On Wed, Sep 04, 2019 at 09:24:18AM -0400, Joel Fernandes wrote: > On Wed, Sep 04, 2019 at 01:30:38PM +0200, Peter Zijlstra wrote: > > On Wed, Sep 04, 2019 at 06:16:16AM -0400, Steven Rostedt wrote: > > > On Mon, 2 Sep 2019 11:16:23 +0200 > > > Peter Zijlstra <[email protected]> wrote: > > > > > > > in sched_dl_period_handler(). And do: > > > > > > > > + preempt_disable(); > > > > max = (u64)READ_ONCE(sysctl_sched_dl_period_max) * > > > > NSEC_PER_USEC; > > > > min = (u64)READ_ONCE(sysctl_sched_dl_period_min) * > > > > NSEC_PER_USEC; > > > > + preempt_enable(); > > > > > > Hmm, I'm curious. Doesn't the preempt_disable/enable() also add > > > compiler barriers which would remove the need for the READ_ONCE()s here? > > > > They do add compiler barriers; but they do not avoid the compiler > > tearing stuff up. > > Neither does WRITE_ONCE() on some possibly buggy but currently circulating > compilers :(
Yes, I'm aware :/
