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From: "xiaowen.liu@freescale.com" <xiaowen.liu@freescale.com>
To: "majordomo@kvack.org" <majordomo@kvack.org>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: rss MM_FILEPAGES statistics value issue in kernel memory remap_pfn_range function.
Date: Wed, 24 Sep 2014 09:55:56 +0000	[thread overview]
Message-ID: <e71eda4ca6734380876f0ddbb4e4f258@DM2PR03MB432.namprd03.prod.outlook.com> (raw)

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Hi majordomo,

Sorry to bother you.

I noticed that there are two functions provided to map memory to user space from kernel: remap_pfn_range and vm_insert_page.
There is one difference that vm_insert_page increase task rss MM_FILEPAGES value. But remap_pfn_range doesn't.
The issue is the munmap function will call zap_pte_range to decrease task rss MM_FILEPAGES value.
So, the task rss MM_FILEPAGES value increase and decrease doesn't match.

And there are many places in kernel driver call remap_pfn_range to map memory to user space.

I think remap_pfn_range should also increase task rss MM_FILEPAGES value.

If there is any misunderstanding, please correct me.
Thanks.


BestRegards,
Ivan.liu









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                 reply	other threads:[~2014-09-24  9:56 UTC|newest]

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