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SubjectRe: [PATCH] introduce sig_needs_tasklist() helper
On Tue, Feb 21, 2006 at 09:25:25PM +0300, Oleg Nesterov wrote:
> "Paul E. McKenney" wrote:
> >
> > On Sat, Feb 18, 2006 at 09:12:04PM +0300, Oleg Nesterov wrote:
> > > +#define sig_needs_tasklist(sig) \
> > > + (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_STOP_MASK | M(SIGCONT)))
> > > +
> >
> > Seems to me to be an improvement, but why not also encapsulate the
> > lock acquisition, something like:
> >
> > static inline int sig_tasklist_lock(int sig)
> > {
> > if (unlikely(sig_needs_tasklist(sig)) {
> > read_lock(&tasklist_lock);
> > return 1;
> > }
> > return 0;
> > }
> >
> > static inline void sig_tasklist_unlock(int acquired_tasklist_lock)
> > {
> > if (acquired_tasklist_lock)
> > read_unlock(&tasklist_lock);
> > }
>
> I hope we will have
>
> #define sig_needs_tasklist(sig) (sig == SIGCONT)
>
> really soon (I planned to submit the final bits today, but
> for some stupid reasons I can't do anything till weekend),
> so I think it's better to kill 'acquired_tasklist_lock' and
> just do:
>
> void sig_tasklist_lock(sig)
> {
> if (sig_needs_tasklist(sig))
> read_lock(&tasklist_lock);
> }
>
> void sig_tasklist_unlock(sig)
> {
> if (sig_needs_tasklist(sig));
> read_unlock(&tasklist_lock);
> }

Even better!

Thanx, Paul
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