The following commit has been merged into the timers/core branch of tip: Commit-ID: 3b495b22d04df3220ccae829bf7c5cadb3059ccf Gitweb: https://git.kernel.org/tip/3b495b22d04df3220ccae829bf7c5cadb3059ccf Author: Thomas Gleixner <t...@linutronix.de> AuthorDate: Wed, 21 Aug 2019 21:09:08 +02:00 Committer: Thomas Gleixner <t...@linutronix.de> CommitterDate: Wed, 28 Aug 2019 11:50:36 +02:00
posix-cpu-timers: Simplify timer queueing Now that the expiry cache can be accessed as an array, the per clock checking can be reduced to just comparing the corresponding array elements. Signed-off-by: Thomas Gleixner <t...@linutronix.de> Reviewed-by: Frederic Weisbecker <frede...@kernel.org> Link: https://lkml.kernel.org/r/20190821192921.212129...@linutronix.de --- kernel/time/posix-cpu-timers.c | 55 ++++++++++++--------------------- 1 file changed, 21 insertions(+), 34 deletions(-) diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index a38b6d0..b132417 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -456,20 +456,20 @@ static inline int expires_gt(u64 expires, u64 new_exp) */ static void arm_timer(struct k_itimer *timer) { + struct cpu_timer_list *const nt = &timer->it.cpu; + int clkidx = CPUCLOCK_WHICH(timer->it_clock); + u64 *cpuexp, newexp = timer->it.cpu.expires; struct task_struct *p = timer->it.cpu.task; struct list_head *head, *listpos; - struct task_cputime *cputime_expires; - struct cpu_timer_list *const nt = &timer->it.cpu; struct cpu_timer_list *next; if (CPUCLOCK_PERTHREAD(timer->it_clock)) { - head = p->posix_cputimers.cpu_timers; - cputime_expires = &p->posix_cputimers.cputime_expires; + head = p->posix_cputimers.cpu_timers + clkidx; + cpuexp = p->posix_cputimers.expiries + clkidx; } else { - head = p->signal->posix_cputimers.cpu_timers; - cputime_expires = &p->signal->posix_cputimers.cputime_expires; + head = p->signal->posix_cputimers.cpu_timers + clkidx; + cpuexp = p->signal->posix_cputimers.expiries + clkidx; } - head += CPUCLOCK_WHICH(timer->it_clock); listpos = head; list_for_each_entry(next, head, entry) { @@ -479,35 +479,22 @@ static void arm_timer(struct k_itimer *timer) } list_add(&nt->entry, listpos); - if (listpos == head) { - u64 exp = nt->expires; + if (listpos != head) + return; - /* - * We are the new earliest-expiring POSIX 1.b timer, hence - * need to update expiration cache. Take into account that - * for process timers we share expiration cache with itimers - * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME. - */ + /* + * We are the new earliest-expiring POSIX 1.b timer, hence + * need to update expiration cache. Take into account that + * for process timers we share expiration cache with itimers + * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME. + */ + if (expires_gt(*cpuexp, newexp)) + *cpuexp = newexp; - switch (CPUCLOCK_WHICH(timer->it_clock)) { - case CPUCLOCK_PROF: - if (expires_gt(cputime_expires->prof_exp, exp)) - cputime_expires->prof_exp = exp; - break; - case CPUCLOCK_VIRT: - if (expires_gt(cputime_expires->virt_exp, exp)) - cputime_expires->virt_exp = exp; - break; - case CPUCLOCK_SCHED: - if (expires_gt(cputime_expires->sched_exp, exp)) - cputime_expires->sched_exp = exp; - break; - } - if (CPUCLOCK_PERTHREAD(timer->it_clock)) - tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER); - else - tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER); - } + if (CPUCLOCK_PERTHREAD(timer->it_clock)) + tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER); + else + tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER); } /*
