Differential D21740 Diff 65073 head/sys/kern/subr_smp.c

Changeset View

Standalone View

head/sys/kern/subr_smp.c

	Show First 20 Lines • Show All 923 Lines • ▼ Show 20 Lines

	int			int
	quiesce_all_cpus(const char *wmesg, int prio)			quiesce_all_cpus(const char *wmesg, int prio)
	{			{

	return quiesce_cpus(all_cpus, wmesg, prio);			return quiesce_cpus(all_cpus, wmesg, prio);
	}			}

				/*
				* Observe all CPUs not executing in critical section.
				* We are not in one so the check for us is safe. If the found
				* thread changes to something else we know the section was
				* exited as well.
				*/
				void
				quiesce_all_critical(void)
				{
				struct thread td, newtd;
				struct pcpu *pcpu;
				int cpu;

				MPASS(curthread->td_critnest == 0);

				CPU_FOREACH(cpu) {
				pcpu = cpuid_to_pcpu[cpu];
				td = pcpu->pc_curthread;
				for (;;) {
				if (td->td_critnest == 0)
				break;
				cpu_spinwait();
				newtd = (struct thread *)
				atomic_load_acq_ptr((u_long *)pcpu->pc_curthread);
				if (td != newtd)
				break;
				}
				}
				}

				static void
				cpus_fence_seq_cst_issue(void *arg __unused)
				{

				atomic_thread_fence_seq_cst();
				}

				/*
				* Send an IPI forcing a sequentially consistent fence.
				*
				* Allows replacement of an explicitly fence with a compiler barrier.
				* Trades speed up during normal execution for a significant slowdown when
				* the barrier is needed.
				*/
				void
				cpus_fence_seq_cst(void)
				{

				#ifdef SMP
				smp_rendezvous(
				smp_no_rendezvous_barrier,
				cpus_fence_seq_cst_issue,
				smp_no_rendezvous_barrier,
				NULL
				);
				#else
				cpus_fence_seq_cst_issue(NULL);
				#endif
				}

	/* Extra care is taken with this sysctl because the data type is volatile */			/* Extra care is taken with this sysctl because the data type is volatile */
	static int			static int
	sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS)			sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS)
	{			{
	int error, active;			int error, active;

	active = smp_started;			active = smp_started;
	error = SYSCTL_OUT(req, &active, sizeof(active));			error = SYSCTL_OUT(req, &active, sizeof(active));
	▲ Show 20 Lines • Show All 260 Lines • Show Last 20 Lines