From: Rik van Riel <riel@redhat.com>
To: Bob Liu <bob.liu@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>, Minchan Kim <minchan@kernel.org>,
Luigi Semenzato <semenzato@google.com>,
Linux-MM <linux-mm@kvack.org>,
hnaz@cmpxchg.org
Subject: Re: swap, compress, discard: what's in the future?
Date: Thu, 09 Jan 2014 11:41:34 -0500 [thread overview]
Message-ID: <52CED13E.50700@redhat.com> (raw)
In-Reply-To: <52CE5B58.8080203@oracle.com>
On 01/09/2014 03:18 AM, Bob Liu wrote:
>
> On 01/07/2014 09:45 PM, Rik van Riel wrote:
>> On 01/07/2014 01:33 AM, Bob Liu wrote:
>>> On Tue, Jan 7, 2014 at 11:01 AM, Minchan Kim <minchan@kernel.org> wrote:
>>
>>>> Your statement makes sense to me but unfortunately, current VM doesn't
>>>> consider everything you mentioned.
>>>> It is just based on page access recency by approximate LRU logic +
>>>> some heuristic(ex, mapped page and VM_EXEC pages are more precious).
>>>
>>> It seems that the ARC page replacement algorithm in zfs have good
>>> performance and more intelligent.
>>> http://en.wikipedia.org/wiki/Adaptive_replacement_cache
>>> Is there any history reason of linux didn't implement something like
>>> ARC as the page cache replacement algorithm?
>>
>> ARC by itself was quickly superceded by CLOCK-Pro, which
>> looks like it would be even better.
>>
>> Johannes introduces an algorithm with similar properties
>> in his "thrash based page cache replacement" patch series.
>>
>
> But it seems you and Peter have already implemented CLOCK-Pro and CART
> page cache replacement many years ago. Why they were not get merged at
> that time?
Scalability concerns, lack of time, and the VM not being
ready to take the code.
The split LRU code makes it much more logical to merge a
replacement scheme that is suitable for second level
caches, because the anonymous memory is in an LRU scheme
that is more suitable to its kind of usage.
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prev parent reply other threads:[~2014-01-09 16:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-07 2:31 Luigi Semenzato
2014-01-07 3:01 ` Minchan Kim
2014-01-07 6:33 ` Bob Liu
2014-01-07 7:13 ` Minchan Kim
2014-01-07 13:45 ` Rik van Riel
2014-01-09 8:18 ` Bob Liu
2014-01-09 16:41 ` Rik van Riel [this message]
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