lkml.org 
[lkml]   [2019]   [Apr]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: Thoughts on simple scanner approach for free page hinting
    From
    Date
    On 09.04.19 04:44, Michael S. Tsirkin wrote:
    > On Fri, Apr 05, 2019 at 05:09:45PM -0700, Alexander Duyck wrote:
    >> In addition we will need some way to identify which pages have been
    >> hinted on and which have not. The way I believe easiest to do this
    >> would be to overload the PageType value so that we could essentially
    >> have two values for "Buddy" pages. We would have our standard "Buddy"
    >> pages, and "Buddy" pages that also have the "Offline" value set in the
    >> PageType field. Tracking the Online vs Offline pages this way would
    >> actually allow us to do this with almost no overhead as the mapcount
    >> value is already being reset to clear the "Buddy" flag so adding a
    >> "Offline" flag to this clearing should come at no additional cost.
    >
    > It bothers me a bit that this doesn't scale to multiple hint types
    > if we ever need them. Would it be better to have two
    > free lists: hinted and non-hinted one?

    That would imply having to change all places trying to allocate memory
    to have a look at both lists? I think that could be factored out. I
    assume keeping track of the amount of pages would feel more naturally
    than having split counters for the existing lists.

    I think I'd actually prefer something like that, avoiding mixing page
    types and working with different types per list.

    --

    Thanks,

    David / dhildenb

    \
     
     \ /
      Last update: 2019-04-09 09:06    [W:7.442 / U:0.060 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site