Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core timer updates from Thomas Gleixner:
 "Timers and timekeeping updates:

   - A large overhaul of the posix CPU timer code which is a preparation
     for moving the CPU timer expiry out into task work so it can be
     properly accounted on the task/process.

     An update to the bogus permission checks will come later during the
     merge window as feedback was not complete before heading of for
     travel.

   - Switch the timerqueue code to use cached rbtrees and get rid of the
     homebrewn caching of the leftmost node.

   - Consolidate hrtimer_init() + hrtimer_init_sleeper() calls into a
     single function

   - Implement the separation of hrtimers to be forced to expire in hard
     interrupt context even when PREEMPT_RT is enabled and mark the
     affected timers accordingly.

   - Implement a mechanism for hrtimers and the timer wheel to protect
     RT against priority inversion and live lock issues when a (hr)timer
     which should be canceled is currently executing the callback.
     Instead of infinitely spinning, the task which tries to cancel the
     timer blocks on a per cpu base expiry lock which is held and
     released by the (hr)timer expiry code.

   - Enable the Hyper-V TSC page based sched_clock for Hyper-V guests
     resulting in faster access to timekeeping functions.

   - Updates to various clocksource/clockevent drivers and their device
     tree bindings.

   - The usual small improvements all over the place"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
  posix-cpu-timers: Fix permission check regression
  posix-cpu-timers: Always clear head pointer on dequeue
  hrtimer: Add a missing bracket and hide `migration_base' on !SMP
  posix-cpu-timers: Make expiry_active check actually work correctly
  posix-timers: Unbreak CONFIG_POSIX_TIMERS=n build
  tick: Mark sched_timer to expire in hard interrupt context
  hrtimer: Add kernel doc annotation for HRTIMER_MODE_HARD
  x86/hyperv: Hide pv_ops access for CONFIG_PARAVIRT=n
  posix-cpu-timers: Utilize timerqueue for storage
  posix-cpu-timers: Move state tracking to struct posix_cputimers
  posix-cpu-timers: Deduplicate rlimit handling
  posix-cpu-timers: Remove pointless comparisons
  posix-cpu-timers: Get rid of 64bit divisions
  posix-cpu-timers: Consolidate timer expiry further
  posix-cpu-timers: Get rid of zero checks
  rlimit: Rewrite non-sensical RLIMIT_CPU comment
  posix-cpu-timers: Respect INFINITY for hard RTTIME limit
  posix-cpu-timers: Switch thread group sampling to array
  posix-cpu-timers: Restructure expiry array
  posix-cpu-timers: Remove cputime_expires
  ...

1 files changed, 3 insertions, 31 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 1d1cd06edbc1..53e780748fe3 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1519,28 +1519,17 @@ void __cleanup_sighand(struct sighand_struct *sighand)
 	}
 }
 
-#ifdef CONFIG_POSIX_TIMERS
 /*
  * Initialize POSIX timer handling for a thread group.
  */
 static void posix_cpu_timers_init_group(struct signal_struct *sig)
 {
+	struct posix_cputimers *pct = &sig->posix_cputimers;
 	unsigned long cpu_limit;
 
 	cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
-	if (cpu_limit != RLIM_INFINITY) {
-		sig->cputime_expires.prof_exp = cpu_limit * NSEC_PER_SEC;
-		sig->cputimer.running = true;
-	}
-
-	/* The timer lists. */
-	INIT_LIST_HEAD(&sig->cpu_timers[0]);
-	INIT_LIST_HEAD(&sig->cpu_timers[1]);
-	INIT_LIST_HEAD(&sig->cpu_timers[2]);
+	posix_cputimers_group_init(pct, cpu_limit);
 }
-#else
-static inline void posix_cpu_timers_init_group(struct signal_struct *sig) { }
-#endif
 
 static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
 {
@@ -1642,23 +1631,6 @@ static void rt_mutex_init_task(struct task_struct *p)
 #endif
 }
 
-#ifdef CONFIG_POSIX_TIMERS
-/*
- * Initialize POSIX timer handling for a single task.
- */
-static void posix_cpu_timers_init(struct task_struct *tsk)
-{
-	tsk->cputime_expires.prof_exp = 0;
-	tsk->cputime_expires.virt_exp = 0;
-	tsk->cputime_expires.sched_exp = 0;
-	INIT_LIST_HEAD(&tsk->cpu_timers[0]);
-	INIT_LIST_HEAD(&tsk->cpu_timers[1]);
-	INIT_LIST_HEAD(&tsk->cpu_timers[2]);
-}
-#else
-static inline void posix_cpu_timers_init(struct task_struct *tsk) { }
-#endif
-
 static inline void init_task_pid_links(struct task_struct *task)
 {
 	enum pid_type type;
@@ -1945,7 +1917,7 @@ static __latent_entropy struct task_struct *copy_process(
 	task_io_accounting_init(&p->ioac);
 	acct_clear_integrals(p);
 
-	posix_cpu_timers_init(p);
+	posix_cputimers_init(&p->posix_cputimers);
 
 	p->io_context = NULL;
 	audit_set_context(p, NULL);