Dear RT folks!
I'm pleased to announce the v5.4.17-rt9 patch set.
Changes since v5.4.17-rt8:
- A rework of percpu-rwsem locking. The fs core was using a
percpu-rwsem and returned with acquired lock to userland during
`fsfreeze' which led warnings. On !RT the warnings were disabled but
the same lockdep trick did not work on RT.
Reported by Juri Lelli, patch(es) by Peter Zijlstra.
- Include a header file the `current' macro to not break an allmod
build on ARM.
- A tweak to migrate_enable() to not having to wait until
stop_one_cpu_nowait() finishes in case CPU-mask changed during
migrate_disable() and the CPU has to be changed. Patch by Scott
Wood.
- Drop a lock earlier in mm/memcontrol. Not a bug but there is no need
for the additional locked section. Patch by Matt Fleming.
Known issues
- None
The delta patch against v5.4.17-rt8 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.4/incr/patch-5.4.17-rt8-rt9.patch.xz
You can get this release via the git tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v5.4.17-rt9
The RT patch against v5.4.17 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patch-5.4.17-rt9.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.17-rt9.tar.xz
Sebastian
diff --git a/include/linux/locallock.h b/include/linux/locallock.h
index 05a15110c8aa7..9b6b4def52d49 100644
--- a/include/linux/locallock.h
+++ b/include/linux/locallock.h
@@ -3,6 +3,7 @@
#include <linux/percpu.h>
#include <linux/spinlock.h>
+#include <asm/current.h>
#ifdef CONFIG_PREEMPT_RT
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 9fa9a1dd9a11a..6e8d3871450a4 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -3,41 +3,52 @@
#define _LINUX_PERCPU_RWSEM_H
#include <linux/atomic.h>
-#include <linux/rwsem.h>
#include <linux/percpu.h>
#include <linux/rcuwait.h>
+#include <linux/wait.h>
#include <linux/rcu_sync.h>
#include <linux/lockdep.h>
struct percpu_rw_semaphore {
struct rcu_sync rss;
unsigned int __percpu *read_count;
- struct rw_semaphore rw_sem; /* slowpath */
- struct rcuwait writer; /* blocked writer */
- int readers_block;
+ struct rcuwait writer;
+ wait_queue_head_t waiters;
+ atomic_t block;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif
};
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname) .dep_map = { .name = #lockname },
+#else
+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname)
+#endif
+
#define __DEFINE_PERCPU_RWSEM(name, is_static) \
static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name); \
is_static struct percpu_rw_semaphore name = { \
.rss = __RCU_SYNC_INITIALIZER(name.rss), \
.read_count = &__percpu_rwsem_rc_##name, \
- .rw_sem = __RWSEM_INITIALIZER(name.rw_sem), \
.writer = __RCUWAIT_INITIALIZER(name.writer), \
+ .waiters = __WAIT_QUEUE_HEAD_INITIALIZER(name.waiters), \
+ .block = ATOMIC_INIT(0), \
+ __PERCPU_RWSEM_DEP_MAP_INIT(name) \
}
+
#define DEFINE_PERCPU_RWSEM(name) \
__DEFINE_PERCPU_RWSEM(name, /* not static */)
#define DEFINE_STATIC_PERCPU_RWSEM(name) \
__DEFINE_PERCPU_RWSEM(name, static)
-extern int __percpu_down_read(struct percpu_rw_semaphore *, int);
-extern void __percpu_up_read(struct percpu_rw_semaphore *);
+extern bool __percpu_down_read(struct percpu_rw_semaphore *, bool);
static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
{
might_sleep();
- rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 0, _RET_IP_);
+ rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
preempt_disable();
/*
@@ -48,8 +59,9 @@ static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
* and that once the synchronize_rcu() is done, the writer will see
* anything we did within this RCU-sched read-size critical section.
*/
- __this_cpu_inc(*sem->read_count);
- if (unlikely(!rcu_sync_is_idle(&sem->rss)))
+ if (likely(rcu_sync_is_idle(&sem->rss)))
+ __this_cpu_inc(*sem->read_count);
+ else
__percpu_down_read(sem, false); /* Unconditional memory barrier */
/*
* The preempt_enable() prevents the compiler from
@@ -58,16 +70,17 @@ static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
preempt_enable();
}
-static inline int percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
+static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
{
- int ret = 1;
+ bool ret = true;
preempt_disable();
/*
* Same as in percpu_down_read().
