the buffer cache. With this applied it peaks at about 60M - the
system also remains more interactive.
If buffer_mem.borrow_percent is not used anywhere else suggest we reduce the
default percentage a bit more and see if things get even better.
Thoughts
Ed Tomlinson
On August 9, 2001 04:55 pm, Rik van Riel wrote:
> On Thu, 9 Aug 2001, marc heckmann wrote:
> > While 2.4.8-pre7 definitely fixes the "dd if=/dev/zero
> > of=bigfile bs=1000k count=bignumber" case. The "dd if=/dev/hda
> > of=/dev/null" is still quite broken for me.
>
> OK, there is no obvious way to do do drop-behind on
> buffer cache pages, but I think we can use a quick
> hack to make the system behave well under the presence
> of large amounts of buffer cache pages.
>
> What we could do is, in refill_inactive_scan(), just
> moving buffer cache pages to the inactive list regardless
> of page aging when there are too many buffercache pages
> around in the system.
>
> Does the patch below help you ?
>
> regards,
>
> Rik
> --
> IA64: a worthy successor to the i860.
>
> http://www.surriel.com/
> http://www.conectiva.com/ http://distro.conectiva.com/
>
>
> --- linux-2.4.7-ac7/mm/vmscan.c.buffer Thu Aug 9 17:54:24 2001
> +++ linux-2.4.7-ac7/mm/vmscan.c Thu Aug 9 17:55:09 2001
> @@ -708,6 +708,8 @@
> * This function will scan a portion of the active list to find
> * unused pages, those pages will then be moved to the inactive list.
> */
> +#define too_many_buffers (atomic_read(&buffermem_pages) > \
> + (num_physpages * buffer_mem.borrow_percent / 100))
> int refill_inactive_scan(zone_t *zone, unsigned int priority, int target)
> {
> struct list_head * page_lru;
> @@ -770,6 +772,18 @@
> page_active = 1;
> }
> }
> +
> + /*
> + * If the amount of buffer cache pages is too
> + * high we just move every buffer cache page we
> + * find to the inactive list. Eventually they'll
> + * be reclaimed there...
> + */
> + if (page->buffers && !page->mapping && too_many_buffers) {
> + deactivate_page_nolock(page);
> + page_active = 0;
> + }
> +
> /*
> * If the page is still on the active list, move it
> * to the other end of the list. Otherwise we exit if
>
> --
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This archive was generated by hypermail 2b29 : Wed Aug 15 2001 - 21:00:32 EST