diff options
| author | Aaron Tomlin <atomlin@atomlin.com> | 2025-10-10 21:18:30 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-11-26 15:20:49 +0100 |
| commit | f10c23fa159c5481dfe0025e619dc5ef844f6ce1 (patch) | |
| tree | fa406881c203ff437e9d946f2e50e85375fb78e8 /drivers/base | |
| parent | 76987bac71d5349a62f312ca1cd92de73778a652 (diff) | |
tick/nohz: avoid showing '(null)' if nohz_full= not set
In the context of CONFIG_NO_HZ_FULL=y, tick_nohz_full_mask (of type
cpumask_var_t) is initialised to 0. Memory is only allocated to the cpumask
data structure, in tick_nohz_full_setup(), when Linux kernel boot-time
parameter "nohz_full=" is correctly specified (see housekeeping_setup()).
If "nohz_full=" is not set and an attempt is made to read
/sys/devices/system/cpu/nohz_full, '(null)' can be displayed:
❯ cat /sys/devices/system/cpu/nohz_full
(null)
This patch changes the output to print a newline (or 0x0A) instead of
'(null)', making it consistent with print_cpus_isolated() behaviour.
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Link: https://patch.msgid.link/20251011011830.6670-3-atomlin@atomlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/cpu.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index c792ec66462d..e3cb47eae982 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -305,7 +305,10 @@ static ssize_t nohz_full_show(struct device *dev, struct device_attribute *attr, char *buf) { - return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask)); + if (cpumask_available(tick_nohz_full_mask)) + return sysfs_emit(buf, "%*pbl\n", + cpumask_pr_args(tick_nohz_full_mask)); + return sysfs_emit(buf, "\n"); } static DEVICE_ATTR_RO(nohz_full); #endif |