Messages in this thread Patch in this message | | | Date | Mon, 11 Dec 2017 14:32:41 -0500 | From | Steven Rostedt <> | Subject | Re: [RFC][PATCH] ipc: mqueue: wq_add priority changed to dynamic priority |
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On Mon, 11 Dec 2017 17:12:05 +0000 Jonathan Haws <jhaws@sdl.usu.edu> wrote:
> Adding linux-rt-users group to thread. > ________________________________________ > From: Jonathan Haws <jhaws@sdl.usu.edu> > Sent: Monday, December 11, 2017 08:37 > To: mingo@kernel.org; viro@zeniv.linux.org.uk; arnd@arndb.de; akpm@linux-foundation.org; deepa.kernel@gmail.com > Cc: linux-kernel@vger.kernel.org; tglx@linutronix.de; bigeasy@linutronix.de; rostedt@goodmis.org; 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) <rostedt@goodmis.org>
-- Steve
> > Signed-off-by: Jonathan Haws <jhaws@sdl.usu.edu> > --- > 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 >
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