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authorIngo Molnar <mingo@elte.hu>2008-09-11 13:37:28 +0200
committerIngo Molnar <mingo@elte.hu>2008-09-11 13:37:28 +0200
commit09b22a2f678ae733801b888c44756d0abd686b8a (patch)
tree6ca52d4011ce6b11c6450d3a574ea6a53cc0d339 /kernel
parent3ba35573ad9a149a3af19625b502679283382f6b (diff)
parentadee14b2e1557d0a8559f29681732d05a89dfc35 (diff)
Merge commit 'v2.6.27-rc6' into sched/devel
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpuset.c312
-rw-r--r--kernel/sched.c19
-rw-r--r--kernel/time/clockevents.c3
-rw-r--r--kernel/time/ntp.c2
-rw-r--r--kernel/time/tick-broadcast.c78
-rw-r--r--kernel/time/tick-common.c1
-rw-r--r--kernel/time/tick-internal.h2
-rw-r--r--kernel/time/tick-oneshot.c44
8 files changed, 296 insertions, 165 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index d5ab79cf516..f227bc17269 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -14,6 +14,8 @@
* 2003-10-22 Updates by Stephen Hemminger.
* 2004 May-July Rework by Paul Jackson.
* 2006 Rework by Paul Menage to use generic cgroups
+ * 2008 Rework of the scheduler domains and CPU hotplug handling
+ * by Max Krasnyansky
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of the Linux
@@ -236,9 +238,11 @@ static struct cpuset top_cpuset = {
static DEFINE_MUTEX(callback_mutex);
-/* This is ugly, but preserves the userspace API for existing cpuset
+/*
+ * This is ugly, but preserves the userspace API for existing cpuset
* users. If someone tries to mount the "cpuset" filesystem, we
- * silently switch it to mount "cgroup" instead */
+ * silently switch it to mount "cgroup" instead
+ */
static int cpuset_get_sb(struct file_system_type *fs_type,
int flags, const char *unused_dev_name,
void *data, struct vfsmount *mnt)
@@ -473,10 +477,9 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
}
/*
- * Helper routine for rebuild_sched_domains().
+ * Helper routine for generate_sched_domains().
* Do cpusets a, b have overlapping cpus_allowed masks?
*/
-
static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
{
return cpus_intersects(a->cpus_allowed, b->cpus_allowed);
@@ -518,26 +521,15 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
}
/*
- * rebuild_sched_domains()
- *
- * This routine will be called to rebuild the scheduler's dynamic
- * sched domains:
- * - if the flag 'sched_load_balance' of any cpuset with non-empty
- * 'cpus' changes,
- * - or if the 'cpus' allowed changes in any cpuset which has that
- * flag enabled,
- * - or if the 'sched_relax_domain_level' of any cpuset which has
- * that flag enabled and with non-empty 'cpus' changes,
- * - or if any cpuset with non-empty 'cpus' is removed,
- * - or if a cpu gets offlined.
- *
- * This routine builds a partial partition of the systems CPUs
- * (the set of non-overlappping cpumask_t's in the array 'part'
- * below), and passes that partial partition to the kernel/sched.c
- * partition_sched_domains() routine, which will rebuild the
- * schedulers load balancing domains (sched domains) as specified
- * by that partial partition. A 'partial partition' is a set of
- * non-overlapping subsets whose union is a subset of that set.
+ * generate_sched_domains()
+ *
+ * This function builds a partial partition of the systems CPUs
+ * A 'partial partition' is a set of non-overlapping subsets whose
+ * union is a subset of that set.
+ * The output of this function needs to be passed to kernel/sched.c
+ * partition_sched_domains() routine, which will rebuild the scheduler's
+ * load balancing domains (sched domains) as specified by that partial
+ * partition.
*
* See "What is sched_load_balance" in Documentation/cpusets.txt
* for a background explanation of this.
@@ -547,13 +539,7 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
* domains when operating in the severe memory shortage situations
* that could cause allocation failures below.
*
- * Call with cgroup_mutex held. May take callback_mutex during
- * call due to the kfifo_alloc() and kmalloc() calls. May nest
- * a call to the get_online_cpus()/put_online_cpus() pair.
- * Must not be called holding callback_mutex, because we must not
- * call get_online_cpus() while holding callback_mutex. Elsewhere
- * the kernel nests callback_mutex inside get_online_cpus() calls.
- * So the reverse nesting would risk an ABBA deadlock.
+ * Must be called with cgroup_lock held.
