#ifndef _LINUX_IRQ_WORK_H
#define _LINUX_IRQ_WORK_H
-#include <linux/llist.h>
+#include <linux/smp_types.h>
/*
* An entry can be in one of four states:
* busy NULL, 2 -> {free, claimed} : callback in progress, can be claimed
*/
-/* flags share CSD_FLAG_ space */
-
-#define IRQ_WORK_PENDING BIT(0)
-#define IRQ_WORK_BUSY BIT(1)
-
-/* Doesn't want IPI, wait for tick: */
-#define IRQ_WORK_LAZY BIT(2)
-/* Run hard IRQ context, even on RT */
-#define IRQ_WORK_HARD_IRQ BIT(3)
-
-#define IRQ_WORK_CLAIMED (IRQ_WORK_PENDING | IRQ_WORK_BUSY)
-
-/*
- * structure shares layout with single_call_data_t.
- */
struct irq_work {
- struct llist_node llnode;
- atomic_t flags;
+ union {
+ struct __call_single_node node;
+ struct {
+ struct llist_node llnode;
+ atomic_t flags;
+ };
+ };
void (*func)(struct irq_work *);
};
unsigned int ptrace;
#ifdef CONFIG_SMP
- struct {
- struct llist_node wake_entry;
- unsigned int wake_entry_type;
- };
int on_cpu;
+ struct __call_single_node wake_entry;
#ifdef CONFIG_THREAD_INFO_IN_TASK
/* Current CPU: */
unsigned int cpu;
#include <linux/list.h>
#include <linux/cpumask.h>
#include <linux/init.h>
-#include <linux/llist.h>
+#include <linux/smp_types.h>
typedef void (*smp_call_func_t)(void *info);
typedef bool (*smp_cond_func_t)(int cpu, void *info);
-enum {
- CSD_FLAG_LOCK = 0x01,
-
- /* IRQ_WORK_flags */
-
- CSD_TYPE_ASYNC = 0x00,
- CSD_TYPE_SYNC = 0x10,
- CSD_TYPE_IRQ_WORK = 0x20,
- CSD_TYPE_TTWU = 0x30,
- CSD_FLAG_TYPE_MASK = 0xF0,
-};
-
/*
* structure shares (partial) layout with struct irq_work
*/
struct __call_single_data {
- struct llist_node llist;
- unsigned int flags;
+ union {
+ struct __call_single_node node;
+ struct {
+ struct llist_node llist;
+ unsigned int flags;
+ };
+ };
smp_call_func_t func;
void *info;
};
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_SMP_TYPES_H
+#define __LINUX_SMP_TYPES_H
+
+#include <linux/llist.h>
+
+enum {
+ CSD_FLAG_LOCK = 0x01,
+
+ IRQ_WORK_PENDING = 0x01,
+ IRQ_WORK_BUSY = 0x02,
+ IRQ_WORK_LAZY = 0x04, /* No IPI, wait for tick */
+ IRQ_WORK_HARD_IRQ = 0x08, /* IRQ context on PREEMPT_RT */
+
+ IRQ_WORK_CLAIMED = (IRQ_WORK_PENDING | IRQ_WORK_BUSY),
+
+ CSD_TYPE_ASYNC = 0x00,
+ CSD_TYPE_SYNC = 0x10,
+ CSD_TYPE_IRQ_WORK = 0x20,
+ CSD_TYPE_TTWU = 0x30,
+
+ CSD_FLAG_TYPE_MASK = 0xF0,
+};
+
+/*
+ * struct __call_single_node is the primary type on
+ * smp.c:call_single_queue.
+ *
+ * flush_smp_call_function_queue() only reads the type from
+ * __call_single_node::u_flags as a regular load, the above
+ * (anonymous) enum defines all the bits of this word.
+ *
+ * Other bits are not modified until the type is known.
+ *
+ * CSD_TYPE_SYNC/ASYNC:
+ * struct {
+ * struct llist_node node;
+ * unsigned int flags;
+ * smp_call_func_t func;
+ * void *info;
+ * };
+ *
+ * CSD_TYPE_IRQ_WORK:
+ * struct {
+ * struct llist_node node;
+ * atomic_t flags;
+ * void (*func)(struct irq_work *);
+ * };
+ *
+ * CSD_TYPE_TTWU:
+ * struct {
+ * struct llist_node node;
+ * unsigned int flags;
+ * };
+ *
+ */
+
+struct __call_single_node {
+ struct llist_node llist;
+ union {
+ unsigned int u_flags;
+ atomic_t a_flags;
+ };
+};
+
+#endif /* __LINUX_SMP_TYPES_H */
rq_lock_irqsave(rq, &rf);
update_rq_clock(rq);
- llist_for_each_entry_safe(p, t, llist, wake_entry) {
+ llist_for_each_entry_safe(p, t, llist, wake_entry.llist) {
if (WARN_ON_ONCE(p->on_cpu))
smp_cond_load_acquire(&p->on_cpu, !VAL);
p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
WRITE_ONCE(rq->ttwu_pending, 1);
- __smp_call_single_queue(cpu, &p->wake_entry);
+ __smp_call_single_queue(cpu, &p->wake_entry.llist);
}
void wake_up_if_idle(int cpu)
#endif
init_numa_balancing(clone_flags, p);
#ifdef CONFIG_SMP
- p->wake_entry_type = CSD_TYPE_TTWU;
+ p->wake_entry.u_flags = CSD_TYPE_TTWU;
#endif
}
{
int num_nodes, num_cpus;
- /*
- * Ensure struct irq_work layout matches so that
- * flush_smp_call_function_queue() can do horrible things.
- */
- BUILD_BUG_ON(offsetof(struct irq_work, llnode) !=
- offsetof(struct __call_single_data, llist));
- BUILD_BUG_ON(offsetof(struct irq_work, func) !=
- offsetof(struct __call_single_data, func));
- BUILD_BUG_ON(offsetof(struct irq_work, flags) !=
- offsetof(struct __call_single_data, flags));
-
- /*
- * Assert the CSD_TYPE_TTWU layout is similar enough
- * for task_struct to be on the @call_single_queue.
- */
- BUILD_BUG_ON(offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) !=
- offsetof(struct __call_single_data, flags) - offsetof(struct __call_single_data, llist));
-
idle_threads_init();
cpuhp_threads_init();