* Matt Mackall ([EMAIL PROTECTED]) wrote:
> On Fri, Jun 01, 2007 at 12:46:23PM -0400, Mathieu Desnoyers wrote:
> > * Matt Mackall ([EMAIL PROTECTED]) wrote:
> > > On Thu, May 31, 2007 at 03:42:50PM +0200, Andi Kleen wrote:
> > > > Mathieu Desnoyers <[EMAIL PROTECTED]> writes:
> > > >
> > > > > Reimplementation of the cond calls which uses a hash table to hold
> > > > > the active
> > > > > cond_calls. It permits to first arm a cond_call and then load
> > > > > supplementary
> > > > > modules that contain this cond_call.
> > > >
> > > > Hash table is probably overkill. This is a very very slow path
> > > > operation.
> > > > Can you simplify the code? Just a linked list of all the condcall
> > > > segments
> > > > should be enough and then walk it.
> > >
> > > I think it could be greatly simplified by using symbols instead of
> > > strings.
> > >
> > > That is, doing cond_call(foo, func()) rather than cond_call("foo",
> > > func()). Here foo is a structure or type holding the relevant info to
> > > deal with the cond_call infrastructure. For unoptimized architectures,
> > > it can simply be a bool, which will be faster.
> > >
> > > This has the added advantage that the compiler will automatically pick
> > > up any misspellings of these things. And it saves the space we'd use
> > > on the hash table too.
> > >
> >
> > The idea is interesting, but does not fit the problem: AFAIK, it will
> > not be possible to do multiple declarations of the same symbol, which is
> > needed whenever we want to declare a cond_call() more than once or to
> > embed it in an inline function.
>
> It's not clear to me why either of those things are necessary. An
> example please?
>
Case where we want to declare the same cond_call multiple times :
function_a(int var)
{
...
cond_call(profile_on, profile_hit(...));
...
}
function_b(int var, int var2)
{
...
cond_call(profile_on, profile_hit(...));
...
}
Case in inline function :
static inline myinlinefct()
{
...
cond_call(profile_on, profile_hit(...));
...
}
somefct()
{
...
myinlinefct();
...
myinlinefct();
...
}
Those will result in multiple declarations of the cond_call.
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