*
* The three key local variables below are:
* q - a linked-list queue of cpuset pointers, used to implement a
@@ -588,10 +574,10 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
* element of the partition (one sched domain) to be passed to
* partition_sched_domains().
*/
-
-void rebuild_sched_domains(void)
+static int generate_sched_domains(cpumask_t **domains,
+ struct sched_domain_attr **attributes)
{
- LIST_HEAD(q); /* queue of cpusets to be scanned*/
+ LIST_HEAD(q); /* queue of cpusets to be scanned */
struct cpuset *cp; /* scans q */
struct cpuset **csa; /* array of all cpuset ptrs */
int csn; /* how many cpuset ptrs in csa so far */
@@ -601,23 +587,26 @@ void rebuild_sched_domains(void)
int ndoms; /* number of sched domains in result */
int nslot; /* next empty doms[] cpumask_t slot */
- csa = NULL;
+ ndoms = 0;
doms = NULL;
dattr = NULL;
+ csa = NULL;
/* Special case for the 99% of systems with one, full, sched domain */
if (is_sched_load_balance(&top_cpuset)) {
- ndoms = 1;
doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
if (!doms)
- goto rebuild;
+ goto done;
+
dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
if (dattr) {
*dattr = SD_ATTR_INIT;
update_domain_attr_tree(dattr, &top_cpuset);
}
*doms = top_cpuset.cpus_allowed;
- goto rebuild;
+
+ ndoms = 1;
+ goto done;
}
csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);
@@ -680,61 +669,141 @@ restart:
}
}
- /* Convert <csn, csa> to <ndoms, doms> */
+ /*
+ * Now we know how many domains to create.
+ * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
+ */
doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
- if (!doms)
- goto rebuild;
+ if (!doms) {
+ ndoms = 0;
+ goto done;
+ }
+
+ /*
+ * The rest of the code, including the scheduler, can deal with
+ * dattr==NULL case. No need to abort if alloc fails.
+ */
dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL);
for (nslot = 0, i = 0; i < csn; i++) {
struct cpuset *a = csa[i];
+ cpumask_t *dp;
int apn = a->pn;
- if (apn >= 0) {
- cpumask_t *dp = doms + nslot;
-
- if (nslot == ndoms) {
- static int warnings = 10;
- if (warnings) {
- printk(KERN_WARNING
- "rebuild_sched_domains confused:"
- " nslot %d, ndoms %d, csn %d, i %d,"
- " apn %d\n",
- nslot, ndoms, csn, i, apn);
- warnings--;
- }
- continue;
+ if (apn < 0) {
+ /* Skip completed partitions */
+ continue;
+ }
+
+ dp = doms + nslot;
+
+ if (nslot == ndoms) {
+ static int warnings = 10;
+ if (warnings) {
+ printk(KERN_WARNING
+ "rebuild_sched_domains confused:"
+ " nslot %d, ndoms %d, csn %d, i %d,"
+ " apn %d\n",
+ nslot, ndoms, csn, i, apn);
+ warnings--;
}
+ continue;
+ }
- cpus_clear(*dp);
- if (dattr)
- *(dattr + nslot) = SD_ATTR_INIT;
- for (j = i; j < csn; j++) {
- struct cpuset *b = csa[j];
-
- if (apn == b->pn) {
- cpus_or(*dp, *dp, b->cpus_allowed);
- b->pn = -1;
- if (dattr)
- update_domain_attr_tree(dattr
- + nslot, b);
- }
+ cpus_clear(*dp);
+ if (dattr)
+ *(dattr + nslot) = SD_ATTR_INIT;
+ for (j = i; j < csn; j++) {
+ struct cpuset *b = csa[j];
+
+ if (apn == b->pn) {
+ cpus_or(*dp, *dp, b->cpus_allowed);
+ if (dattr)
+ update_domain_attr_tree(dattr + nslot, b);
+
+ /* Done with this partition */
+ b->pn = -1;
}
- nslot++;
}
+ nslot++;
}
BUG_ON(nslot != ndoms);
-rebuild:
- /* Have scheduler rebuild sched domains */
+done:
+ kfree(csa);
+
+ *domains = doms;
+ *attributes = dattr;
+ return ndoms;
+}
+
+/*
+ * Rebuild scheduler domains.
+ *
+ * Call with neither cgroup_mutex held nor within get_online_cpus().
+ * Takes both cgroup_mutex and get_online_cpus().
+ *
+ * Cannot be directly called from cpuset code handling changes
+ * to the cpuset pseudo-filesystem, because it cannot be called
+ * from code that already holds cgroup_mutex.
