Re: [RFC v1][PATCH]page_fault retry with NOPAGE_RETRY

[KOSAKI Motohiro]

> Furthermore, /proc code usually isn't written with performance in mind,
> so its usually simple and robust code. Adding it to a 'hot'-path like
> you're doing doesn't seem advisable.
> 
> Also, releasing and re-acquiring mmap_sem can significantly add to the
> cacheline bouncing that thing already has.

Interesting.

I tryed to demonstration /proc slowness.

1. make many process
	$ nice ./hackbench 120 process 10000

2. read /proc
	$ time ps -ef

	0.16s user 0.57s system 1% cpu 46.859 total


HAHAHA!
That is really slow over my expected.



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