[lustre-devel] [PATCH 2/3] staging: lustre: lnet: Allocate MEs and small MDs in own kmem_caches

[Faccini, Bruno]

Le Jun 10, 2016 à 18:36, Greg Kroah-Hartman <gregkh at linuxfoundation.org<mailto:gregkh at linuxfoundation.org>> a écrit :


A: No.
Q: Should I include quotations after my reply?

http://daringfireball.net/2007/07/on_top

Thanks for the email formatting lesson! ;-) New comments/answers inlined …

On Fri, Jun 10, 2016 at 03:25:28PM +0000, Faccini, Bruno wrote:
Hello,
The intent of this patch is not to solve the corruptions for sure, but
only to avoid the concerned MEs/small-MDs LNet structs to be quite
frequently impacted due to their high allocation/free rate.

But that’s not what the patch description said :(
True. This is mainly because the original patch text has not been changed, but if this patch (originally to debug <size-128> kmem_cache corruptions) has been kept to be integrated this comes from our reflexion that this could also be an enhancement.

And again, putting them in a separate cache is not going to save much of
anything, given that your caches might have been merged together anyway.

This may also possibly help to save cycles due to high usage and
contention when using a generic kmem_cache (when they stay separate
from others, thanks for the precision!).

Have you measured this?
No, but I will try to measure it.


This isn't applicable for 4.7-rc at this time, _unless_ it fixes a bug,
which is why I pushed back on this.  If you want your own cache for
these variables, fine, I don't care, but that makes it a 4.8-rc1 patch
instead.
I have no problem with that.


hope that helps explain things better,
Yes, definitely.


greg k-h

Thanks,
Bruno.

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