Re: [RFC 6/8] In order putback lru core

From: Minchan Kim
Date: Wed Apr 27 2011 - 19:59:23 EST


Hi Rik,

On Thu, Apr 28, 2011 at 8:46 AM, Rik van Riel <riel@xxxxxxxxxx> wrote:
> On 04/26/2011 12:25 PM, Minchan Kim wrote:
>
>> But this approach has a problem on contiguous pages.
>> In this case, my idea can not work since friend pages are isolated, too.
>> It means prev_page->next == next_page always is false and both pages are
>> not
>> LRU any more at that time. It's pointed out by Rik at LSF/MM summit.
>> So for solving the problem, I can change the idea.
>> I think we don't need both friend(prev, next) pages relation but
>> just consider either prev or next page that it is still same LRU.
>
>> Any comment?
>
> If the friend pages are isolated too, then your condition
> "either prev or next page that it is still same LRU" is
> likely to be false, no?

H - P1 - P2 - P3 - P4 - P5 - P6 - P7 - P8 - P9 - P10 - T

assume : we isolate pages P3~P7 and we consider only next pointer.

H - P1 - P2 - P8 - P9 - P10 - T

If we start to putback P7 as starting point, next P8 is valid so,

H - P1 - P2 - P7 - P8 - P9 - P10 - T
Then, if we consider P6, next P7 is valid, too. So,

H - P1 - P2 - P6 - P7 - P8 - P9 - P10 - T

continue until P3.


--
Kind regards,
Minchan Kim
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