/*
* When called the executing CPU will send an IPI to all other CPUs
* requesting that they halt execution.
*
* Usually (but not necessarily) called with 'other_cpus' as its arg.
*
* - Signals all CPUs in map to stop.
* - Waits for each to stop.
*
* Returns:
* -1: error
* 0: NA
* 1: ok
*
*/
static int
generic_stop_cpus(cpuset_t map, u_int type)
{
#ifdef KTR
char cpusetbuf[CPUSETBUFSIZ];
#endif
static volatile u_int stopping_cpu = NOCPU;
int i;
volatile cpuset_t *cpus;
KASSERT(
#if defined(__amd64__) || defined(__i386__)
type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND,
#else
type == IPI_STOP || type == IPI_STOP_HARD,
#endif
("%s: invalid stop type", __func__));
if (!smp_started)
return (0);
CTR2(KTR_SMP, "stop_cpus(%s) with %u type",
cpusetobj_strprint(cpusetbuf, &map), type);
if (stopping_cpu != PCPU_GET(cpuid))
while (atomic_cmpset_int(&stopping_cpu, NOCPU,
PCPU_GET(cpuid)) == 0)
while (stopping_cpu != NOCPU)
cpu_spinwait(); /* spin */
/* send the stop IPI to all CPUs in map */
ipi_selected(map, type);
#if defined(__amd64__) || defined(__i386__)
if (type == IPI_SUSPEND)
cpus = &suspended_cpus;
else
#endif
cpus = &stopped_cpus;
i = 0;
while (!CPU_SUBSET(cpus, &map)) {
/* spin */
cpu_spinwait();
i++;
if (i == 100000000) {
printf("timeout stopping cpus\n");
break;
}
}
stopping_cpu = NOCPU;
return (1);
}
/*
* Create an anonymous set with the provided mask in the space provided by
* 'fset'. If the passed in set is anonymous we use its parent otherwise
* the new set is a child of 'set'.
*/
static int
cpuset_shadow(struct cpuset *set, struct cpuset *fset, const cpuset_t *mask)
{
struct cpuset *parent;
if (set->cs_id == CPUSET_INVALID)
parent = set->cs_parent;
else
parent = set;
if (!CPU_SUBSET(&parent->cs_mask, mask))
return (EDEADLK);
return (_cpuset_create(fset, parent, mask, CPUSET_INVALID));
}
/*
* Modify the set 'set' to use a copy of the mask provided. Apply this new
* mask to restrict all children in the tree. Checks for validity before
* applying the changes.
*/
static int
cpuset_modify(struct cpuset *set, cpuset_t *mask)
{
struct cpuset *root;
int error;
error = priv_check(curthread, PRIV_SCHED_CPUSET);
if (error)
return (error);
/*
* In case we are called from within the jail
* we do not allow modifying the dedicated root
* cpuset of the jail but may still allow to
* change child sets.
*/
if (jailed(curthread->td_ucred) &&
set->cs_flags & CPU_SET_ROOT)
return (EPERM);
/*
* Verify that we have access to this set of
* cpus.
*/
root = set->cs_parent;
if (root && !CPU_SUBSET(&root->cs_mask, mask))
return (EINVAL);
mtx_lock_spin(&cpuset_lock);
error = cpuset_testupdate(set, mask);
if (error)
goto out;
cpuset_update(set, mask);
CPU_COPY(mask, &set->cs_mask);
out:
mtx_unlock_spin(&cpuset_lock);
return (error);
}
/*
* When called the executing CPU will send an IPI to all other CPUs
* requesting that they halt execution.
*
* Usually (but not necessarily) called with 'other_cpus' as its arg.
*
* - Signals all CPUs in map to stop.
* - Waits for each to stop.
*
* Returns:
* -1: error
* 0: NA
* 1: ok
*
*/
static int
generic_stop_cpus(cpuset_t map, u_int type)
{
#ifdef KTR
char cpusetbuf[CPUSETBUFSIZ];
#endif
static volatile u_int stopping_cpu = NOCPU;
int i;
volatile cpuset_t *cpus;
KASSERT(
#if defined(__amd64__) || defined(__i386__)
type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND,
#else
type == IPI_STOP || type == IPI_STOP_HARD,
#endif
("%s: invalid stop type", __func__));
if (!smp_started)
return (0);
CTR2(KTR_SMP, "stop_cpus(%s) with %u type",
cpusetobj_strprint(cpusetbuf, &map), type);
#if defined(__amd64__) || defined(__i386__)
/*
* When suspending, ensure there are are no IPIs in progress.
