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From: David Mosberger <davidm@napali.hpl.hp.com>
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Date: Wed, 19 Jun 2002 12:14:01 -0700
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Andries Brouwer <aebr@win.tue.nl>,
       Daniel Phillips <phillips@bonn-fries.net>, <Andries.Brouwer@cwi.nl>,
       Alexander Viro <viro@math.psu.edu>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH+discussion] symlink recursion
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>>>>> On Wed, 19 Jun 2002 11:55:23 -0700 (PDT), Linus Torvalds <torvalds@transmeta.com> said:

  Linus> Yes. But did you look at the stack frames of those things?
  Linus> It's something like 16 bytes for ext2_follow_link (it just
  Linus> calls directly back to the VFS layer), 20 bytes for
  Linus> vfs_follow_link(), and 56 for link_path_walk.

  Linux> ...

  Linus> But there are other numbers, like performance (sometimes
  Linus> linearizing recursion loses, sometimes it wins), or somebody
  Linus> doing the math on ia-64 and showing that the 100 bytes/level
  Linus> on x86 is actually more like 2kB on ia-64 and totally
  Linus> unacceptable.

Just to avoid starting false rumours: on ia-64, I see the following
(2.4.18, with gcc3.1):

	- ext2_follow_link():	 16 bytes/frame
	- vfs_follow_link():	 56 bytes/frame
	- link_path_walk():	128 bytes/frame
	---------------------	---------------
	total:			200 bytes/frame

Just about in line with what you'd expect given that registers are 64 bits.

	--david
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