*/
- __this_cpu_inc(*sem->read_count);
- if (unlikely(!rcu_sync_is_idle(&sem->rss)))
+ if (likely(rcu_sync_is_idle(&sem->rss)))
+ __this_cpu_inc(*sem->read_count);
+ else
ret = __percpu_down_read(sem, true); /* Unconditional memory barrier */
preempt_enable();
/*
@@ -76,24 +89,36 @@ static inline int percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
*/
if (ret)
- rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 1, _RET_IP_);
+ rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
return ret;
}
static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
{
+ rwsem_release(&sem->dep_map, 1, _RET_IP_);
+
preempt_disable();
/*
* Same as in percpu_down_read().
*/
- if (likely(rcu_sync_is_idle(&sem->rss)))
+ if (likely(rcu_sync_is_idle(&sem->rss))) {
__this_cpu_dec(*sem->read_count);
- else
- __percpu_up_read(sem); /* Unconditional memory barrier */
+ } else {
+ /*
+ * slowpath; reader will only ever wake a single blocked
+ * writer.
+ */
+ smp_mb(); /* B matches C */
+ /*
+ * In other words, if they see our decrement (presumably to
+ * aggregate zero, as that is the only time it matters) they
+ * will also see our critical section.
+ */
+ __this_cpu_dec(*sem->read_count);
+ rcuwait_wake_up(&sem->writer);
+ }
preempt_enable();
-
- rwsem_release(&sem->rw_sem.dep_map, 1, _RET_IP_);
}
extern void percpu_down_write(struct percpu_rw_semaphore *);
@@ -110,29 +135,19 @@ extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
__percpu_init_rwsem(sem, #sem, &rwsem_key); \
})
-#define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)
-
-#define percpu_rwsem_assert_held(sem) \
- lockdep_assert_held(&(sem)->rw_sem)
+#define percpu_rwsem_is_held(sem) lockdep_is_held(sem)
+#define percpu_rwsem_assert_held(sem) lockdep_assert_held(sem)
static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
bool read, unsigned long ip)
{
- lock_release(&sem->rw_sem.dep_map, 1, ip);
-#if defined(CONFIG_RWSEM_SPIN_ON_OWNER) && !defined(CONFIG_PREEMPT_RT)
- if (!read)
- atomic_long_set(&sem->rw_sem.owner, RWSEM_OWNER_UNKNOWN);
-#endif
+ lock_release(&sem->dep_map, 1, ip);
}
static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
bool read, unsigned long ip)
{
- lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
-#if defined(CONFIG_RWSEM_SPIN_ON_OWNER) && !defined(CONFIG_PREEMPT_RT)
- if (!read)
- atomic_long_set(&sem->rw_sem.owner, (long)current);
-#endif
+ lock_acquire(&sem->dep_map, 0, 1, read, 1, NULL, ip);
}
#endif
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index b240dd987834f..393f4520befc9 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -58,12 +58,6 @@ struct rw_semaphore {
#endif
};
-/*
- * Setting all bits of the owner field except bit 0 will indicate
- * that the rwsem is writer-owned with an unknown owner.
- */
-#define RWSEM_OWNER_UNKNOWN (-2L)
-
/* In all implementations count != 0 means locked */
static inline int rwsem_is_locked(struct rw_semaphore *sem)
{
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 2090f205b5c68..1781c47d81f0b 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -21,6 +21,7 @@ int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int
#define WQ_FLAG_EXCLUSIVE 0x01
#define WQ_FLAG_WOKEN 0x02
#define WQ_FLAG_BOOKMARK 0x04
+#define WQ_FLAG_CUSTOM 0x08
/*
* A single wait-queue entry structure:
diff --git a/kernel/cpu.c b/kernel/cpu.c
index a24fd4763263e..368309e9a1f52 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -331,12 +331,12 @@ void lockdep_assert_cpus_held(void)
static void lockdep_acquire_cpus_lock(void)
{
- rwsem_acquire(&cpu_hotplug_lock.rw_sem.dep_map, 0, 0, _THIS_IP_);
+ rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_);
}
static void lockdep_release_cpus_lock(void)
{
- rwsem_release(&cpu_hotplug_lock.rw_sem.dep_map, 1, _THIS_IP_);
+ rwsem_release(&cpu_hotplug_lock.dep_map, 1, _THIS_IP_);
}
/*
diff --git a/kernel/exit.c b/kernel/exit.c
index d659c84716b46..dcb1f1182101e 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -258,6 +258,7 @@ void rcuwait_wake_up(struct rcuwait *w)
wake_up_process(task);
rcu_read_unlock();
}
+EXPORT_SYMBOL_GPL(rcuwait_wake_up);
/*
* Determine if a process group is "orphaned", according to the POSIX
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index 364d38a0c4441..e4a4a56037bb2 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -1,27 +1,29 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/atomic.h>
