Re: [BENCHMARKS] Namesys VM patches improve kbuild

[Nick Piggin <piggin@cyberone.com.au>]

Andrew Morton wrote:

>Nick Piggin <piggin@cyberone.com.au> wrote:
>
>> By the way, what
>> do you think of this? Did I miss something non obvious?
>>
>> Seems to make little difference on the benchmarks. Without the patch,
>> the active list would generally be attacked more aggressively.
>>
>>
>>
>>[vm-fix-shrink-zone.patch  text/plain (2741 bytes)]
>>
>> Use the actual number of pages difference when trying to keep the inactive
>> list 1/2 the size of the active list (1/3 the size of all pages) instead of
>> a meaningless ratio.
>>
>
>Frankly, that `ratio' thing has always hurt my brain, so I left it as-is
>from 2.4 because it never caused any obvious problems.
>
>If we can put some clearer rationale behind what we're doing in there then
>great.
>

Hmm, I actually did misread it a bit. The ratio is:
nr_pages * zone->nr_active / (zone->nr_inactive * 2)
Which is nr_pages if the active list is size we want.

So its not so bad as I thought. Scaling by nr_pages would
seem to couple it strongly with free pages though. My
patch makes it more independent. No I don't know if thats
good or not, it would obviously need a lot of testing.


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