Re: [PATCH 5/5] slub: Only IPI CPUs that have per cpu obj to flush

[Pekka Enberg]

On Mon, 26 Sep 2011, Gilad Ben-Yossef wrote:
> Peter basically already answered better then I could :-)
>
> All I have to add is an example -
>
> flush_all() is called for each kmem_cahce_destroy(). So every cache
> being destroyed dynamically ends up sending an IPI to each CPU in the
> system, regardless if the cache has ever been used there.
>
> For example, if you close the Infinband ipath driver char device file,
> the close file ops calls kmem_cache_destroy().So, if I understand
> correctly, running some infiniband config tool on one a single CPU
> dedicated to system tasks might interrupt the rest of the 127 CPUs I
> dedicated to some CPU intensive task. This is the scenario I'm
> tryingto avoid.
>
> I suspect there is a good chance that every line in the output of "git
> grep kmem_cache_destroy linux/ | grep '\->'" has a similar scenario
> (there are 42 of them).
>
> I hope this sheds some light on the motive of the work.

Sure.

If you write down such information in the changelog for future patches, I 
don't need to waste your time asking for an explanation. ;-)

			Pekka
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/