[Tmem-devel] [RFC PATCH 1/4] (Take 2): tmem: Core API between kernel and tmem

[Dan Magenheimer]

> From: Rik van Riel [mailto:riel at redhat.com]
> Subject: Re: [RFC PATCH 1/4] (Take 2): tmem: Core API between 
> 
> Dan Magenheimer wrote:
> > Tmem [PATCH 1/4] (Take 2): Core API between kernel and tmem
> 
> I like the cleanup of your patch series.

Thanks much, but credit goes to Jeremy for suggesting this
very clean tmem_ops interface.
 
> However, what remains is a fair bit of code.

Yes, though much of the LOC is for clean layering and
readability.  (Nearly half of the patch is now comments.)

> It would be good to have performance numbers before
> deciding whether or not to merge all this code.

On one benchmark that I will be presenting at Linux Symposium
(8 dual-VCPU guests with 384MB of initial memory and doing
self-ballooning to constrain memory, each guest compiling
Linux continually; quad-core-dual-thread Nehalem processor
with 4GB physical RAM) I am seeing savings of ~300 IO/sec
at an approximate cost of 0.1%-0.2% of one CPU.  But
I admit much more benchmarking needs to be done.

Thanks,
Dan