On Thu, May 29, 2014 at 11:24:15AM -0500, Christoph Lameter wrote: > On Thu, 29 May 2014, Frederic Weisbecker wrote: > > > > Well yes and I am tying directly into that scheme there in cpu.c to > > > display the active vmstat threads in sysfs. so its the same. > > > > I don't think so. Or is there something in vmstat that cpumask_var_t > > definition depends upon? > > This patch definitely ties the vmstat cpumask into the scheme in cpu.c > > > > I would like to have some way to display the activities on cpus in /sysfs > > > like I have done here with the active vmstat workers. > > > > > > What I think we need is display cpumasks for > > > > > > 1. Cpus where the tick is currently off > > > 2. Cpus that have dynticks enabled. > > > 3. Cpus that are idle > > > > You should find all that in /proc/timer_list > > True. I could actually drop the vmstat cpumask support. > > > Now for CPUs that have full dynticks enabled, we probably need something > > in sysfs. We could dump the nohz cpumask somewhere. For now you can only grep > > the dmesg > > There is a nohz mode in /proc/timer_list right? > > > > 4. Cpus that are used for RCU. > > > > So, you mean those that aren't in extended grace period (between rcu_user_enter()/exit > > or rcu_idle_enter/exit)? > > No I mean cpus that have their RCU processing directed to another > processor. Ah, that is easier! In kernel/rcu/tree_plugin.c under #ifdef CONFIG_RCU_NOCB_CPU: cpumask_var_t get_rcu_nocb_mask(void) { return rcu_nocb_mask; } In include/linux/rcupdate.h: #if defined(CONFIG_TINY_RCU) || !defined(CONFIG_RCU_NOCB_CPU) static inline cpumask_var_t get_rcu_nocb_mask(void) { return NULL; } #else cpumask_var_t get_rcu_nocb_mask(void); #endif Then display the mask however you prefer. Modifying the mask is a very bad idea, and will void your warranty, etc., etc. Thanx, Paul -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>