diff options
| author | Eric Dumazet <edumazet@google.com> | 2018-06-20 08:03:32 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-06-22 14:22:58 +0200 |
| commit | 74bdf7815dfb3805a37b0bba615814063a227bf5 (patch) | |
| tree | 7057de945fe8629787d7f7767ff11c905157c5af /kernel | |
| parent | 0a13ec0bbc42bddf90ab6a444df8aaa67c148b16 (diff) | |
genirq: Speedup show_interrupts()
Since commit 425a5072dcd1 ("genirq: Free irq_desc with rcu"),
show_interrupts() can be switched to rcu locking, which removes possible
contention on sparse_irq_lock.
The per_cpu count scan and print can be done without holding desc spinlock.
And there is no need to call kstat_irqs_cpu() and abuse irq_to_desc() while
holding rcu read lock, since desc and desc->kstat_irqs wont disappear or
change.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Link: https://lkml.kernel.org/r/20180620150332.163320-1-edumazet@google.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/irq/proc.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 37eda10f5c36..da9addb8d655 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -475,22 +475,24 @@ int show_interrupts(struct seq_file *p, void *v) seq_putc(p, '\n'); } - irq_lock_sparse(); + rcu_read_lock(); desc = irq_to_desc(i); if (!desc) goto outsparse; - raw_spin_lock_irqsave(&desc->lock, flags); - for_each_online_cpu(j) - any_count |= kstat_irqs_cpu(i, j); - action = desc->action; - if ((!action || irq_desc_is_chained(desc)) && !any_count) - goto out; + if (desc->kstat_irqs) + for_each_online_cpu(j) + any_count |= *per_cpu_ptr(desc->kstat_irqs, j); + + if ((!desc->action || irq_desc_is_chained(desc)) && !any_count) + goto outsparse; seq_printf(p, "%*d: ", prec, i); for_each_online_cpu(j) - seq_printf(p, "%10u ", kstat_irqs_cpu(i, j)); + seq_printf(p, "%10u ", desc->kstat_irqs ? + *per_cpu_ptr(desc->kstat_irqs, j) : 0); + raw_spin_lock_irqsave(&desc->lock, flags); if (desc->irq_data.chip) { if (desc->irq_data.chip->irq_print_chip) desc->irq_data.chip->irq_print_chip(&desc->irq_data, p); @@ -511,6 +513,7 @@ int show_interrupts(struct seq_file *p, void *v) if (desc->name) seq_printf(p, "-%-8s", desc->name); + action = desc->action; if (action) { seq_printf(p, " %s", action->name); while ((action = action->next) != NULL) @@ -518,10 +521,9 @@ int show_interrupts(struct seq_file *p, void *v) } seq_putc(p, '\n'); -out: raw_spin_unlock_irqrestore(&desc->lock, flags); outsparse: - irq_unlock_sparse(); + rcu_read_unlock(); return 0; } #endif |