Re: [RFC] Scalable statistics counters using kmalloc_percpu

[Andrew Morton]

Ravikiran G Thirumalai wrote:
> 
> ...
> 
> > General comment:  we need to clean up the kernel_stat stuff.  We
> > cannot just make it per-cpu because it is 32k in size already.  I
> > would suggest that we should break out the disk accounting and
> > make the rest of kernel_stat per CPU.
> >
> > That would be a great application of your interface, and a good
> > way to get your interface merged ;)  Is that something which you
> > have time to do?
> 
> Sure,... anything to get these interfaces merged :)

Well Rusty's point about just using the percpu API seemed
reasonable - that's basically equivalent to statically defining
the data.  In what situation is dynamic allocation needed?

Well, in modules for one.  Unless we work out a way to make the
percpu API work with storage which is defined within modules.

> Are you looking at something on the lines as the diff below?

Looks nice.

> What about /proc/stat ? Is it a good idea to have separate /proc files
> for disk stats and cpu usage stats? (It'll be good for statctrs that way,
> applications monitoring disk_stats only don't cause statctr_reads on
> cpu_usage stats then)

Stick with the existing format, I'd say.   Numerous applications
would break otherwise.

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