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SubjectRe: Inline local_bh_disable when TRACE_IRQFLAGS

* Herbert Xu <herbert@gondor.apana.org.au> wrote:

> On Wed, Dec 19, 2007 at 12:31:52PM +0100, Ingo Molnar wrote:
> >
> > > So I'm wondering if it would be reasonable to make it out-of-line
> > > when TRACE_IRQFLAGS is off. This may make a difference because
> > > the networking stack is a frequent user of local_bh_disable and
> > > local_bh_enable.
> >
> > do you mean to make it inline again?
>
> Yes I meant in-line :)

if that decreases code size then i guess we could do that.

> > (btw., generally i think local_bh_disable() is a poor API because it
> > is opaque about the data structure dependency that it governs.
> > Explicit exclusion rules generally work better.)
>
> I see where you're coming from especially with your preemptible
> softirq work. However I'm mostly thinking about the existing callers
> of local_bh_disable in the networking stack.

yeah, i was just commenting on the general concept of 'naked'
local_bh_disable(). And just to make it clear: with that i'm not
implying anything about the quality of the networking code - networking
is one of the cleanest [if not the cleanest] subsystems in the kernel.

It's just that it's long term more useful for us if our "global scope"
APIs have direct, programmatic relationship to the data structures /
data flow they control. So i'd love to have the same flow/performance,
just coded a bit more explicitly. [preempt_disable() for example has
similar issues.]

Ingo


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