* IPIs that have been issued, but not yet delivered (e.g.
* not pending on a vCPU when running under virtualization)
* will be lost, violating FreeBSD's assumption of reliable
* IPI delivery.
*/
if (type == IPI_SUSPEND)
mtx_lock_spin(&smp_ipi_mtx);
#endif
if (stopping_cpu != PCPU_GET(cpuid))
while (atomic_cmpset_int(&stopping_cpu, NOCPU,
PCPU_GET(cpuid)) == 0)
while (stopping_cpu != NOCPU)
cpu_spinwait(); /* spin */
/* send the stop IPI to all CPUs in map */
ipi_selected(map, type);
#if defined(__amd64__) || defined(__i386__)
if (type == IPI_SUSPEND)
cpus = &suspended_cpus;
else
#endif
cpus = &stopped_cpus;
i = 0;
while (!CPU_SUBSET(cpus, &map)) {
/* spin */
cpu_spinwait();
i++;
if (i == 100000000) {
printf("timeout stopping cpus\n");
break;
}
}
#if defined(__amd64__) || defined(__i386__)
if (type == IPI_SUSPEND)
mtx_unlock_spin(&smp_ipi_mtx);
#endif
stopping_cpu = NOCPU;
return (1);
}
/*
* Handle two cases for replacing the base set or mask of an entire process.
*
* 1) Set is non-null and mask is null. This reparents all anonymous sets
* to the provided set and replaces all non-anonymous td_cpusets with the
* provided set.
* 2) Mask is non-null and set is null. This replaces or creates anonymous
* sets for every thread with the existing base as a parent.
*
* This is overly complicated because we can't allocate while holding a
* spinlock and spinlocks must be held while changing and examining thread
* state.
*/
static int
cpuset_setproc(pid_t pid, struct cpuset *set, cpuset_t *mask)
{
struct setlist freelist;
struct setlist droplist;
struct cpuset *tdset;
struct cpuset *nset;
struct thread *td;
struct proc *p;
int threads;
int nfree;
int error;
/*
* The algorithm requires two passes due to locking considerations.
*
* 1) Lookup the process and acquire the locks in the required order.
* 2) If enough cpusets have not been allocated release the locks and
* allocate them. Loop.
*/
LIST_INIT(&freelist);
LIST_INIT(&droplist);
nfree = 0;
for (;;) {
error = cpuset_which(CPU_WHICH_PID, pid, &p, &td, &nset);
if (error)
goto out;
if (nfree >= p->p_numthreads)
break;
threads = p->p_numthreads;
PROC_UNLOCK(p);
for (; nfree < threads; nfree++) {
nset = uma_zalloc(cpuset_zone, M_WAITOK);
LIST_INSERT_HEAD(&freelist, nset, cs_link);
}
}
PROC_LOCK_ASSERT(p, MA_OWNED);
/*
* Now that the appropriate locks are held and we have enough cpusets,
* make sure the operation will succeed before applying changes. The
* proc lock prevents td_cpuset from changing between calls.
*/
error = 0;
FOREACH_THREAD_IN_PROC(p, td) {
thread_lock(td);
tdset = td->td_cpuset;
/*
* Verify that a new mask doesn't specify cpus outside of
* the set the thread is a member of.
*/
if (mask) {
if (tdset->cs_id == CPUSET_INVALID)
tdset = tdset->cs_parent;
if (!CPU_SUBSET(&tdset->cs_mask, mask))
error = EDEADLK;
/*
* Verify that a new set won't leave an existing thread
* mask without a cpu to run on. It can, however, restrict
* the set.
*/
} else if (tdset->cs_id == CPUSET_INVALID) {
if (!CPU_OVERLAP(&set->cs_mask, &tdset->cs_mask))
error = EDEADLK;
}
thread_unlock(td);
if (error)
goto unlock_out;
}
