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cpumask: convert RCU implementations

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Impact: use new cpumask API.

rcu_ctrlblk contains a cpumask, and it's highly optimized so I don't want
a cpumask_var_t (ie. a pointer) for the CONFIG_CPUMASK_OFFSTACK case.  It
could use a dangling bitmap, and be allocated in __rcu_init to save memory,
but for the moment we use a bitmap.

(Eventually 'struct cpumask' will be undefined for CONFIG_CPUMASK_OFFSTACK,
so we use a bitmap here to show we really mean it).

We remove on-stack cpumasks, using cpumask_var_t for
rcu_torture_shuffle_tasks() and for_each_cpu_and in force_quiescent_state().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2009-01-01 10:12:26 +10:30
parent d036e67b40
commit bd232f97b3
4 changed files with 44 additions and 38 deletions
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19
kernel/rcupreempt.c
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@ -164,7 +164,8 @@ static char *rcu_try_flip_state_names[] =
{ "idle", "waitack", "waitzero", "waitmb" };
#endif /* #ifdef CONFIG_RCU_TRACE */
static cpumask_t rcu_cpu_online_map __read_mostly = CPU_MASK_NONE;
static DECLARE_BITMAP(rcu_cpu_online_map, NR_CPUS) __read_mostly
= CPU_BITS_NONE;
/*
* Enum and per-CPU flag to determine when each CPU has seen
@ -758,7 +759,7 @@ rcu_try_flip_idle(void)
/* Now ask each CPU for acknowledgement of the flip. */
for_each_cpu_mask_nr(cpu, rcu_cpu_online_map) {
for_each_cpu(cpu, to_cpumask(rcu_cpu_online_map)) {
per_cpu(rcu_flip_flag, cpu) = rcu_flipped;
dyntick_save_progress_counter(cpu);
}
@ -776,7 +777,7 @@ rcu_try_flip_waitack(void)
int cpu;
RCU_TRACE_ME(rcupreempt_trace_try_flip_a1);
for_each_cpu_mask_nr(cpu, rcu_cpu_online_map)
for_each_cpu(cpu, to_cpumask(rcu_cpu_online_map))
if (rcu_try_flip_waitack_needed(cpu) &&
per_cpu(rcu_flip_flag, cpu) != rcu_flip_seen) {
RCU_TRACE_ME(rcupreempt_trace_try_flip_ae1);
@ -808,7 +809,7 @@ rcu_try_flip_waitzero(void)
/* Check to see if the sum of the "last" counters is zero. */
RCU_TRACE_ME(rcupreempt_trace_try_flip_z1);
for_each_cpu_mask_nr(cpu, rcu_cpu_online_map)
for_each_cpu(cpu, to_cpumask(rcu_cpu_online_map))
sum += RCU_DATA_CPU(cpu)->rcu_flipctr[lastidx];
if (sum != 0) {
RCU_TRACE_ME(rcupreempt_trace_try_flip_ze1);
@ -823,7 +824,7 @@ rcu_try_flip_waitzero(void)
smp_mb(); /* ^^^^^^^^^^^^ */
/* Call for a memory barrier from each CPU. */
for_each_cpu_mask_nr(cpu, rcu_cpu_online_map) {
for_each_cpu(cpu, to_cpumask(rcu_cpu_online_map)) {
per_cpu(rcu_mb_flag, cpu) = rcu_mb_needed;
dyntick_save_progress_counter(cpu);
}
@ -843,7 +844,7 @@ rcu_try_flip_waitmb(void)
int cpu;
RCU_TRACE_ME(rcupreempt_trace_try_flip_m1);
for_each_cpu_mask_nr(cpu, rcu_cpu_online_map)
for_each_cpu(cpu, to_cpumask(rcu_cpu_online_map))
if (rcu_try_flip_waitmb_needed(cpu) &&
per_cpu(rcu_mb_flag, cpu) != rcu_mb_done) {
RCU_TRACE_ME(rcupreempt_trace_try_flip_me1);
@ -1032,7 +1033,7 @@ void rcu_offline_cpu(int cpu)
RCU_DATA_CPU(cpu)->rcu_flipctr[0] = 0;
RCU_DATA_CPU(cpu)->rcu_flipctr[1] = 0;
cpu_clear(cpu, rcu_cpu_online_map);
cpumask_clear_cpu(cpu, to_cpumask(rcu_cpu_online_map));
spin_unlock_irqrestore(&rcu_ctrlblk.fliplock, flags);
@ -1072,7 +1073,7 @@ void __cpuinit rcu_online_cpu(int cpu)
struct rcu_data *rdp;
spin_lock_irqsave(&rcu_ctrlblk.fliplock, flags);
cpu_set(cpu, rcu_cpu_online_map);
cpumask_set_cpu(cpu, to_cpumask(rcu_cpu_online_map));
spin_unlock_irqrestore(&rcu_ctrlblk.fliplock, flags);
/*
@ -1430,7 +1431,7 @@ void __init __rcu_init(void)
* We don't need protection against CPU-Hotplug here
* since
* a) If a CPU comes online while we are iterating over the
* cpu_online_map below, we would only end up making a
* cpu_online_mask below, we would only end up making a
* duplicate call to rcu_online_cpu() which sets the corresponding
* CPU's mask in the rcu_cpu_online_map.
*