nohz_full: Add full-system-idle arguments to API

This commit adds an isidle and jiffies argument to force_qs_rnp(),
dyntick_save_progress_counter(), and rcu_implicit_dynticks_qs() to enable
RCU's force-quiescent-state process to check for full-system idle.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index c1f7cf89349fcb49534101e588f27058bc31e9f0..725524e7204ba0043a0c0f7aa3203eaea1ea6caf 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -231,7 +231,9 @@ module_param(jiffies_till_next_fqs, ulong, 0644);
 
 static void rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
                                  struct rcu_data *rdp);
-static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *));
+static void force_qs_rnp(struct rcu_state *rsp,
+                        int (*f)(struct rcu_data *, bool *, unsigned long *),
+                        bool *isidle, unsigned long *maxj);
 static void force_quiescent_state(struct rcu_state *rsp);
 static int rcu_pending(int cpu);
 
@@ -712,7 +714,8 @@ static int rcu_is_cpu_rrupt_from_idle(void)
  * credit them with an implicit quiescent state.  Return 1 if this CPU
  * is in dynticks idle mode, which is an extended quiescent state.
  */
-static int dyntick_save_progress_counter(struct rcu_data *rdp)
+static int dyntick_save_progress_counter(struct rcu_data *rdp,
+                                        bool *isidle, unsigned long *maxj)
 {
        rdp->dynticks_snap = atomic_add_return(0, &rdp->dynticks->dynticks);
        return (rdp->dynticks_snap & 0x1) == 0;
@@ -724,7 +727,8 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp)
  * idle state since the last call to dyntick_save_progress_counter()
  * for this same CPU, or by virtue of having been offline.
  */
-static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
+static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
+                                   bool *isidle, unsigned long *maxj)
 {
        unsigned int curr;
        unsigned int snap;
@@ -1345,16 +1349,19 @@ static int rcu_gp_init(struct rcu_state *rsp)
 int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in)
 {
        int fqs_state = fqs_state_in;
+       bool isidle = 0;
+       unsigned long maxj;
        struct rcu_node *rnp = rcu_get_root(rsp);
 
        rsp->n_force_qs++;
        if (fqs_state == RCU_SAVE_DYNTICK) {
                /* Collect dyntick-idle snapshots. */
-               force_qs_rnp(rsp, dyntick_save_progress_counter);
+               force_qs_rnp(rsp, dyntick_save_progress_counter,
+                            &isidle, &maxj);
                fqs_state = RCU_FORCE_QS;
        } else {
                /* Handle dyntick-idle and offline CPUs. */
-               force_qs_rnp(rsp, rcu_implicit_dynticks_qs);
+               force_qs_rnp(rsp, rcu_implicit_dynticks_qs, &isidle, &maxj);
        }
        /* Clear flag to prevent immediate re-entry. */
        if (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) {
@@ -2055,7 +2062,9 @@ void rcu_check_callbacks(int cpu, int user)
  *
  * The caller must have suppressed start of new grace periods.
  */
-static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *))
+static void force_qs_rnp(struct rcu_state *rsp,
+                        int (*f)(struct rcu_data *, bool *, unsigned long *),
+                        bool *isidle, unsigned long *maxj)
 {
        unsigned long bit;
        int cpu;
@@ -2079,7 +2088,7 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *))
                bit = 1;
                for (; cpu <= rnp->grphi; cpu++, bit <<= 1) {
                        if ((rnp->qsmask & bit) != 0 &&
-                           f(per_cpu_ptr(rsp->rda, cpu)))
+                           f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj))
                                mask |= bit;
                }
                if (mask != 0) {