linux-kernel - Re: tracking memory usage/leak in "inactive" field in /proc/meminfo?

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Message-ID: <4B7B0D75.50808@nortel.com>
Date:	Tue, 16 Feb 2010 15:26:13 -0600
From:	"Chris Friesen" <cfriesen@...tel.com>
To:	Rik van Riel <riel@...hat.com>
CC:	Minchan Kim <minchan.kim@...il.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-mm@...ck.org, Balbir Singh <balbir@...ux.vnet.ibm.com>
Subject: Re: tracking memory usage/leak in "inactive" field in /proc/meminfo?

On 02/16/2010 11:12 AM, Rik van Riel wrote:
> On 02/16/2010 11:52 AM, Chris Friesen wrote:
>> On 02/15/2010 11:00 AM, Rik van Riel wrote:
> 
>>> Removal from the LRU is done from the page freeing code, on
>>> the final free of the page.
> 
>> There are a bunch of inline functions involved, but I think the chain
>> from page_remove_rmap() back up to unmap_vmas() looks like this:
>>
>> page_remove_rmap
>> zap_pte_range
>> zap_pmd_range
>> zap_pud_range
>> unmap_page_range
>> unmap_vmas
>>
>> So in this scenario, where do the pages actually get removed from the
>> LRU list (assuming that they're not in use by anyone else)?
> 
> __page_cache_release


For the backtrace scenario I posted it seems like it might actually be
release_pages().  There seems to be a plausible call chain:

__ClearPageLRU
release_pages
free_pages_and_swap_cache
tlb_flush_mmu
tlb_remove_page
zap_pte_range

Does that seem right?  In this case, tlb_remove_page() is called right
after page_remove_rmap() which ultimately results in clearing the
PageAnon bit.

Chris
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