lkml.org 
[lkml]   [2020]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v5 2/9] x86/split_lock: Avoid runtime reads of the TEST_CTRL MSR
Date
"Luck, Tony" <tony.luck@intel.com> writes:

> On Sun, Mar 15, 2020 at 01:05:10PM +0800, Xiaoyao Li wrote:
>> In a context switch from a task that is detecting split locks
>> to one that is not (or vice versa) we need to update the TEST_CTRL
>> MSR. Currently this is done with the common sequence:
>> read the MSR
>> flip the bit
>> write the MSR
>> in order to avoid changing the value of any reserved bits in the MSR.
>>
>> Cache the value of the TEST_CTRL MSR when we read it during initialization
>> so we can avoid an expensive RDMSR instruction during context switch.
>>
>> Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
>> Originally-by: Tony Luck <tony.luck@intel.com>
>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
>
> Is it bad form to Ack/Review patches originally by oneself?

Only if they are broken ....

\
 
 \ /
  Last update: 2020-03-23 18:07    [W:0.095 / U:29.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site