+ */
+static void do_rebuild_sched_domains(struct work_struct *unused)
+{
+ struct sched_domain_attr *attr;
+ cpumask_t *doms;
+ int ndoms;
+
get_online_cpus();
- partition_sched_domains(ndoms, doms, dattr);
+
+ /* Generate domain masks and attrs */
+ cgroup_lock();
+ ndoms = generate_sched_domains(&doms, &attr);
+ cgroup_unlock();
+
+ /* Have scheduler rebuild the domains */
+ partition_sched_domains(ndoms, doms, attr);
+
put_online_cpus();
+}
-done:
- kfree(csa);
- /* Don't kfree(doms) -- partition_sched_domains() does that. */
- /* Don't kfree(dattr) -- partition_sched_domains() does that. */
+static DECLARE_WORK(rebuild_sched_domains_work, do_rebuild_sched_domains);
+
+/*
+ * Rebuild scheduler domains, asynchronously via workqueue.
+ *
+ * If the flag 'sched_load_balance' of any cpuset with non-empty
+ * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
+ * which has that flag enabled, or if any cpuset with a non-empty
+ * 'cpus' is removed, then call this routine to rebuild the
+ * scheduler's dynamic sched domains.
+ *
+ * The rebuild_sched_domains() and partition_sched_domains()
+ * routines must nest cgroup_lock() inside get_online_cpus(),
+ * but such cpuset changes as these must nest that locking the
+ * other way, holding cgroup_lock() for much of the code.
+ *
+ * So in order to avoid an ABBA deadlock, the cpuset code handling
+ * these user changes delegates the actual sched domain rebuilding
+ * to a separate workqueue thread, which ends up processing the
+ * above do_rebuild_sched_domains() function.
+ */
+static void async_rebuild_sched_domains(void)
+{
+ schedule_work(&rebuild_sched_domains_work);
+}
+
+/*
+ * Accomplishes the same scheduler domain rebuild as the above
+ * async_rebuild_sched_domains(), however it directly calls the
+ * rebuild routine synchronously rather than calling it via an
+ * asynchronous work thread.
+ *
+ * This can only be called from code that is not holding
+ * cgroup_mutex (not nested in a cgroup_lock() call.)
+ */
+void rebuild_sched_domains(void)
+{
+ do_rebuild_sched_domains(NULL);
}
/**
@@ -863,7 +932,7 @@ static int update_cpumask(struct cpuset *cs, const char *buf)
return retval;
if (is_load_balanced)
- rebuild_sched_domains();
+ async_rebuild_sched_domains();
return 0;
}
@@ -1090,7 +1159,7 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
if (val != cs->relax_domain_level) {
cs->relax_domain_level = val;
if (!cpus_empty(cs->cpus_allowed) && is_sched_load_balance(cs))
- rebuild_sched_domains();
+ async_rebuild_sched_domains();
}
return 0;
@@ -1131,7 +1200,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
mutex_unlock(&callback_mutex);
if (cpus_nonempty && balance_flag_changed)
- rebuild_sched_domains();
+ async_rebuild_sched_domains();
return 0;
}
@@ -1492,6 +1561,9 @@ static u64 cpuset_read_u64(struct cgroup *cont, struct cftype *cft)
default:
BUG();
}
+
+ /* Unreachable but makes gcc happy */
+ return 0;
}
static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft)
@@ -1504,6 +1576,9 @@ static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft)
default:
BUG();
}
+
+ /* Unrechable but makes gcc happy */
+ return 0;
}
@@ -1692,15 +1767,9 @@ static struct cgroup_subsys_state *cpuset_create(
}
/*
- * Locking note on the strange update_flag() call below:
- *
* If the cpuset being removed has its flag 'sched_load_balance'
* enabled, then simulate turning sched_load_balance off, which
- * will call rebuild_sched_domains(). The get_online_cpus()
- * call in rebuild_sched_domains() must not be made while holding
- * callback_mutex. Elsewhere the kernel nests callback_mutex inside
- * get_online_cpus() calls. So the reverse nesting would risk an
- * ABBA deadlock.
+ * will call async_rebuild_sched_domains().
