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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
Download Patch File Download Diff File Expand all files Collapse all files

32
kernel/rcuclassic.c
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@@ -63,14 +63,14 @@ static struct rcu_ctrlblk rcu_ctrlblk = {
.completed = -300,
.pending = -300,
.lock = __SPIN_LOCK_UNLOCKED(&rcu_ctrlblk.lock),
.cpumask = CPU_MASK_NONE,
.cpumask = CPU_BITS_NONE,
};
static struct rcu_ctrlblk rcu_bh_ctrlblk = {
.cur = -300,
.completed = -300,
.pending = -300,
.lock = __SPIN_LOCK_UNLOCKED(&rcu_bh_ctrlblk.lock),
.cpumask = CPU_MASK_NONE,
.cpumask = CPU_BITS_NONE,
};
DEFINE_PER_CPU(struct rcu_data, rcu_data) = { 0L };
@@ -85,7 +85,6 @@ static void force_quiescent_state(struct rcu_data *rdp,
struct rcu_ctrlblk *rcp)
{
int cpu;
cpumask_t cpumask;
unsigned long flags;
set_need_resched();
@@ -96,10 +95,10 @@ static void force_quiescent_state(struct rcu_data *rdp,
* Don't send IPI to itself. With irqs disabled,
* rdp->cpu is the current cpu.
*
* cpu_online_map is updated by the _cpu_down()
* cpu_online_mask is updated by the _cpu_down()
* using __stop_machine(). Since we're in irqs disabled
* section, __stop_machine() is not exectuting, hence
* the cpu_online_map is stable.
* the cpu_online_mask is stable.
*
* However, a cpu might have been offlined _just_ before
* we disabled irqs while entering here.
@@ -107,13 +106,14 @@ static void force_quiescent_state(struct rcu_data *rdp,
* notification, leading to the offlined cpu's bit
* being set in the rcp->cpumask.
*
* Hence cpumask = (rcp->cpumask & cpu_online_map) to prevent
* Hence cpumask = (rcp->cpumask & cpu_online_mask) to prevent
* sending smp_reschedule() to an offlined CPU.
*/
cpus_and(cpumask, rcp->cpumask, cpu_online_map);
cpu_clear(rdp->cpu, cpumask);
for_each_cpu_mask_nr(cpu, cpumask)
smp_send_reschedule(cpu);
for_each_cpu_and(cpu,
to_cpumask(rcp->cpumask), cpu_online_mask) {
if (cpu != rdp->cpu)
smp_send_reschedule(cpu);
}
}
spin_unlock_irqrestore(&rcp->lock, flags);
}
@@ -193,7 +193,7 @@ static void print_other_cpu_stall(struct rcu_ctrlblk *rcp)
printk(KERN_ERR "INFO: RCU detected CPU stalls:");
for_each_possible_cpu(cpu) {
if (cpu_isset(cpu, rcp->cpumask))
if (cpumask_test_cpu(cpu, to_cpumask(rcp->cpumask)))
printk(" %d", cpu);
}
printk(" (detected by %d, t=%ld jiffies)\n",
@@ -221,7 +221,8 @@ static void check_cpu_stall(struct rcu_ctrlblk *rcp)
long delta;
delta = jiffies - rcp->jiffies_stall;
if (cpu_isset(smp_processor_id(), rcp->cpumask) && delta >= 0) {
if (cpumask_test_cpu(smp_processor_id(), to_cpumask(rcp->cpumask)) &&
delta >= 0) {
/* We haven't checked in, so go dump stack. */
print_cpu_stall(rcp);
@@ -393,7 +394,8 @@ static void rcu_start_batch(struct rcu_ctrlblk *rcp)
* unnecessarily.
*/
smp_mb();
cpus_andnot(rcp->cpumask, cpu_online_map, nohz_cpu_mask);
cpumask_andnot(to_cpumask(rcp->cpumask),
cpu_online_mask, &nohz_cpu_mask);
rcp->signaled = 0;
}
@@ -406,8 +408,8 @@ static void rcu_start_batch(struct rcu_ctrlblk *rcp)
*/
static void cpu_quiet(int cpu, struct rcu_ctrlblk *rcp)
{
cpu_clear(cpu, rcp->cpumask);
if (cpus_empty(rcp->cpumask)) {
cpumask_clear_cpu(cpu, to_cpumask(rcp->cpumask));
if (cpumask_empty(to_cpumask(rcp->cpumask))) {
/* batch completed ! */
rcp->completed = rcp->cur;
rcu_start_batch(rcp);