On 3/1/16 2:51 PM, tip-bot for Thomas Gleixner wrote: > Commit-ID: 090e77c391dd983c8945b8e2e16d09f378d2e334 > Gitweb: http://git.kernel.org/tip/090e77c391dd983c8945b8e2e16d09f378d2e334 > Author: Thomas Gleixner <t...@linutronix.de> > AuthorDate: Fri, 26 Feb 2016 18:43:23 +0000 > Committer: Thomas Gleixner <t...@linutronix.de> > CommitDate: Tue, 1 Mar 2016 20:36:53 +0100 > > cpu/hotplug: Restructure FROZEN state handling > > There are only a few callbacks which really care about FROZEN > vs. !FROZEN. No need to have extra states for this. > > Publish the frozen state in an extra variable which is updated under > the hotplug lock and let the users interested deal with it w/o > imposing that extra state checks on everyone. > > Signed-off-by: Thomas Gleixner <t...@linutronix.de> > Cc: linux-a...@vger.kernel.org > Cc: Rik van Riel <r...@redhat.com> > Cc: Rafael Wysocki <rafael.j.wyso...@intel.com> > Cc: "Srivatsa S. Bhat" <sriva...@mit.edu> > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Arjan van de Ven <ar...@linux.intel.com> > Cc: Sebastian Siewior <bige...@linutronix.de> > Cc: Rusty Russell <ru...@rustcorp.com.au> > Cc: Steven Rostedt <rost...@goodmis.org> > Cc: Oleg Nesterov <o...@redhat.com> > Cc: Tejun Heo <t...@kernel.org> > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: Paul McKenney <paul...@linux.vnet.ibm.com> > Cc: Linus Torvalds <torva...@linux-foundation.org> > Cc: Paul Turner <p...@google.com> > Link: http://lkml.kernel.org/r/20160226182340.334912...@linutronix.de > Signed-off-by: Thomas Gleixner <t...@linutronix.de> > --- > include/linux/cpu.h | 2 ++ > kernel/cpu.c | 69 > ++++++++++++++++++++++------------------------------- > 2 files changed, 31 insertions(+), 40 deletions(-) > > diff --git a/include/linux/cpu.h b/include/linux/cpu.h > index d2ca8c3..f2fb549 100644 > --- a/include/linux/cpu.h > +++ b/include/linux/cpu.h > @@ -118,6 +118,7 @@ enum { > > > #ifdef CONFIG_SMP > +extern bool cpuhp_tasks_frozen; > /* Need to know about CPUs going up/down? */ > #if defined(CONFIG_HOTPLUG_CPU) || !defined(MODULE) > #define cpu_notifier(fn, pri) { \ > @@ -177,6 +178,7 @@ extern void cpu_maps_update_done(void); > #define cpu_notifier_register_done cpu_maps_update_done > > #else /* CONFIG_SMP */ > +#define cpuhp_tasks_frozen 0 > > #define cpu_notifier(fn, pri) do { (void)(fn); } while (0) > #define __cpu_notifier(fn, pri) do { (void)(fn); } while (0) > diff --git a/kernel/cpu.c b/kernel/cpu.c > index 5b9d396..41a6cb8 100644 > --- a/kernel/cpu.c > +++ b/kernel/cpu.c > @@ -29,6 +29,8 @@ > #ifdef CONFIG_SMP > /* Serializes the updates to cpu_online_mask, cpu_present_mask */ > static DEFINE_MUTEX(cpu_add_remove_lock); > +bool cpuhp_tasks_frozen; > +EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); >
One small nitpick though: we don't need to export this symbol yet; it can be deferred until the callbacks that need it are actually modified to use this value (presumably in a later patchset). Regards, Srivatsa S. Bhat