*/
static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
@@ -1719,7 +1788,7 @@ static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
struct cgroup_subsys cpuset_subsys = {
.name = "cpuset",
.create = cpuset_create,
- .destroy = cpuset_destroy,
+ .destroy = cpuset_destroy,
.can_attach = cpuset_can_attach,
.attach = cpuset_attach,
.populate = cpuset_populate,
@@ -1811,7 +1880,7 @@ static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to)
}
/*
- * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
+ * If CPU and/or memory hotplug handlers, below, unplug any CPUs
* or memory nodes, we need to walk over the cpuset hierarchy,
* removing that CPU or node from all cpusets. If this removes the
* last CPU or node from a cpuset, then move the tasks in the empty
@@ -1903,35 +1972,6 @@ static void scan_for_empty_cpusets(const struct cpuset *root)
}
/*
- * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
- * cpu_online_map and node_states[N_HIGH_MEMORY]. Force the top cpuset to
- * track what's online after any CPU or memory node hotplug or unplug event.
- *
- * Since there are two callers of this routine, one for CPU hotplug
- * events and one for memory node hotplug events, we could have coded
- * two separate routines here. We code it as a single common routine
- * in order to minimize text size.
- */
-
-static void common_cpu_mem_hotplug_unplug(int rebuild_sd)
-{
- cgroup_lock();
-
- top_cpuset.cpus_allowed = cpu_online_map;
- top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
- scan_for_empty_cpusets(&top_cpuset);
-
- /*
- * Scheduler destroys domains on hotplug events.
- * Rebuild them based on the current settings.
- */
- if (rebuild_sd)
- rebuild_sched_domains();
-
- cgroup_unlock();
-}
-
-/*
* The top_cpuset tracks what CPUs and Memory Nodes are online,
* period. This is necessary in order to make cpusets transparent
* (of no affect) on systems that are actively using CPU hotplug
@@ -1939,40 +1979,52 @@ static void common_cpu_mem_hotplug_unplug(int rebuild_sd)
*
* This routine ensures that top_cpuset.cpus_allowed tracks
* cpu_online_map on each CPU hotplug (cpuhp) event.
+ *
+ * Called within get_online_cpus(). Needs to call cgroup_lock()
+ * before calling generate_sched_domains().
*/
-
-static int cpuset_handle_cpuhp(struct notifier_block *unused_nb,
+static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
unsigned long phase, void *unused_cpu)
{
+ struct sched_domain_attr *attr;
+ cpumask_t *doms;
+ int ndoms;
+
switch (phase) {
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
case CPU_DEAD:
case CPU_DEAD_FROZEN:
- common_cpu_mem_hotplug_unplug(1);
break;
+
default:
return NOTIFY_DONE;
}
+ cgroup_lock();
+ top_cpuset.cpus_allowed = cpu_online_map;
+ scan_for_empty_cpusets(&top_cpuset);
+ ndoms = generate_sched_domains(&doms, &attr);
+ cgroup_unlock();
+
+ /* Have scheduler rebuild the domains */
+ partition_sched_domains(ndoms, doms, attr);
+
return NOTIFY_OK;
}
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY].
- * Call this routine anytime after you change
- * node_states[N_HIGH_MEMORY].
- * See also the previous routine cpuset_handle_cpuhp().
+ * Call this routine anytime after node_states[N_HIGH_MEMORY] changes.
+ * See also the previous routine cpuset_track_online_cpus().
*/
-
void cpuset_track_online_nodes(void)
{
- common_cpu_mem_hotplug_unplug(0);
+ cgroup_lock();
+ top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
+ scan_for_empty_cpusets(&top_cpuset);
+ cgroup_unlock();
}
#endif
@@ -1987,7 +2039,7 @@ void __init cpuset_init_smp(void)
top_cpuset.cpus_allowed = cpu_online_map;
top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
- hotcpu_notifier(cpuset_handle_cpuhp, 0);
+ hotcpu_notifier(cpuset_track_online_cpus, 0);
}
/**
diff --git a/kernel/sched.c b/kernel/sched.c
index 8626ae50ce0..0d8905a1b8c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7746,24 +7746,27 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
* and partition_sched_domains() will fallback to the single partition
* 'fallback_doms', it also forces the domains to be rebuilt.
*
+ * If doms_new==NULL it will be replaced with cpu_online_map.
+ * ndoms_new==0 is a special case for destroying existing domains.
+ * It will not create the default domain.
