Improve documentation and logging for banned cpus

This patch have no functional modification. Just improve the doc and log
for isolcpu, nohz_full and numa node banning cpus, for providing more
info for users.

Signed-off-by: Tao Liu <ltao@redhat.com>
This commit is contained in:
Tao Liu 2022-07-13 17:11:40 +08:00
parent d558be31ab
commit cfb15f0bb9
3 changed files with 9 additions and 5 deletions

View File

@ -159,14 +159,14 @@ static void setup_banned_cpus(void)
cpus_or(banned_cpus, nohz_full, isolated_cpus);
cpumask_scnprintf(buffer, 4096, isolated_cpus);
log(TO_CONSOLE, LOG_INFO, "Isolated CPUs: %s\n", buffer);
log(TO_CONSOLE, LOG_INFO, "Prevent irq assignment to these isolated CPUs: %s\n", buffer);
cpumask_scnprintf(buffer, 4096, nohz_full);
log(TO_CONSOLE, LOG_INFO, "Adaptive-ticks CPUs: %s\n", buffer);
log(TO_CONSOLE, LOG_INFO, "Prevent irq assignment to these adaptive-ticks CPUs: %s\n", buffer);
out:
#ifdef HAVE_THERMAL
cpus_or(banned_cpus, banned_cpus, thermal_banned_cpus);
cpumask_scnprintf(buffer, 4096, thermal_banned_cpus);
log(TO_CONSOLE, LOG_INFO, "Thermal-banned CPUs: %s\n", buffer);
log(TO_CONSOLE, LOG_INFO, "Prevent irq assignment to these thermal-banned CPUs: %s\n", buffer);
#endif
cpumask_scnprintf(buffer, 4096, banned_cpus);
log(TO_CONSOLE, LOG_INFO, "Banned CPUs: %s\n", buffer);

View File

@ -167,7 +167,7 @@ Same as --debug.
.B IRQBALANCE_BANNED_CPUS
Provides a mask of CPUs which irqbalance should ignore and never assign interrupts to.
If not specified, irqbalance use mask of isolated and adaptive-ticks CPUs on the
system as the default value.
system as the default value. The "isolcpus=" boot parameter specifies the isolated CPUs. The "nohz_full=" boot parameter specifies the adaptive-ticks CPUs. By default, no CPU will be an isolated or adaptive-ticks CPU.
This is a hexmask without the leading 0x. On systems with large numbers of
processors, each group of eight hex digits is separated by a comma ,. i.e.
export IRQBALANCE_BANNED_CPUS=fc0 would prevent irqbalance from assigning irqs

View File

@ -135,8 +135,12 @@ static void place_irq_in_node(struct irq_info *info, void *data __attribute__((u
* Need to make sure this node is elligible for migration
* given the banned cpu list
*/
if (!cpus_intersects(irq_numa_node(info)->mask, unbanned_cpus))
if (!cpus_intersects(irq_numa_node(info)->mask, unbanned_cpus)) {
log(TO_CONSOLE, LOG_WARNING, "There is no suitable CPU in node:%d.\n", irq_numa_node(info)->number);
log(TO_CONSOLE, LOG_WARNING, "Irqbalance dispatch irq:%d to other node.\n", info->irq);
goto find_placement;
}
/*
* This irq belongs to a device with a preferred numa node
* put it on that node