-#include <linux/rwsem.h>
#include <linux/percpu.h>
+#include <linux/wait.h>
#include <linux/lockdep.h>
#include <linux/percpu-rwsem.h>
#include <linux/rcupdate.h>
#include <linux/sched.h>
+#include <linux/sched/task.h>
#include <linux/errno.h>
-#include "rwsem.h"
-
int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
- const char *name, struct lock_class_key *rwsem_key)
+ const char *name, struct lock_class_key *key)
{
sem->read_count = alloc_percpu(int);
if (unlikely(!sem->read_count))
return -ENOMEM;
- /* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */
rcu_sync_init(&sem->rss);
- __init_rwsem(&sem->rw_sem, name, rwsem_key);
rcuwait_init(&sem->writer);
- sem->readers_block = 0;
+ init_waitqueue_head(&sem->waiters);
+ atomic_set(&sem->block, 0);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+ lockdep_init_map(&sem->dep_map, name, key, 0);
+#endif
return 0;
}
EXPORT_SYMBOL_GPL(__percpu_init_rwsem);
@@ -41,73 +43,139 @@ void percpu_free_rwsem(struct percpu_rw_semaphore *sem)
}
EXPORT_SYMBOL_GPL(percpu_free_rwsem);
-int __percpu_down_read(struct percpu_rw_semaphore *sem, int try)
+static bool __percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
{
+ __this_cpu_inc(*sem->read_count);
+
/*
* Due to having preemption disabled the decrement happens on
* the same CPU as the increment, avoiding the
* increment-on-one-CPU-and-decrement-on-another problem.
*
- * If the reader misses the writer's assignment of readers_block, then
- * the writer is guaranteed to see the reader's increment.
+ * If the reader misses the writer's assignment of sem->block, then the
+ * writer is guaranteed to see the reader's increment.
*
* Conversely, any readers that increment their sem->read_count after
- * the writer looks are guaranteed to see the readers_block value,
- * which in turn means that they are guaranteed to immediately
- * decrement their sem->read_count, so that it doesn't matter that the
- * writer missed them.
+ * the writer looks are guaranteed to see the sem->block value, which
+ * in turn means that they are guaranteed to immediately decrement
+ * their sem->read_count, so that it doesn't matter that the writer
+ * missed them.
*/
smp_mb(); /* A matches D */
/*
- * If !readers_block the critical section starts here, matched by the
+ * If !sem->block the critical section starts here, matched by the
* release in percpu_up_write().
*/
- if (likely(!smp_load_acquire(&sem->readers_block)))
- return 1;
+ if (likely(!atomic_read_acquire(&sem->block)))
+ return true;
- /*
- * Per the above comment; we still have preemption disabled and
- * will thus decrement on the same CPU as we incremented.
- */
- __percpu_up_read(sem);
-
- if (try)
- return 0;
-
- /*
- * We either call schedule() in the wait, or we'll fall through
- * and reschedule on the preempt_enable() in percpu_down_read().
- */
- preempt_enable_no_resched();
-
- /*
- * Avoid lockdep for the down/up_read() we already have them.
- */
- __down_read(&sem->rw_sem);
- this_cpu_inc(*sem->read_count);
- __up_read(&sem->rw_sem);
-
- preempt_disable();
- return 1;
-}
-EXPORT_SYMBOL_GPL(__percpu_down_read);
-
-void __percpu_up_read(struct percpu_rw_semaphore *sem)
-{
- smp_mb(); /* B matches C */
- /*
- * In other words, if they see our decrement (presumably to aggregate
- * zero, as that is the only time it matters) they will also see our
- * critical section.
- */
__this_cpu_dec(*sem->read_count);
- /* Prod writer to recheck readers_active */
+ /* Prod writer to re-evaluate readers_active_check() */
rcuwait_wake_up(&sem->writer);
+
+ return false;
}
-EXPORT_SYMBOL_GPL(__percpu_up_read);
+
+static inline bool __percpu_down_write_trylock(struct percpu_rw_semaphore *sem)
+{
+ if (atomic_read(&sem->block))
+ return false;
+
+ return atomic_xchg(&sem->block, 1) == 0;
+}
+
+static bool __percpu_rwsem_trylock(struct percpu_rw_semaphore *sem, bool reader)
+{
+ if (reader) {
+ bool ret;
+
+ preempt_disable();
+ ret = __percpu_down_read_trylock(sem);
+ preempt_enable();
+
+ return ret;
+ }
+ return __percpu_down_write_trylock(sem);
+}
+
+/*
+ * The return value of wait_queue_entry::func means:
+ *
+ * <0 - error, wakeup is terminated and the error is returned
+ * 0 - no wakeup, a next waiter is tried
+ * >0 - woken, if EXCLUSIVE, counted towards @nr_exclusive.