+ *
* Call with hotplug lock held
*/
void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
struct sched_domain_attr *dattr_new)
{
- int i, j;
+ int i, j, n;
mutex_lock(&sched_domains_mutex);
/* always unregister in case we don't destroy any domains */
unregister_sched_domain_sysctl();
- if (doms_new == NULL)
- ndoms_new = 0;
+ n = doms_new ? ndoms_new : 0;
/* Destroy deleted domains */
for (i = 0; i < ndoms_cur; i++) {
- for (j = 0; j < ndoms_new; j++) {
+ for (j = 0; j < n; j++) {
if (cpus_equal(doms_cur[i], doms_new[j])
&& dattrs_equal(dattr_cur, i, dattr_new, j))
goto match1;
@@ -7776,7 +7779,6 @@ match1:
if (doms_new == NULL) {
ndoms_cur = 0;
- ndoms_new = 1;
doms_new = &fallback_doms;
cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
dattr_new = NULL;
@@ -7813,8 +7815,13 @@ match2:
int arch_reinit_sched_domains(void)
{
get_online_cpus();
+
+ /* Destroy domains first to force the rebuild */
+ partition_sched_domains(0, NULL, NULL);
+
rebuild_sched_domains();
put_online_cpus();
+
return 0;
}
@@ -7898,7 +7905,7 @@ static int update_sched_domains(struct notifier_block *nfb,
case CPU_ONLINE_FROZEN:
case CPU_DEAD:
case CPU_DEAD_FROZEN:
- partition_sched_domains(0, NULL, NULL);
+ partition_sched_domains(1, NULL, NULL);
return NOTIFY_OK;
default:
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 3d1e3e1a197..1876b526c77 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -177,7 +177,7 @@ void clockevents_register_device(struct clock_event_device *dev)
/*
* Noop handler when we shut down an event device
*/
-static void clockevents_handle_noop(struct clock_event_device *dev)
+void clockevents_handle_noop(struct clock_event_device *dev)
{
}
@@ -199,7 +199,6 @@ void clockevents_exchange_device(struct clock_event_device *old,
* released list and do a notify add later.
*/
if (old) {
- old->event_handler = clockevents_handle_noop;
clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
list_del(&old->list);
list_add(&old->list, &clockevents_released);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 5125ddd8196..1ad46f3df6e 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -245,7 +245,7 @@ static void sync_cmos_clock(unsigned long dummy)
if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
fail = update_persistent_clock(now);
- next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
+ next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
if (next.tv_nsec <= 0)
next.tv_nsec += NSEC_PER_SEC;
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 31463d370b9..2f5a38294bf 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -175,6 +175,8 @@ static void tick_do_periodic_broadcast(void)
*/
static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
{
+ ktime_t next;
+
tick_do_periodic_broadcast();
/*
@@ -185,10 +187,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
/*
* Setup the next period for devices, which do not have
- * periodic mode:
+ * periodic mode. We read dev->next_event first and add to it
+ * when the event alrady expired. clockevents_program_event()
+ * sets dev->next_event only when the event is really
+ * programmed to the device.
*/
- for (;;) {
- ktime_t next = ktime_add(dev->next_event, tick_period);
+ for (next = dev->next_event; ;) {
+ next = ktime_add(next, tick_period);
if (!clockevents_program_event(dev, next, ktime_get()))
return;
@@ -205,7 +210,7 @@ static void tick_do_broadcast_on_off(void *why)
struct clock_event_device *bc, *dev;
struct tick_device *td;
unsigned long flags, *reason = why;
- int cpu;
+ int cpu, bc_stopped;
spin_lock_irqsave(&tick_broadcast_lock, flags);
@@ -223,6 +228,8 @@ static void tick_do_broadcast_on_off(void *why)
if (!tick_device_is_functional(dev))
goto out;
+ bc_stopped = cpus_empty(tick_broadcast_mask);
+
switch (*reason) {
case CLOCK_EVT_NOTIFY_BROADCAST_ON:
case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
@@ -245,9 +252,10 @@ static void tick_do_broadcast_on_off(void *why)
break;
}
- if (cpus_empty(tick_broadcast_mask))
- clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
- else {
+ if (cpus_empty(tick_broadcast_mask)) {
+ if (!bc_stopped)
+ clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+ } else if (bc_stopped) {
if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
tick_broadcast_start_periodic(bc);
else
@@ -364,16 +372,8 @@ cpumask_t *tick_get_broadcast_oneshot_mask(void)
static int tick_broadcast_set_event(ktime_t expires, int force)
{
struct clock_event_device *bc = tick_broadcast_device.evtdev;
- ktime_t now = ktime_get();
- int res;
-
- for(;;) {
- res = clockevents_program_event(bc, expires, now);
- if (!res || !force)
- return res;
- now = ktime_get();
- expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
- }
+
+ return tick_dev_program_event(bc, expires, force);
}
int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
@@ -491,14 +491,52 @@ static void tick_broadcast_clear_oneshot(int cpu)
cpu_clear(cpu, tick_broadcast_oneshot_mask);
}
+static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires)
+{
+ struct tick_device *td;
+ int cpu;
+
+ for_each_cpu_mask_nr(cpu, *mask) {
+ td = &per_cpu(tick_cpu_device, cpu);
+ if (td->evtdev)
+ td->evtdev->next_event = expires;
+ }
+}
+
/**
* tick_broadcast_setup_oneshot - setup the broadcast device
*/
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
- bc->event_handler = tick_handle_oneshot_broadcast;
- clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
- bc->next_event.tv64 = KTIME_MAX;
+ /* Set it up only once ! */
+ if (bc->event_handler != tick_handle_oneshot_broadcast) {
+ int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
+ int cpu = smp_processor_id();
+ cpumask_t mask;
+
+ bc->event_handler = tick_handle_oneshot_broadcast;
+ clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+
+ /* Take the do_timer update */
+ tick_do_timer_cpu = cpu;
+
+ /*
+ * We must be careful here. There might be other CPUs
+ * waiting for periodic broadcast. We need to set the
+ * oneshot_mask bits for those and program the
+ * broadcast device to fire.
