diff options
| author | Aaron Tomlin <atomlin@atomlin.com> | 2025-10-10 21:28:53 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-11-26 15:20:51 +0100 |
| commit | cd22926af45400093738c758b6749de8035ed5a8 (patch) | |
| tree | 12edfbf74edaf0886e7e14ffc39f6568a1c9aece /drivers/base | |
| parent | f10c23fa159c5481dfe0025e619dc5ef844f6ce1 (diff) | |
tick/nohz: Expose housekeeping CPUs in sysfs
Expose the current system-defined list of housekeeping CPUs in a new
sysfs file: /sys/devices/system/cpu/housekeeping.
This provides userspace performance tuning tools and resource managers
with a canonical, reliable method to accurately identify the cores
responsible for essential kernel maintenance workloads (RCU, timer
callbacks, and unbound workqueues). Currently, tooling must manually
calculate the housekeeping set by parsing complex kernel boot parameters
(like isolcpus= and nohz_full=) and system topology, which is prone to
error. This dedicated file simplifies the configuration of low-latency
workloads.
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Link: https://patch.msgid.link/20251011012853.7539-2-atomlin@atomlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/cpu.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index e3cb47eae982..c6c57b6f61c6 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -300,6 +300,19 @@ static ssize_t print_cpus_isolated(struct device *dev, } static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL); +static ssize_t housekeeping_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + const struct cpumask *hk_mask; + + hk_mask = housekeeping_cpumask(HK_TYPE_KERNEL_NOISE); + + if (housekeeping_enabled(HK_TYPE_KERNEL_NOISE)) + return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(hk_mask)); + return sysfs_emit(buf, "\n"); +} +static DEVICE_ATTR_RO(housekeeping); + #ifdef CONFIG_NO_HZ_FULL static ssize_t nohz_full_show(struct device *dev, struct device_attribute *attr, @@ -509,6 +522,7 @@ static struct attribute *cpu_root_attrs[] = { &dev_attr_offline.attr, &dev_attr_enabled.attr, &dev_attr_isolated.attr, + &dev_attr_housekeeping.attr, #ifdef CONFIG_NO_HZ_FULL &dev_attr_nohz_full.attr, #endif |