[lkml]   [2014]   [Oct]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 0/4] Convert khugepaged to a task_work function
On 10/28/2014 08:12 AM, Andi Kleen wrote:
> Alex Thorlton <> writes:
>> Last week, while discussing possible fixes for some unexpected/unwanted behavior
>> from khugepaged (see: several people
>> mentioned possibly changing changing khugepaged to work as a task_work function
>> instead of a kernel thread. This will give us finer grained control over the
>> page collapse scans, eliminate some unnecessary scans since tasks that are
>> relatively inactive will not be scanned often, and eliminate the unwanted
>> behavior described in the email thread I mentioned.
> With your change, what would happen in a single threaded case?
> Previously one core would scan and another would run the workload.
> With your change both scanning and running would be on the same
> core.
> Would seem like a step backwards to me.

It's not just scanning, either.

Memory compaction can spend a lot of time waiting on
locks. Not consuming CPU or anything, but just waiting.

I am not convinced that moving all that waiting to task
context is a good idea.

 \ /
  Last update: 2014-10-28 14:41    [W:0.189 / U:5.800 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site