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From: Hugh Dickins <hughd@google.com>
To: PINTU KUMAR <pintu_agarwal@yahoo.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [Help] : RSS/PSS showing 0 during smaps for Xorg
Date: Wed, 25 Jan 2012 16:59:41 -0800 (PST)	[thread overview]
Message-ID: <alpine.LSU.2.00.1201251623340.2141@eggly.anvils> (raw)
In-Reply-To: <1327468926.52380.YahooMailNeo@web162002.mail.bf1.yahoo.com>

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1719 bytes --]

On Tue, 24 Jan 2012, PINTU KUMAR wrote:
>  
> Is there a way to convert our mapped pages to a normal pages. I tried pfn_to_page() but no effect.
> I mean the page is considered normal only if it is associated with "struct page" right???
> Is is possible to convert these pages to a normal struct pages so that we can get the Rss/Pss value??

I don't understand why you are so anxious to see non-0 numbers there.

I don't know if the pages you are mapping with remap_pfn_range() are
ordinary pages in normal memory, and so already have struct pages, or not.

>  
> Also, the VM_PFNMAP is being set for all dirvers during remap_pfn_range and stills shows Rss/Pss for other drivers.

I'm surprised.  It is possible to set up a private-writable VM_PFNMAP area,
which can then contain ordinary private copies of the underlying pages,
and these copies will count to Rss.  But I thought that was very unusual.

You don't mention which drivers these are that use remap_pfn_range yet
show Rss (and I don't particularly want to spend time researching them).

I can see three or four places in drivers/ where VM_PFNMAP is set,
perhaps without going through remap_pfn_range(): that seems prone
to error, I wouldn't recommend going that route.

> Then why it is not shown for our driver?
> How to avoid remap_pfn_range to not to set VM_PFNMAP for our driver?

If these are ordinary pages with struct pages, then you could probably
use a loop of vm_insert_page()s to insert them at mmap time, or a fault
routine to insert them on fault.  But as I said, I don't know if this
memory is part of the ordinary page pool or not.

Really, the question has to be, why do you need to see non-0s there?

Hugh

  reply	other threads:[~2012-01-26  1:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1327310360.96918.YahooMailNeo@web162003.mail.bf1.yahoo.com>
2012-01-23 10:15 ` [Help] : RSS/PSS showing 0 during smaps for Xorg PINTU KUMAR
2012-01-23 19:31   ` Hugh Dickins
2012-01-25  5:22     ` PINTU KUMAR
2012-01-26  0:59       ` Hugh Dickins [this message]
2012-01-30  8:42         ` PINTU KUMAR
2012-01-30 18:49           ` Hugh Dickins
2012-02-01 14:49             ` PINTU KUMAR
2012-02-02  5:20               ` Hugh Dickins

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