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* rss MM_FILEPAGES statistics value issue in kernel memory remap_pfn_range function.
@ 2014-09-24  9:55 xiaowen.liu
  0 siblings, 0 replies; only message in thread
From: xiaowen.liu @ 2014-09-24  9:55 UTC (permalink / raw)
  To: majordomo; +Cc: linux-mm

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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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