Re: Better active/inactive list balancing

[Mtrr Patt <mtrr.patt@gmail.com>]

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.


--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>