Re: [RFC] vfs: don't bother clearing close_on_exec bit for unused fds

From: Linus Torvalds
Date: Tue Nov 03 2015 - 17:45:10 EST


On Tue, Nov 3, 2015 at 1:41 AM, Rasmus Villemoes
<linux@xxxxxxxxxxxxxxxxxx> wrote:
>
> I'm sure I've missed something, hence the RFC. But if not, there's
> probably also a few memsets which become redundant. And the
> __set_close_on_exec part should probably be its own patch...

The patch looks fine to me. I'm not sure the __set_close_on_exec part
even makes sense, because if you set that bit, it usually really *is*
clear before, so testing it beforehand is just pointless. And if
somebody really keeps setting the bit, they are doing something stupid
anyway..

So I have nothing against the patch, but I do wonder how much it
matters. If there isn't a noticeable performance win, I'd almost
rather just keep the close-on-exec bitmap up-to-date. Hmm?

Linus
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