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Commit 244d49e3 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

posix-cpu-timers: Move state tracking to struct posix_cputimers 



Put it where it belongs and clean up the ifdeffery in fork completely.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190821192922.743229404@linutronix.de
parent 8991afe2

include/linux/posix-timers.h

+8 −0
Original line number Diff line number Diff line
@@ -77,15 +77,23 @@ struct posix_cputimer_base { 
/**

 * posix_cputimers - Container for posix CPU timer related data

 * @bases:		Base container for posix CPU clocks

 * @timers_active:	Timers are queued.

 * @expiry_active:	Timer expiry is active. Used for

 *			process wide timers to avoid multiple

 *			task trying to handle expiry concurrently

 *

 * Used in task_struct and signal_struct

 */

struct posix_cputimers {

	struct posix_cputimer_base	bases[CPUCLOCK_MAX];

	unsigned int			timers_active;

	unsigned int			expiry_active;

};



static inline void posix_cputimers_init(struct posix_cputimers *pct)

{

	pct->timers_active = 0;

	pct->expiry_active = 0;

	pct->bases[0].nextevt = U64_MAX;

	pct->bases[1].nextevt = U64_MAX;

	pct->bases[2].nextevt = U64_MAX;

include/linux/sched/cputime.h

+6 −3
Original line number Diff line number Diff line
@@ -70,7 +70,7 @@ void thread_group_sample_cputime(struct task_struct *tsk, u64 *samples); 
 */



/**

 * get_running_cputimer - return &tsk->signal->cputimer if cputimer is running

 * get_running_cputimer - return &tsk->signal->cputimer if cputimers are active

 *

 * @tsk:	Pointer to target task.

 */
@@ -80,8 +80,11 @@ struct thread_group_cputimer *get_running_cputimer(struct task_struct *tsk) 
{

	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;



	/* Check if cputimer isn't running. This is accessed without locking. */

	if (!READ_ONCE(cputimer->running))

	/*

	 * Check whether posix CPU timers are active. If not the thread

	 * group accounting is not active either. Lockless check.

	 */

	if (!READ_ONCE(tsk->signal->posix_cputimers.timers_active))

		return NULL;



	/*

include/linux/sched/signal.h

+0 −6
Original line number Diff line number Diff line
@@ -57,18 +57,12 @@ struct task_cputime_atomic { 
/**

 * struct thread_group_cputimer - thread group interval timer counts

 * @cputime_atomic:	atomic thread group interval timers.

 * @running:		true when there are timers running and

 *			@cputime_atomic receives updates.

 * @checking_timer:	true when a thread in the group is in the

 *			process of checking for thread group timers.

 *

 * This structure contains the version of task_cputime, above, that is

 * used for thread group CPU timer calculations.

 */

struct thread_group_cputimer {

	struct task_cputime_atomic cputime_atomic;

	bool running;

	bool checking_timer;

};



struct multiprocess_signals {

init/init_task.c

+0 −2
Original line number Diff line number Diff line
@@ -30,8 +30,6 @@ static struct signal_struct init_signals = { 
	.posix_timers = LIST_HEAD_INIT(init_signals.posix_timers),

	.cputimer	= {

		.cputime_atomic	= INIT_CPUTIME_ATOMIC,

		.running	= false,

		.checking_timer = false,

	},

#endif

	INIT_CPU_TIMERS(init_signals)

kernel/fork.c

+0 −6
Original line number Diff line number Diff line
@@ -1517,7 +1517,6 @@ void __cleanup_sighand(struct sighand_struct *sighand) 
	}

}



#ifdef CONFIG_POSIX_TIMERS

/*

 * Initialize POSIX timer handling for a thread group.

 */
@@ -1528,12 +1527,7 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig) 


	cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);

	posix_cputimers_group_init(pct, cpu_limit);

	if (cpu_limit != RLIM_INFINITY)

		sig->cputimer.running = true;

}

#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)

{