Re: [PATCH 4/4] writeback: Reporting dirty thresholds in /proc/vmstat

From: KOSAKI Motohiro
Date: Sun Aug 22 2010 - 06:28:18 EST


> > The kernel already exposes the user desired thresholds in /proc/sys/vm
> > with dirty_background_ratio and background_ratio. But the kernel may
> > alter the number requested without giving the user any indication that
> > is the case.
> >
> > Knowing the actual ratios the kernel is honoring can help app developers
> > understand how their buffered IO will be sent to the disk.
> >
> > $ grep threshold /proc/vmstat
> > nr_dirty_threshold 409111
> > nr_dirty_background_threshold 818223
> >
> > Signed-off-by: Michael Rubin <mrubin@xxxxxxxxxx>
>
> Looks good to me.
> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>

sorry, this is mistake. Wu pointed out this patch is unnecessary.


Wu wrote:
> I realized that the dirty thresholds has already been exported here:
>
> $ grep Thresh /debug/bdi/8:0/stats
> BdiDirtyThresh: 381000 kB
> DirtyThresh: 1719076 kB
> BackgroundThresh: 859536 kB
>
> So why not use that interface directly?



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