On Mon, 22 May 2017 17:00:36 -0700 "Paul E. McKenney" <paul...@linux.vnet.ibm.com> wrote:
> > > > Hmmm... The goal is to make sure that any task that was preempted > > or running at a given point in time passes through a voluntary > > context switch (or userspace execution, or, ...). > > > > What is the simplest way to get this job done? To Ingo's point, I > > bet that there is a simpler way than the current TASKS_RCU > > implementation. > > > > Ingo, if I make it fit into 100 lines of code, would you be OK with > > it? I probably need a one-line hook at task-creation time and > > another at task-exit time, if that makes a difference. > > And please see below for such a patch, which does add (just barely) > fewer than 100 lines net. > > Unfortunately, it does not work, as I should have known ahead of time > from the dyntick-idle experience. Not all context switches go through > context_switch(). :-/ Wait. What context switch doesn't go through a context switch? Or do you mean a user/kernel context switch? -- Steve > > I believe this is fixable, more or less like dyntick-idle's > half-interrupts were fixable, but it will likely be a few days. Not > clear whether the result will be simpler than current TASKS_RCU, but > there is only one way to find out. ;-) >
