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Date: Thu, 13 Aug 2015 13:26:01 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>, Al Viro <viro@zeniv.linux.org.uk>,
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Subject: Re: get_vmalloc_info() and /proc/meminfo insanely expensive
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On Wed, 12 Aug 2015 22:52:44 -0700 Linus Torvalds <torvalds@linux-foundation.org> wrote:

> Looking at that mm/vmalloc.c file, the locking is pretty odd. It looks
> pretty strange in setup_vmalloc_vm(), for example. If that newly
> allocated "va" that we haven't even exposed to anybody yet has its
> address or size changed, we're screwed in so many ways.
> 
> I get the feeling this file should be rewritten. But that's not going
> to happen.

Nick Piggin started doing a rewrite in 2008 but it was never completed
(https://lwn.net/Articles/285341/).