+ *
+ * We use EXCLUSIVE for both readers and writers to preserve FIFO order,
+ * and play games with the return value to allow waking multiple readers.
+ *
+ * Specifically, we wake readers until we've woken a single writer, or until a
+ * trylock fails.
+ */
+static int percpu_rwsem_wake_function(struct wait_queue_entry *wq_entry,
+ unsigned int mode, int wake_flags,
+ void *key)
+{
+ struct task_struct *p = get_task_struct(wq_entry->private);
+ bool reader = wq_entry->flags & WQ_FLAG_CUSTOM;
+ struct percpu_rw_semaphore *sem = key;
+
+ /* concurrent against percpu_down_write(), can get stolen */
+ if (!__percpu_rwsem_trylock(sem, reader))
+ return 1;
+
+ list_del_init(&wq_entry->entry);
+ smp_store_release(&wq_entry->private, NULL);
+
+ wake_up_process(p);
+ put_task_struct(p);
+
+ return !reader; /* wake (readers until) 1 writer */
+}
+
+static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader)
+{
+ DEFINE_WAIT_FUNC(wq_entry, percpu_rwsem_wake_function);
+ bool wait;
+
+ spin_lock_irq(&sem->waiters.lock);
+ /*
+ * Serialize against the wakeup in percpu_up_write(), if we fail
+ * the trylock, the wakeup must see us on the list.
+ */
+ wait = !__percpu_rwsem_trylock(sem, reader);
+ if (wait) {
+ wq_entry.flags |= WQ_FLAG_EXCLUSIVE | reader * WQ_FLAG_CUSTOM;
+ __add_wait_queue_entry_tail(&sem->waiters, &wq_entry);
+ }
+ spin_unlock_irq(&sem->waiters.lock);
+
+ while (wait) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (!smp_load_acquire(&wq_entry.private))
+ break;
+ schedule();
+ }
+ __set_current_state(TASK_RUNNING);
+}
+
+bool __percpu_down_read(struct percpu_rw_semaphore *sem, bool try)
+{
+ if (__percpu_down_read_trylock(sem))
+ return true;
+
+ if (try)
+ return false;
+
+ preempt_enable();
+ percpu_rwsem_wait(sem, /* .reader = */ true);
+ preempt_disable();
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(__percpu_down_read);
#define per_cpu_sum(var) \
({ \
@@ -124,6 +192,8 @@ EXPORT_SYMBOL_GPL(__percpu_up_read);
* zero. If this sum is zero, then it is stable due to the fact that if any
* newly arriving readers increment a given counter, they will immediately
* decrement that same counter.
+ *
+ * Assumes sem->block is set.
*/
static bool readers_active_check(struct percpu_rw_semaphore *sem)
{
@@ -142,32 +212,36 @@ static bool readers_active_check(struct percpu_rw_semaphore *sem)
void percpu_down_write(struct percpu_rw_semaphore *sem)
{
+ might_sleep();
+ rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+
/* Notify readers to take the slow path. */
rcu_sync_enter(&sem->rss);
- down_write(&sem->rw_sem);
+ /*
+ * Try set sem->block; this provides writer-writer exclusion.
+ * Having sem->block set makes new readers block.
+ */
+ if (!__percpu_down_write_trylock(sem))
+ percpu_rwsem_wait(sem, /* .reader = */ false);
+
+ /* smp_mb() implied by __percpu_down_write_trylock() on success -- D matches A */
/*
- * Notify new readers to block; up until now, and thus throughout the
- * longish rcu_sync_enter() above, new readers could still come in.
- */
- WRITE_ONCE(sem->readers_block, 1);
-
- smp_mb(); /* D matches A */
-
- /*
- * If they don't see our writer of readers_block, then we are
- * guaranteed to see their sem->read_count increment, and therefore
- * will wait for them.
+ * If they don't see our store of sem->block, then we are guaranteed to
+ * see their sem->read_count increment, and therefore will wait for
+ * them.
*/
- /* Wait for all now active readers to complete. */
+ /* Wait for all active readers to complete. */
rcuwait_wait_event(&sem->writer, readers_active_check(sem));
}
EXPORT_SYMBOL_GPL(percpu_down_write);
void percpu_up_write(struct percpu_rw_semaphore *sem)
{
+ rwsem_release(&sem->dep_map, 1, _RET_IP_);
+
/*
* Signal the writer is done, no fast path yet.
