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nohz_full: Add full-system-idle arguments to API

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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>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
[ paulmck: Use true and false for boolean constants per Lai Jiangshan. ]
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
Paul E. McKenney 2013-06-21 15:39:06 -07:00
parent d4bd54fbac
commit 217af2a2ff
1 changed files with 18 additions and 7 deletions
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25
kernel/rcutree.c
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@ -246,7 +246,10 @@ 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 *rsp, bool *isidle,
unsigned long *maxj),
bool *isidle, unsigned long *maxj);
static void force_quiescent_state(struct rcu_state *rsp);
static int rcu_pending(int cpu);
@ -727,7 +730,8 @@ 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;
@ -739,7 +743,8 @@ 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;
@ -1361,16 +1366,19 @@ 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 = false;
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) {
@ -2069,7 +2077,10 @@ 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 *rsp, bool *isidle,
unsigned long *maxj),
bool *isidle, unsigned long *maxj)
{
unsigned long bit;
int cpu;
@ -2093,7 +2104,7 @@ 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) {