On Mon, 11 Dec 2017 17:12:05 +0000 Jonathan Haws <[email protected]> wrote:
> Adding linux-rt-users group to thread. > ________________________________________ > From: Jonathan Haws <[email protected]> > Sent: Monday, December 11, 2017 08:37 > To: [email protected]; [email protected]; [email protected]; > [email protected]; [email protected] > Cc: [email protected]; [email protected]; [email protected]; > [email protected]; Jonathan Haws > Subject: [RFC][PATCH] ipc: mqueue: wq_add priority changed to dynamic priority > > Previous behavior added tasks to the work queue using the static_prio value > instead of the dynamic priority value in prio. This caused RT tasks to be > added to the work queue in a FIFO manner rather than by priority. Normal > tasks were handled by priority. > > This fix utilizes the dynamic priority of the task to ensure that both RT > and normal tasks are added to the work queue in priority order. Utilizing > the dynamic priority (prio) rather than the base priority (normal_prio) was > chosen to ensure that if a task had a boosted priority when it was added to > the work queue, it would be woken sooner to to ensure that it releases any > other locks it may be holding in a more timely manner. It is understood that > the task could have a lower priority when it wakes than when it was added to > the queue in this (unlikely) case. Probably a better subject would be: ipc: mqueue: Have RT tasks queue in by priority in wq_add() Other than that (and that this doesn't handle DL tasks), Reviewed-by: Steven Rostedt (VMware) <[email protected]> -- Steve > > Signed-off-by: Jonathan Haws <[email protected]> > --- > ipc/mqueue.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/ipc/mqueue.c b/ipc/mqueue.c > index 9649ecd..cb96db9 100644 > --- a/ipc/mqueue.c > +++ b/ipc/mqueue.c > @@ -546,7 +546,7 @@ static void wq_add(struct mqueue_inode_info *info, int sr, > ewp->task = current; > > list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { > - if (walk->task->static_prio <= current->static_prio) { > + if (walk->task->prio <= current->prio) { > list_add_tail(&ewp->list, &walk->list); > return; > } > -- > 2.7.4 >
