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SubjectRe: RFC: dirty_ratio back to 40%
Did this patch get merged somewhere?

On Thu, May 20, 2010 at 07:20:42AM -0400, Larry Woodman wrote:
> We've seen multiple performance regressions linked to the lower(20%)
> dirty_ratio. When performing enough IO to overwhelm the background
> flush daemons the percent of dirty pagecache memory quickly climbs
> to the new/lower dirty_ratio value of 20%. At that point all
> writing processes are forced to stop and write dirty pagecache pages
> back to disk. This causes performance regressions in several
> benchmarks as well as causing
> a noticeable overall sluggishness. We all know that the dirty_ratio is
> an integrity vs performance trade-off but the file system journaling
> will cover any devastating effects in the event of a system crash.
>
> Increasing the dirty_ratio to 40% will regain the performance loss seen
> in several benchmarks. Whats everyone think about this???
>
>
>
>
>
> ------------------------------------------------------------------------
>
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index ef27e73..645a462 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -78,7 +78,7 @@ int vm_highmem_is_dirtyable;
> /*
> * The generator of dirty data starts writeback at this percentage
> */
> -int vm_dirty_ratio = 20;
> +int vm_dirty_ratio = 40;
>
> /*
> * vm_dirty_bytes starts at 0 (disabled) so that it is a function of
>
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---end quoted text---


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