lkml.org 
[lkml]   [2012]   [Apr]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 10/16] KVM: MMU: fask check whether page is writable
On 04/17/2012 06:55 AM, Xiao Guangrong wrote:
> On 04/16/2012 07:47 PM, Avi Kivity wrote:
>
> > On 04/16/2012 01:20 PM, Xiao Guangrong wrote:
> >>>>
> >>>> It is used to avoid the unnecessary overload
> >>>
> >>> It's overloading me :(
> >>>
> >>
> >>
> >> Sorry.
> >>
> >
> > The trick is to send those in separate patchset so the maintainer
> > doesn't notice.
> >
>
>
> Thanks for your suggestion, i will pay more attention on it in the
> further.
>
> For this patch, what did you mean of "those"? You mean the whole
> rmap.PTE_LIST_WP_BIT (fast check for shadow page table write protection
> and host write protection) or just about host_page_write_protect
> (for KSM only)?

All of it. Let's start with just modifying sptes concurrently and only
later add reading bits from rmap concurrently, if it proves necessary.

>
> If we do not have rmap.PTE_LIST_WP_BIT, there may have regression on
> shadow mmu.
>
> Hmm, do i need implement rmap.PTE_LIST_WP_BIT, then fast page fault?

Let's try to measure the effect without rmap.PTE_LIST_WP_BIT. Usually
PTE chains for page tables are short so the effect would be small. Of
course we can't tell about all guest.

--
error compiling committee.c: too many arguments to function



\
 
 \ /
  Last update: 2012-04-17 09:45    [W:0.081 / U:0.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site