Re: [PATCH] shrinker support for the mmu cache

[Izik Eidus <izike@qumranet.com>]

Anthony Liguori wrote:
> Izik Eidus wrote:
>> this patch simply register the mmu cache with the shrinker.
>
> Please inline patches in the future as it makes it easier to review.  
I knew this time will come when ppl will force me to send patchs inline 
(will happen next time )... :)

> The implementation looks good and I think it's a good idea.
>
> One is that there is one shrinker for all VMs but you run through the 
> list of VMs in order.  This means the first VM in the list is most 
> frequently going to be shrunk down to KVM_MIN_ALLOC_MMU_PAGES.  This 
> seems unfair and potentially dangerous.  The shrinker can be triggered 
> potentially by the growth of the MMU cache on other VMs.
>
> I think in the least, you should attempt to go through the VMs in a 
> round-robin fashion to ensure that if you shrink one VM, the next time 
> you'll shrink a different VM.

you are 100% right, i will do that.

>
> The other thing I wonder about is whether DEFAULT_SEEKS is the best 
> value to use.  On the one hand, a guest page fault is probably not as 
> expensive as reclaiming something from disk.  On the other hand, NPT 
> guests are likely to be very sensitive to evicting things from the 
> shadow page cache.  I would think it's pretty clear that in the NPT 
> case, the MMU cache should have a higher seek cost than the default.

let me look at this, i think you have a case

>
> Regards,
>
> Anthony Liguori
>
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