Re: RFC: Easy-Reclaimable LRU list

[Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

(2012/06/22 15:57), Minchan Kim wrote:
> Hi John,
>
> On 06/22/2012 04:21 AM, John Stultz wrote:
>
>> On 06/18/2012 10:49 PM, Minchan Kim wrote:
>>> Hi everybody!
>>>
>>> Recently, there are some efforts to handle system memory pressure.
>>>
>>> 1) low memory notification - [1]
>>> 2) fallocate(VOLATILE) - [2]
>>> 3) fadvise(NOREUSE) - [3]
>>>
>>> For them, I would like to add new LRU list, aka "Ereclaimable" which
>>> is opposite of "unevictable".
>>> Reclaimable LRU list includes _easy_ reclaimable pages.
>>> For example, easy reclaimable pages are following as.
>>>
>>> 1. invalidated but remained LRU list.
>>> 2. pageout pages for reclaim(PG_reclaim pages)
>>> 3. fadvise(NOREUSE)
>>> 4. fallocate(VOLATILE)
>>>
>>> Their pages shouldn't stir normal LRU list and compaction might not
>>> migrate them, even.
>>> Reclaimer can reclaim Ereclaimable pages before normal lru list and
>>> will avoid unnecessary
>>> swapout in anon pages in easy-reclaimable LRU list.
>>
>> I was hoping there would be further comment on this by more core VM
>> devs, but so far things have been quiet (is everyone on vacation?).
>
>
> At least, there are no dissent comment until now.
> Let be a positive. :)

I think this is interesting approach. Major concern is how to guarantee EReclaimable
pages are really EReclaimable...Do you have any idea ? madviced pages are really
EReclaimable ?

A (very) small concern is will you use one more page-flags for this ? ;)

Thanks,
-Kame