From: Peter Zijlstra <peter@programming.kicks-ass.net>
To: Magnus Damm <magnus.damm@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
Magnus Damm <magnus@valinux.co.jp>,
Linux Kernel <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 00/03] Unmapped: Separate unmapped and mapped pages
Date: Sat, 11 Mar 2006 21:58:14 +0100 [thread overview]
Message-ID: <1142110694.2928.6.camel@lappy> (raw)
In-Reply-To: <aec7e5c30603100519l5a68aec3ub838ac69a734a46b@mail.gmail.com>
On Fri, 2006-03-10 at 14:19 +0100, Magnus Damm wrote:
> On 3/10/06, Arjan van de Ven <arjan@infradead.org> wrote:
> > > Apply on top of 2.6.16-rc5.
> > >
> > > Comments?
> >
> >
> > my big worry with a split LRU is: how do you keep fairness and balance
> > between those LRUs? This is one of the things that made the 2.4 VM suck
> > really badly, so I really wouldn't want this bad...
>
> Yeah, I agree this is important. I think linux-2.4 tried to keep the
> LRU list lengths in a certain way (maybe 2/3 of all pages active, 1/3
> inactive). In 2.6 there is no such thing, instead the number of pages
> scanned is related to the current scanning priority.
This sounds wrong, the active and inactive lists are balanced to a 1:1
ratio. This is happens because the scan speed is directly proportional
to the size of the list. Hence the largest list will shrink fastest -
this gives a natural balance to equal sizes.
Peter
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peter@programming.kicks-ass.net>
To: Magnus Damm <magnus.damm@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
Magnus Damm <magnus@valinux.co.jp>,
Linux Kernel <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 00/03] Unmapped: Separate unmapped and mapped pages
Date: Sat, 11 Mar 2006 21:58:14 +0100 [thread overview]
Message-ID: <1142110694.2928.6.camel@lappy> (raw)
In-Reply-To: <aec7e5c30603100519l5a68aec3ub838ac69a734a46b@mail.gmail.com>
On Fri, 2006-03-10 at 14:19 +0100, Magnus Damm wrote:
> On 3/10/06, Arjan van de Ven <arjan@infradead.org> wrote:
> > > Apply on top of 2.6.16-rc5.
> > >
> > > Comments?
> >
> >
> > my big worry with a split LRU is: how do you keep fairness and balance
> > between those LRUs? This is one of the things that made the 2.4 VM suck
> > really badly, so I really wouldn't want this bad...
>
> Yeah, I agree this is important. I think linux-2.4 tried to keep the
> LRU list lengths in a certain way (maybe 2/3 of all pages active, 1/3
> inactive). In 2.6 there is no such thing, instead the number of pages
> scanned is related to the current scanning priority.
This sounds wrong, the active and inactive lists are balanced to a 1:1
ratio. This is happens because the scan speed is directly proportional
to the size of the list. Hence the largest list will shrink fastest -
this gives a natural balance to equal sizes.
Peter
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next prev parent reply other threads:[~2006-03-11 20:58 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-10 3:44 [PATCH 00/03] Unmapped: Separate unmapped and mapped pages Magnus Damm
2006-03-10 3:44 ` Magnus Damm
2006-03-10 3:44 ` [PATCH 01/03] Unmapped: Implement two LRU:s Magnus Damm
2006-03-10 3:44 ` Magnus Damm
2006-03-10 19:16 ` Christoph Lameter
2006-03-10 19:16 ` Christoph Lameter
2006-03-11 12:14 ` Magnus Damm
2006-03-11 12:14 ` Magnus Damm
2006-03-10 3:44 ` [PATCH 02/03] Unmapped: Modify LRU behaviour Magnus Damm
2006-03-10 3:44 ` Magnus Damm
2006-03-10 3:44 ` [PATCH 03/03] Unmapped: Add guarantee code Magnus Damm
2006-03-10 3:44 ` Magnus Damm
2006-03-10 4:57 ` Nick Piggin
2006-03-10 4:57 ` Nick Piggin
2006-03-10 6:04 ` Magnus Damm
2006-03-10 6:04 ` Magnus Damm
2006-03-10 15:41 ` Chandra Seetharaman
2006-03-10 15:41 ` Chandra Seetharaman
2006-03-11 12:29 ` Magnus Damm
2006-03-11 12:29 ` Magnus Damm
2006-03-15 15:32 ` Chandra Seetharaman
2006-03-15 15:32 ` Chandra Seetharaman
2006-03-10 4:55 ` [PATCH 00/03] Unmapped: Separate unmapped and mapped pages Nick Piggin
2006-03-10 4:55 ` Nick Piggin
2006-03-10 5:55 ` Magnus Damm
2006-03-10 5:55 ` Magnus Damm
2006-03-10 7:52 ` Arjan van de Ven
2006-03-10 7:52 ` Arjan van de Ven
2006-03-10 13:19 ` Magnus Damm
2006-03-10 13:19 ` Magnus Damm
2006-03-10 14:05 ` Arjan van de Ven
2006-03-10 14:05 ` Arjan van de Ven
2006-03-11 11:52 ` Magnus Damm
2006-03-11 11:52 ` Magnus Damm
2006-03-11 20:58 ` Peter Zijlstra [this message]
2006-03-11 20:58 ` Peter Zijlstra
2006-03-13 2:28 ` Magnus Damm
2006-03-13 2:28 ` Magnus Damm
2006-03-10 12:22 ` Peter Zijlstra
2006-03-10 12:22 ` Peter Zijlstra
2006-03-10 13:38 ` Magnus Damm
2006-03-10 13:38 ` Magnus Damm
2006-03-11 21:08 ` Peter Zijlstra
2006-03-11 21:08 ` Peter Zijlstra
2006-03-13 3:05 ` Magnus Damm
2006-03-13 3:05 ` Magnus Damm
2006-03-10 19:12 ` Christoph Lameter
2006-03-10 19:12 ` Christoph Lameter
2006-03-11 11:56 ` Magnus Damm
2006-03-11 11:56 ` Magnus Damm
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