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From: Mtrr Patt <mtrr.patt@gmail.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Michal Hocko <mhocko@suse.cz>, Mel Gorman <mgorman@suse.de>,
	linux-mm@kvack.org
Subject: Re: Better active/inactive list balancing
Date: Wed, 01 May 2013 14:55:53 +0800	[thread overview]
Message-ID: <5180BC79.8080101@gmail.com> (raw)
In-Reply-To: <20130430163230.GB1229@cmpxchg.org>

Hi Johannes,
On 05/01/2013 12:32 AM, Johannes Weiner wrote:
> On Sat, Apr 27, 2013 at 02:20:54PM +0800, Mtrr Patt wrote:
>> cc linux-mm
>>
>> On 04/27/2013 02:19 PM, Mtrr Patt wrote:
>>> Hi Johannes,
>>>
>>> http://lwn.net/Articles/495543/
>>>
>>> This link said that "When active pages are considered for
>>> eviction, they are first moved to the inactive list and unmapped
>> >from the address space of the process(es) using them. Thus, once a
>>> page moves to the inactive list, any attempt to reference it will
>>> generate a page fault; this "soft fault" will cause the page to be
>>> removed back to the active list."
>>>
>>> Why I can't find the codes unmap during page moved from active
>>> list to inactive list?
> Most architectures have the hardware track the referenced bit in the
> page tables, but some don't.  For them, page_referenced_one() will
> mark the mapping read-only when clearing the referenced/young bit and
> the page fault handler will set the bit manually.

Thanks for your response. ;-) So the article is not against more common 
case, isn't it?

> When mapped pages reach the end of the inactive list and have that bit
> set, they get activated, see page_check_references().

It seems that the page should trigger page fault twice and 
page_check_references can active it.


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  reply	other threads:[~2013-05-01  6:56 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <517B6DF5.70402@gmail.com>
2013-04-27  6:20 ` Better active/inactive list balancing Mtrr Patt
2013-04-30 16:32   ` Johannes Weiner
2013-05-01  6:55     ` Mtrr Patt [this message]
2013-05-01 15:21       ` Johannes Weiner
2013-05-01 23:35         ` Mtrr Patt

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