ledtrig-cpu: Limit to 8 CPUs

Some machines have thousands of CPUs... and trigger mechanisms was not
really meant for thousands of triggers. I doubt anyone uses this
trigger on many-CPU machine; but if they do, they'll need to do it
properly.

Signed-off-by: Pavel Machek <pavel@ucw.cz>
This commit is contained in:
Pavel Machek 2020-09-19 11:34:58 +02:00
parent 364682d1bc
commit abcc131292

View File

@ -2,14 +2,18 @@
/*
* ledtrig-cpu.c - LED trigger based on CPU activity
*
* This LED trigger will be registered for each possible CPU and named as
* cpu0, cpu1, cpu2, cpu3, etc.
* This LED trigger will be registered for first 8 CPUs and named
* as cpu0..cpu7. There's additional trigger called cpu that
* is on when any CPU is active.
*
* If you want support for arbitrary number of CPUs, make it one trigger,
* with additional sysfs file selecting which CPU to watch.
*
* It can be bound to any LED just like other triggers using either a
* board file or via sysfs interface.
*
* An API named ledtrig_cpu is exported for any user, who want to add CPU
* activity indication in their code
* activity indication in their code.
*
* Copyright 2011 Linus Walleij <linus.walleij@linaro.org>
* Copyright 2011 - 2012 Bryan Wu <bryan.wu@canonical.com>
@ -145,6 +149,9 @@ static int __init ledtrig_cpu_init(void)
for_each_possible_cpu(cpu) {
struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
if (cpu >= 8)
continue;
snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);
led_trigger_register_simple(trig->name, &trig->_trig);