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SubjectRe: [PATCH 03/11] vfs: Don't allow overwriting mounts in the current mount namespace
Stephen Rothwell <sfr@canb.auug.org.au> writes:

> On Tue, 18 Feb 2014 14:20:29 -0800 Linus Torvalds <torvalds@linux-foundation.org> wrote:
>>
>> For this kind of function return value it actually tends to work very
>> well, and in fact often generates slightly better code than "int". So
>> I don't _hate_ bool, and we've certainly had a lot more use creep in
>> lately, but I also don't really see "bool" as much of an upside.
>
> And in function declarations, it makes it very obvious that the function
> is not one of our "return 0 or -ERROR" ones.

So I played with this instance in particular. The only difference winds
up being by the bool version uses byte instructions on %al and %bl
instead of their 32 bit interger equivalents on %eax and %ebx.

I also benchmarked the difference and on the most sensitive test I could
find. will-it-scale/unlink2 (aka create,close,unlink each process in a
separate directory). There were no measurable performance differences.

So for purposes of better documentation I have changed the function, and
I will repost my patches shortly.

Eric


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