+ */
+ mask = tick_broadcast_mask;
+ cpu_clear(cpu, mask);
+ cpus_or(tick_broadcast_oneshot_mask,
+ tick_broadcast_oneshot_mask, mask);
+
+ if (was_periodic && !cpus_empty(mask)) {
+ tick_broadcast_init_next_event(&mask, tick_next_period);
+ tick_broadcast_set_event(tick_next_period, 1);
+ } else
+ bc->next_event.tv64 = KTIME_MAX;
+ }
}
/*
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 80c4336f418..c4777193d56 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -161,6 +161,7 @@ static void tick_setup_device(struct tick_device *td,
} else {
handler = td->evtdev->event_handler;
next_event = td->evtdev->next_event;
+ td->evtdev->event_handler = clockevents_handle_noop;
}
td->evtdev = newdev;
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f13f2b7f4fd..0ffc2918ea6 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -17,6 +17,8 @@ extern void tick_handle_periodic(struct clock_event_device *dev);
extern void tick_setup_oneshot(struct clock_event_device *newdev,
void (*handler)(struct clock_event_device *),
ktime_t nextevt);
+extern int tick_dev_program_event(struct clock_event_device *dev,
+ ktime_t expires, int force);
extern int tick_program_event(ktime_t expires, int force);
extern void tick_oneshot_notify(void);
extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 450c04935b6..2e8de678e76 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -23,24 +23,56 @@
#include "tick-internal.h"
/**
- * tick_program_event
+ * tick_program_event internal worker function
*/
-int tick_program_event(ktime_t expires, int force)
+int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
+ int force)
{
- struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
ktime_t now = ktime_get();
+ int i;
- while (1) {
+ for (i = 0;;) {
int ret = clockevents_program_event(dev, expires, now);
if (!ret || !force)
return ret;
+
+ /*
+ * We tried 2 times to program the device with the given
+ * min_delta_ns. If that's not working then we double it
+ * and emit a warning.
+ */
+ if (++i > 2) {
+ /* Increase the min. delta and try again */
+ if (!dev->min_delta_ns)
+ dev->min_delta_ns = 5000;
+ else
+ dev->min_delta_ns += dev->min_delta_ns >> 1;
+
+ printk(KERN_WARNING
+ "CE: %s increasing min_delta_ns to %lu nsec\n",
+ dev->name ? dev->name : "?",
+ dev->min_delta_ns << 1);
+
+ i = 0;
+ }
+
now = ktime_get();
- expires = ktime_add(now, ktime_set(0, dev->min_delta_ns));
+ expires = ktime_add_ns(now, dev->min_delta_ns);
}
}
/**
+ * tick_program_event
+ */
+int tick_program_event(ktime_t expires, int force)
+{
+ struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
+
+ return tick_dev_program_event(dev, expires, force);
+}
+
+/**
* tick_resume_onshot - resume oneshot mode
*/
void tick_resume_oneshot(void)
@@ -61,7 +93,7 @@ void tick_setup_oneshot(struct clock_event_device *newdev,
{
newdev->event_handler = handler;
clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT);
- clockevents_program_event(newdev, next_event, ktime_get());
+ tick_dev_program_event(newdev, next_event, 1);
}
/**