redonkable/alistair23-linux
redonkable/alistair23-linux
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Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  kernel/softirq.c: fix sparse warning
  rcu: Make hierarchical RCU less IPI-happy
This commit is contained in:
Linus Torvalds 2009-04-16 17:56:39 -07:00
parent 20d9207849 79d381c9f2
commit 4d831f53dd
4 changed files with 12 additions and 28 deletions
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3
include/linux/rcutree.h
View file

@ -161,9 +161,8 @@ struct rcu_data {
unsigned long offline_fqs; /* Kicked due to being offline. */
unsigned long resched_ipi; /* Sent a resched IPI. */
/* 5) state to allow this CPU to force_quiescent_state on others */
/* 5) For future __rcu_pending statistics. */
long n_rcu_pending; /* rcu_pending() calls since boot. */
long n_rcu_pending_force_qs; /* when to force quiescent states. */
int cpu;
};

19
kernel/rcutree.c
View file

@ -530,8 +530,6 @@ static void note_new_gpnum(struct rcu_state *rsp, struct rcu_data *rdp)
rdp->qs_pending = 1;
rdp->passed_quiesc = 0;
rdp->gpnum = rsp->gpnum;
rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
RCU_JIFFIES_TILL_FORCE_QS;
}
/*
@ -578,8 +576,6 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
rsp->gpnum++;
rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
RCU_JIFFIES_TILL_FORCE_QS;
record_gp_stall_check_time(rsp);
dyntick_record_completed(rsp, rsp->completed - 1);
note_new_gpnum(rsp, rdp);
@ -1055,7 +1051,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
{
unsigned long flags;
long lastcomp;
struct rcu_data *rdp = rsp->rda[smp_processor_id()];
struct rcu_node *rnp = rcu_get_root(rsp);
u8 signaled;
@ -1066,16 +1061,13 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
return; /* Someone else is already on the job. */
}
if (relaxed &&
(long)(rsp->jiffies_force_qs - jiffies) >= 0 &&
(rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) >= 0)
(long)(rsp->jiffies_force_qs - jiffies) >= 0)
goto unlock_ret; /* no emergency and done recently. */
rsp->n_force_qs++;
spin_lock(&rnp->lock);
lastcomp = rsp->completed;
signaled = rsp->signaled;
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
RCU_JIFFIES_TILL_FORCE_QS;
if (lastcomp == rsp->gpnum) {
rsp->n_force_qs_ngp++;
spin_unlock(&rnp->lock);
@ -1144,8 +1136,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
* If an RCU GP has gone long enough, go check for dyntick
* idle CPUs and, if needed, send resched IPIs.
*/
if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
(rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0)
if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)
force_quiescent_state(rsp, 1);
/*
@ -1230,8 +1221,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
if (unlikely(++rdp->qlen > qhimark)) {
rdp->blimit = LONG_MAX;
force_quiescent_state(rsp, 0);
} else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
(rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0)
} else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)
force_quiescent_state(rsp, 1);
local_irq_restore(flags);
}
@ -1290,8 +1280,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
/* Has an RCU GP gone long enough to send resched IPIs &c? */
if (ACCESS_ONCE(rsp->completed) != ACCESS_ONCE(rsp->gpnum) &&
((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
(rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0))
((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0))
return 1;
/* nothing to do */

14
kernel/rcutree_trace.c
View file

@ -49,14 +49,12 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
{
if (!rdp->beenonline)
return;
seq_printf(m, "%3d%cc=%ld g=%ld pq=%d pqc=%ld qp=%d rpfq=%ld rp=%x",
seq_printf(m, "%3d%cc=%ld g=%ld pq=%d pqc=%ld qp=%d",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? '!' : ' ',
rdp->completed, rdp->gpnum,
rdp->passed_quiesc, rdp->passed_quiesc_completed,
rdp->qs_pending,
rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending,
(int)(rdp->n_rcu_pending & 0xffff));
rdp->qs_pending);
#ifdef CONFIG_NO_HZ
seq_printf(m, " dt=%d/%d dn=%d df=%lu",
rdp->dynticks->dynticks,
@ -102,14 +100,12 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
{
if (!rdp->beenonline)
return;
seq_printf(m, "%d,%s,%ld,%ld,%d,%ld,%d,%ld,%ld",
seq_printf(m, "%d,%s,%ld,%ld,%d,%ld,%d",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? "\"Y\"" : "\"N\"",
rdp->completed, rdp->gpnum,
rdp->passed_quiesc, rdp->passed_quiesc_completed,
rdp->qs_pending,
rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending,
rdp->n_rcu_pending);
rdp->qs_pending);
#ifdef CONFIG_NO_HZ
seq_printf(m, ",%d,%d,%d,%lu",
rdp->dynticks->dynticks,
@ -123,7 +119,7 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
static int show_rcudata_csv(struct seq_file *m, void *unused)
{
seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",\"rpfq\",\"rp\",");
seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
#ifdef CONFIG_NO_HZ
seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\",");
#endif /* #ifdef CONFIG_NO_HZ */

4
kernel/softirq.c
View file

@ -472,9 +472,9 @@ void tasklet_kill(struct tasklet_struct *t)
printk("Attempt to kill tasklet from interrupt\n");
while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
do
do {
yield();
while (test_bit(TASKLET_STATE_SCHED, &t->state));
} while (test_bit(TASKLET_STATE_SCHED, &t->state));
}
tasklet_unlock_wait(t);
clear_bit(TASKLET_STATE_SCHED, &t->state);