*
@@ -178,12 +252,12 @@ void percpu_up_write(struct percpu_rw_semaphore *sem)
* Therefore we force it through the slow path which guarantees an
* acquire and thereby guarantees the critical section's consistency.
*/
- smp_store_release(&sem->readers_block, 0);
+ atomic_set_release(&sem->block, 0);
/*
- * Release the write lock, this will allow readers back in the game.
+ * Prod any pending reader/writer to make progress.
*/
- up_write(&sem->rw_sem);
+ __wake_up(&sem->waiters, TASK_NORMAL, 1, sem);
/*
* Once this completes (at least one RCU-sched grace period hence) the
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 7d566aa1ab429..0d11ba11a32ac 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -28,8 +28,6 @@
#include <linux/rwsem.h>
#include <linux/atomic.h>
-#include "rwsem.h"
-
#ifndef CONFIG_PREEMPT_RT
#include "lock_events.h"
@@ -662,8 +660,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem,
unsigned long flags;
bool ret = true;
- BUILD_BUG_ON(!(RWSEM_OWNER_UNKNOWN & RWSEM_NONSPINNABLE));
-
if (need_resched()) {
lockevent_inc(rwsem_opt_fail);
return false;
@@ -1341,7 +1337,7 @@ static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
/*
* lock for reading
*/
-inline void __down_read(struct rw_semaphore *sem)
+static inline void __down_read(struct rw_semaphore *sem)
{
if (!rwsem_read_trylock(sem)) {
rwsem_down_read_slowpath(sem, TASK_UNINTERRUPTIBLE);
@@ -1429,7 +1425,7 @@ static inline int __down_write_trylock(struct rw_semaphore *sem)
/*
* unlock after reading
*/
-inline void __up_read(struct rw_semaphore *sem)
+static inline void __up_read(struct rw_semaphore *sem)
{
long tmp;
diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h
index cd7820880a4f4..e69de29bb2d1d 100644
--- a/kernel/locking/rwsem.h
+++ b/kernel/locking/rwsem.h
@@ -1,12 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-#ifndef __INTERNAL_RWSEM_H
-#define __INTERNAL_RWSEM_H
-#include <linux/rwsem.h>
-
-#ifndef CONFIG_PREEMPT_RT
-extern void __down_read(struct rw_semaphore *sem);
-extern void __up_read(struct rw_semaphore *sem);
-#endif
-
-#endif /* __INTERNAL_RWSEM_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 754f6afb438d8..ea05364619819 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8189,6 +8189,9 @@ static void migrate_disabled_sched(struct task_struct *p)
p->migrate_disable_scheduled = 1;
}
+static DEFINE_PER_CPU(struct cpu_stop_work, migrate_work);
+static DEFINE_PER_CPU(struct migration_arg, migrate_arg);
+
void migrate_enable(void)
{
struct task_struct *p = current;
@@ -8227,22 +8230,24 @@ void migrate_enable(void)
WARN_ON(smp_processor_id() != cpu);
if (!is_cpu_allowed(p, cpu)) {
- struct migration_arg arg = { .task = p };
- struct cpu_stop_work work;
+ struct migration_arg __percpu *arg;
+ struct cpu_stop_work __percpu *work;
struct rq_flags rf;
+ work = this_cpu_ptr(&migrate_work);
+ arg = this_cpu_ptr(&migrate_arg);
+ WARN_ON_ONCE(!arg->done && !work->disabled && work->arg);
+
+ arg->task = p;
+ arg->done = false;
+
rq = task_rq_lock(p, &rf);
update_rq_clock(rq);
- arg.dest_cpu = select_fallback_rq(cpu, p);
+ arg->dest_cpu = select_fallback_rq(cpu, p);
task_rq_unlock(rq, p, &rf);
stop_one_cpu_nowait(task_cpu(p), migration_cpu_stop,
- &arg, &work);
- __schedule(true);
- if (!work.disabled) {
- while (!arg.done)
- cpu_relax();
- }
+ arg, work);
}
out:
diff --git a/localversion-rt b/localversion-rt
index 700c857efd9ba..22746d6390a42 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt8
+-rt9
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 953e106d6cb2d..1e3d9047474ba 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -7043,10 +7043,10 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
mem_cgroup_charge_statistics(memcg, page, PageTransHuge(page),
-nr_entries);
memcg_check_events(memcg, page);
+ local_unlock_irqrestore(event_lock, flags);
if (!mem_cgroup_is_root(memcg))
css_put_many(&memcg->css, nr_entries);
- local_unlock_irqrestore(event_lock, flags);
}
/**
