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Date: Sun, 31 May 2009 00:13:18 +0100
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: "Larry H." <research@subreption.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>, Rik van Riel <riel@redhat.com>,
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       Linus Torvalds <torvalds@osdl.org>, linux-mm@kvack.org,
       Ingo Molnar <mingo@redhat.com>, pageexec@freemail.hu,
       Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [patch 0/5] Support for sanitization flag in low-level page
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> I was pointing out that the 'those test and jump/call branches have
> performance hits' argument, while nonsensical, applies to kzfree and
> with even more negative connotations (deeper call depth, more test
> branches used in ksize and kfree, lack of pointer validation).

But they only apply to kzfree - there isn't a cost to anyone else. You've
move the decision to compile time which for the fast path stuff when you
just want to clear keys and other oddments is a big win.