Re: [PATCH -next v2 0/5] ipc/sem: semop(2) improvements

[Davidlohr Bueso]

On Mon, 19 Sep 2016, Manfred Spraul wrote:
> On 09/18/2016 09:11 PM, Davidlohr Bueso wrote:

> > Davidlohr Bueso (5):
> >   ipc/sem: do not call wake_sem_queue_do() prematurely
> The only patch that I don't like.
> Especially: patch 2 of the series removes the wake_up_q from the 
> function epilogue.
> So only the code duplication (additional instances of 
> rcu_read_unlock()) remains, I don't see any advantages.
>
> >   ipc/sem: rework task wakeups
> Acked

Thanks.

> >   ipc/sem: optimize perform_atomic_semop()
> I'm still thinking about it.
> Code duplication is evil, but perhaps it is the best solution.
>
> What I don't like is the hardcoded "< BITS_PER_LONG".
> At least:
> - (1 << sop->sem_num)
> + (1 << (sop->sem_num%BITS_PER_LONG))

Yeah, I'll send v3 for that.

> >   ipc/sem: explicitly inline check_restart
> Do we really need that? Isn't that the compiler's task?
> Especially since the compiler is already doing it correctly.

Yes, I mentioned in the changelog that the compiler does it and this is
merely explicit. That said I see no harm in it, I guess whatever akpm says.

> >   ipc/sem: use proper list api for pending_list wakeups
> Acked

Thanks,
Davidlohr