Re: +atomic-improve-atomic_inc_unless_negative-atomic_dec_unless_positive.patch added to -mm tree
From: Oleg Nesterov
Date: Fri Mar 22 2013 - 09:06:45 EST
On 03/21, Eric Dumazet wrote:
> On Thu, 2013-03-21 at 19:30 +0100, Oleg Nesterov wrote:
> > To me, it would be better to kill atomic_inc_not_zero_hint() or unify
> > unify it with atomic_inc_not_zero(). But this is another story.
> git is your friend.
> I suggest you read 3f9d35b9514 changelog before killing it, thanks.
Thanks Eric for your friendly suggestion.
But I didn't mean we should kill this optimization. Yes, I am wondering
if we can avoid inc_not_zero_hint _or_ unify with add_unless. But let me
repeat, this is another story.
Perhaps I misread your previous email... I understood it as if you think
the patch I sent is wrong. No?
If you meant that get_write_access() can predict the current value of
i_writecount... how? And even if we could, why we cant/shouldnt try to
optimize the generic atomic_inc_unless_negative()?
So what did you actually mean?
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