Re: 2.4.7-ac4 disk thrashing

[Dieter Nützel]

Am Mittwoch, 8. August 2001 17:41 schrieb Daniel Phillips:
> On Wednesday 08 August 2001 12:57, Alan Cox wrote:
> > > Could it be that the ReiserFS cleanups in ac4 do harm?
> > > http://marc.theaimsgroup.com/?l=3Dreiserfs&m=3D99683332027428&w=3D2
> >
> > I suspect the use once patch is the more relevant one.
>
> Two things to check:
>
>   - Linus found a bug in balance_dirty_state yesterday.  Is the
>     fix applied?

No, I'll try.

>   - The original use-once patch tends to leave a referenced pages
>     on the inactive_dirty queue longer, not in itself a problem,
>     but can expose other problems.  The previously posted patch
>     below fixes that, is it applied?
>
> To apply (with use-once already applied):

Yes, it was with -ac9.

But it wasn't much different from ac6/7/8 without it. All nearly "equally 
bad". The disk steps like mad compared against 2.4.7-ac1 and ac-3. I can 
"hear" it and the whole system "feels" slow.
2.4.7-ac1 + transaction-tracking-2 (Chris) + use-once-pages 
(Daniel) + 2.4.7-unlink-truncate-rename-rmdir.dif (Nikita) is the best Linux 
I've ever run.

I did several (~10 times) dbench-1.1 (should I retry with dbench-1.2?) and 
all gave nearly same results.

ac-1, ac3 + fixes			GREAT
ac5, ac6, ac7, ac8, ac9 + fixes	BAD

Thanks,
	Dieter

>   cd /usr/src/your.2.4.7.source.tree
>   patch -p0 <this.patch
>
> --- ../2.4.7.clean/mm/filemap.c	Sat Aug  4 14:27:16 2001
> +++ ./mm/filemap.c	Sat Aug  4 23:41:00 2001
> @@ -979,9 +979,13 @@
>
>  static inline void check_used_once (struct page *page)
>  {
> -	if (!page->age) {
> -		page->age = PAGE_AGE_START;
> -		ClearPageReferenced(page);
> +	if (!PageActive(page)) {
> +		if (page->age)
> +			activate_page(page);
> +		else {
> +			page->age = PAGE_AGE_START;
> +			ClearPageReferenced(page);
> +		}
>  	}
>  }