search for: get_pending

When get_pending detects the task has been marked to be killed we try to clean up the SIGKLL by doing a sigdelset and recalc_sigpending, but we still leave it in shared_pending. If the signal is being short circuit delivered there is no need to put in shared_pending so this adds a check in complete_signal. This pa...

The following patches made over Linus's tree fix the 2 bugs: 1. vhost worker task shows up as a process forked from the parent that did VHOST_SET_OWNER ioctl instead of a process under root/kthreadd. This was causing breaking scripts. 2. vhost_tasks didn't disable or add support for freeze requests. The following patches fix these issues by making the vhost_task task a thread under the

...is used here because the get_qlock() - * function below may not be a full memory barrier. - * - * *,x,y -> *,0,0 + * We are now waiting for the pending bit to get cleared. */ - while ((val = smp_load_acquire(&lock->val.counter)) - & _Q_LOCKED_PENDING_MASK) + // make a get_pending(lock, &val) helper + while ((val = smp_load_acquire(&lock->val.counter)) & _Q_PENDING_MASK) + // would longer body ease cacheline contention? + // would it be better to use monitor/mwait instead? + // (we can tolerate some delay because we aren't pending ...) arch_mutex_cpu...

2014-05-14 19:00+0200, Peter Zijlstra: > On Wed, May 14, 2014 at 06:51:24PM +0200, Radim Kr?m?? wrote: > > Ok. > > I've seen merit in pvqspinlock even with slightly slower first-waiter, > > so I would have happily sacrificed those horrible branches. > > (I prefer elegant to optimized code, but I can see why we want to be > > strictly better than ticketlock.)

2014-05-14 19:00+0200, Peter Zijlstra: > On Wed, May 14, 2014 at 06:51:24PM +0200, Radim Kr?m?? wrote: > > Ok. > > I've seen merit in pvqspinlock even with slightly slower first-waiter, > > so I would have happily sacrificed those horrible branches. > > (I prefer elegant to optimized code, but I can see why we want to be > > strictly better than ticketlock.)