Re: [PATCH v2 06/12] KVM: MMU: introduce a static table to map guestaccess to spte access

From: Xiao Guangrong
Date: Thu Jan 24 2013 - 21:46:34 EST


On 01/25/2013 08:15 AM, Marcelo Tosatti wrote:
> On Wed, Jan 23, 2013 at 06:07:20PM +0800, Xiao Guangrong wrote:
>> It makes set_spte more clean and reduces branch prediction
>>
>> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
>> ---
>> arch/x86/kvm/mmu.c | 37 ++++++++++++++++++++++++++-----------
>> 1 files changed, 26 insertions(+), 11 deletions(-)
>
> Don't see set_spte as being a performance problem?
> IMO the current code is quite simple.

Yes, this is not a performance problem.

I just dislike this many continuous "if"-s in the function:

if (xxx)
xxx
if (xxx)
xxx
....

Totally, it has 7 "if"-s before this patch.

Okay, if you think this is unnecessary, i will drop this patch. :)

--
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/