From: Dan Magenheimer <dan.magenheimer@oracle.com>
To: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Konrad Wilk <konrad.wilk@oracle.com>,
Seth Jennings <sjenning@linux.vnet.ibm.com>,
Nitin Gupta <ngupta@vflare.org>,
Nebojsa Trpkovic <trx.lists@gmail.com>,
minchan@kernel.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Chris Mason <chris.mason@oracle.com>
Subject: RE: [PATCH] mm: implement WasActive page flag (for improving cleancache)
Date: Thu, 26 Jan 2012 21:15:16 -0800 (PST) [thread overview]
Message-ID: <22f6781b-9cc4-4857-b3e1-e2d9f595f64d@default> (raw)
In-Reply-To: <4F221AFE.6070108@redhat.com>
> From: Rik van Riel [mailto:riel@redhat.com]
> Subject: Re: [PATCH] mm: implement WasActive page flag (for improving cleancache)
>
> On 01/26/2012 09:43 PM, Dan Magenheimer wrote:
>
> > Maybe the Active page bit could be overloaded with some minor
> > rewriting? IOW, perhaps the Active bit could be ignored when
> > the page is moved to the inactive LRU? (Confusing I know, but I am
> > just brainstorming...)
>
> The PG_referenced bit is already overloaded. We keep
> the bit set when we move a page from the active to the
> inactive list, so a page that was previously active
> only needs to be referenced once to become active again.
>
> The LRU bits (PG_lru, PG_active, etc) are needed to
> figure out which LRU list the page is on. I don't
> think we can overload those...
I suspected that was true, but was just brainstorming.
Thanks for confirming.
Are there any other page bits that are dont-care when
a page is on an LRU list?
I'd also be interested in your/RedHat's opinion on the
64-bit vs 32-bit market. Will RHEL7 even support 32-bit?
Dan
next prev parent reply other threads:[~2012-01-27 5:15 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-25 21:58 [PATCH] mm: implement WasActive page flag (for improving cleancache) Dan Magenheimer
2012-01-26 17:28 ` Dave Hansen
2012-01-26 21:28 ` Dan Magenheimer
2012-01-27 0:31 ` Andrew Morton
2012-01-27 0:56 ` Dan Magenheimer
2012-01-27 1:15 ` Andrew Morton
2012-01-27 2:43 ` Dan Magenheimer
2012-01-27 3:33 ` Rik van Riel
2012-01-27 5:15 ` Dan Magenheimer [this message]
2012-01-30 8:57 ` KAMEZAWA Hiroyuki
2012-01-30 22:03 ` Dan Magenheimer
2012-01-27 13:43 ` James Bottomley
2012-01-27 17:32 ` Dan Magenheimer
2012-01-27 17:54 ` James Bottomley
2012-01-27 18:46 ` Dan Magenheimer
2012-01-27 21:49 ` James Bottomley
2012-01-29 0:50 ` Rik van Riel
2012-01-29 22:25 ` James Bottomley
2012-01-27 3:28 ` Rik van Riel
2012-01-27 5:11 ` Dan Magenheimer
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