From 4702f4eceb639b6af199151e352e570943619d98 Mon Sep 17 00:00:00 2001 From: Thomas Weißschuh Date: Mon, 10 Nov 2025 10:38:53 +0100 Subject: hrtimer: Store time as ktime_t in restart block MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The hrtimer core uses ktime_t to represent times, use that also for the restart block. CPU timers internally use nanoseconds instead of ktime_t but use the same restart block, so use the correct accessors for those. Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20251110-restart-block-expiration-v1-3-5d39cc93df4f@linutronix.de --- include/linux/restart_block.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h index 7e50bbc94e47..36ddfa1ec301 100644 --- a/include/linux/restart_block.h +++ b/include/linux/restart_block.h @@ -43,7 +43,7 @@ struct restart_block { struct __kernel_timespec __user *rmtp; struct old_timespec32 __user *compat_rmtp; }; - u64 expires; + ktime_t expires; } nanosleep; /* For poll */ struct { -- cgit From 4518767be9089ea4f54754ad27364d6134fc46e2 Mon Sep 17 00:00:00 2001 From: Jianyun Gao Date: Sat, 27 Sep 2025 17:34:10 +0800 Subject: time: Fix a few typos in time[r] related code comments Signed-off-by: Jianyun Gao Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20250927093411.1509275-1-jianyungao89@gmail.com --- include/linux/delay.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/delay.h b/include/linux/delay.h index 89866bab100d..46412c00033a 100644 --- a/include/linux/delay.h +++ b/include/linux/delay.h @@ -68,7 +68,7 @@ void usleep_range_state(unsigned long min, unsigned long max, * @min: Minimum time in microseconds to sleep * @max: Maximum time in microseconds to sleep * - * For basic information please refere to usleep_range_state(). + * For basic information please refer to usleep_range_state(). * * The task will be in the state TASK_UNINTERRUPTIBLE during the sleep. */ @@ -82,10 +82,10 @@ static inline void usleep_range(unsigned long min, unsigned long max) * @min: Minimum time in microseconds to sleep * @max: Maximum time in microseconds to sleep * - * For basic information please refere to usleep_range_state(). + * For basic information please refer to usleep_range_state(). * * The sleeping task has the state TASK_IDLE during the sleep to prevent - * contribution to the load avarage. + * contribution to the load average. */ static inline void usleep_range_idle(unsigned long min, unsigned long max) { @@ -96,7 +96,7 @@ static inline void usleep_range_idle(unsigned long min, unsigned long max) * ssleep - wrapper for seconds around msleep * @seconds: Requested sleep duration in seconds * - * Please refere to msleep() for detailed information. + * Please refer to msleep() for detailed information. */ static inline void ssleep(unsigned int seconds) { -- cgit From b56651007fc018effe695a68d48caa6970b23094 Mon Sep 17 00:00:00 2001 From: Yury Norov Date: Thu, 20 Nov 2025 15:56:52 +0100 Subject: cpumask: Add initialiser to use cleanup helpers Now we can simplify a code that allocates cpumasks for local needs. Automatic variables have to be initialized at declaration, or at least before any possibility for the logic to return, so that compiler wouldn't try to call an associate destructor function on a random stack number. Because cpumask_var_t, depending on the CPUMASK_OFFSTACK config, is either a pointer or an array, we have to have a macro for initialization. So define a CPUMASK_VAR_NULL macro, which allows to init struct cpumask pointer with NULL when CPUMASK_OFFSTACK is enabled, and effectively a no-op when CPUMASK_OFFSTACK is disabled (initialisation optimised out with -O2). Signed-off-by: Yury Norov Signed-off-by: Gabriele Monaco Signed-off-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Link: https://patch.msgid.link/20251120145653.296659-7-gmonaco@redhat.com --- include/linux/cpumask.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index ff8f41ab7ce6..68be522449ec 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -1005,6 +1005,7 @@ static __always_inline unsigned int cpumask_size(void) #define this_cpu_cpumask_var_ptr(x) this_cpu_read(x) #define __cpumask_var_read_mostly __read_mostly +#define CPUMASK_VAR_NULL NULL bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node); @@ -1051,6 +1052,7 @@ static __always_inline bool cpumask_available(cpumask_var_t mask) #define this_cpu_cpumask_var_ptr(x) this_cpu_ptr(x) #define __cpumask_var_read_mostly +#define CPUMASK_VAR_NULL {} static __always_inline bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) { -- cgit From 7dec062cfcf27808dbb70a0b231d1a698792743d Mon Sep 17 00:00:00 2001 From: Gabriele Monaco Date: Thu, 20 Nov 2025 15:56:53 +0100 Subject: timers/migration: Exclude isolated cpus from hierarchy The timer migration mechanism allows active CPUs to pull timers from idle ones to improve the overall idle time. This is however undesired when CPU intensive workloads run on isolated cores, as the algorithm would move the timers from housekeeping to isolated cores, negatively affecting the isolation. Exclude isolated cores from the timer migration algorithm, extend the concept of unavailable cores, currently used for offline ones, to isolated ones: * A core is unavailable if isolated or offline; * A core is available if non isolated and online; A core is considered unavailable as isolated if it belongs to: * the isolcpus (domain) list * an isolated cpuset Except if it is: * in the nohz_full list (already idle for the hierarchy) * the nohz timekeeper core (must be available to handle global timers) CPUs are added to the hierarchy during late boot, excluding isolated ones, the hierarchy is also adapted when the cpuset isolation changes. Due to how the timer migration algorithm works, any CPU part of the hierarchy can have their global timers pulled by remote CPUs and have to pull remote timers, only skipping pulling remote timers would break the logic. For this reason, prevent isolated CPUs from pulling remote global timers, but also the other way around: any global timer started on an isolated CPU will run there. This does not break the concept of isolation (global timers don't come from outside the CPU) and, if considered inappropriate, can usually be mitigated with other isolation techniques (e.g. IRQ pinning). This effect was noticed on a 128 cores machine running oslat on the isolated cores (1-31,33-63,65-95,97-127). The tool monopolises CPUs, and the CPU with lowest count in a timer migration hierarchy (here 1 and 65) appears as always active and continuously pulls global timers, from the housekeeping CPUs. This ends up moving driver work (e.g. delayed work) to isolated CPUs and causes latency spikes: before the change: # oslat -c 1-31,33-63,65-95,97-127 -D 62s ... Maximum: 1203 10 3 4 ... 5 (us) after the change: # oslat -c 1-31,33-63,65-95,97-127 -D 62s ... Maximum: 10 4 3 4 3 ... 5 (us) The same behaviour was observed on a machine with as few as 20 cores / 40 threads with isocpus set to: 1-9,11-39 with rtla-osnoise-top. Signed-off-by: Gabriele Monaco Signed-off-by: Thomas Gleixner Tested-by: John B. Wyatt IV Reviewed-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Link: https://patch.msgid.link/20251120145653.296659-8-gmonaco@redhat.com --- include/linux/timer.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux') diff --git a/include/linux/timer.h b/include/linux/timer.h index 0414d9e6b4fc..62e1cea71125 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -188,4 +188,13 @@ int timers_dead_cpu(unsigned int cpu); #define timers_dead_cpu NULL #endif +#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) +extern int tmigr_isolated_exclude_cpumask(struct cpumask *exclude_cpumask); +#else +static inline int tmigr_isolated_exclude_cpumask(struct cpumask *exclude_cpumask) +{ + return 0; +} +#endif + #endif -- cgit