From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/kernel/sched/wait.c | 72 +++++++++++++++++++++++------------
1 files changed, 47 insertions(+), 25 deletions(-)
diff --git a/kernel/kernel/sched/wait.c b/kernel/kernel/sched/wait.c
index 4503a5d..c4f324a 100644
--- a/kernel/kernel/sched/wait.c
+++ b/kernel/kernel/sched/wait.c
@@ -1,9 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic waiting primitives.
*
* (C) 2004 Nadia Yvette Chambers, Oracle
*/
#include "sched.h"
+#include <trace/hooks/sched.h>
void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *key)
{
@@ -117,16 +119,12 @@
bookmark.func = NULL;
INIT_LIST_HEAD(&bookmark.entry);
- spin_lock_irqsave(&wq_head->lock, flags);
- nr_exclusive = __wake_up_common(wq_head, mode, nr_exclusive, wake_flags, key, &bookmark);
- spin_unlock_irqrestore(&wq_head->lock, flags);
-
- while (bookmark.flags & WQ_FLAG_BOOKMARK) {
+ do {
spin_lock_irqsave(&wq_head->lock, flags);
nr_exclusive = __wake_up_common(wq_head, mode, nr_exclusive,
wake_flags, key, &bookmark);
spin_unlock_irqrestore(&wq_head->lock, flags);
- }
+ } while (bookmark.flags & WQ_FLAG_BOOKMARK);
}
/**
@@ -172,7 +170,6 @@
* __wake_up_sync_key - wake up threads blocked on a waitqueue.
* @wq_head: the waitqueue
* @mode: which threads
- * @nr_exclusive: how many wake-one or wake-many threads to wake up
* @key: opaque value to be passed to wakeup targets
*
* The sync wakeup differs that the waker knows that it will schedule
@@ -186,26 +183,47 @@
* accessing the task state.
*/
void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode,
- int nr_exclusive, void *key)
+ void *key)
{
- int wake_flags = 1; /* XXX WF_SYNC */
+ int wake_flags = WF_SYNC;
if (unlikely(!wq_head))
return;
- if (unlikely(nr_exclusive != 1))
- wake_flags = 0;
-
- __wake_up_common_lock(wq_head, mode, nr_exclusive, wake_flags, key);
+ trace_android_vh_set_wake_flags(&wake_flags, &mode);
+ __wake_up_common_lock(wq_head, mode, 1, wake_flags, key);
}
EXPORT_SYMBOL_GPL(__wake_up_sync_key);
+
+/**
+ * __wake_up_locked_sync_key - wake up a thread blocked on a locked waitqueue.
+ * @wq_head: the waitqueue
+ * @mode: which threads
+ * @key: opaque value to be passed to wakeup targets
+ *
+ * The sync wakeup differs in that the waker knows that it will schedule
+ * away soon, so while the target thread will be woken up, it will not
+ * be migrated to another CPU - ie. the two threads are 'synchronized'
+ * with each other. This can prevent needless bouncing between CPUs.
+ *
+ * On UP it can prevent extra preemption.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ */
+void __wake_up_locked_sync_key(struct wait_queue_head *wq_head,
+ unsigned int mode, void *key)
+{
+ __wake_up_common(wq_head, mode, 1, WF_SYNC, key, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked_sync_key);
/*
* __wake_up_sync - see __wake_up_sync_key()
*/
-void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr_exclusive)
+void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode)
{
- __wake_up_sync_key(wq_head, mode, nr_exclusive, NULL);
+ __wake_up_sync_key(wq_head, mode, NULL);
}
EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
@@ -242,17 +260,22 @@
}
EXPORT_SYMBOL(prepare_to_wait);
-void
+/* Returns true if we are the first waiter in the queue, false otherwise. */
+bool
prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
{
unsigned long flags;
+ bool was_empty = false;
wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
spin_lock_irqsave(&wq_head->lock, flags);
- if (list_empty(&wq_entry->entry))
+ if (list_empty(&wq_entry->entry)) {
+ was_empty = list_empty(&wq_head->head);
__add_wait_queue_entry_tail(wq_head, wq_entry);
+ }
set_current_state(state);
spin_unlock_irqrestore(&wq_head->lock, flags);
+ return was_empty;
}
EXPORT_SYMBOL(prepare_to_wait_exclusive);
@@ -271,7 +294,7 @@
long ret = 0;
spin_lock_irqsave(&wq_head->lock, flags);
- if (unlikely(signal_pending_state(state, current))) {
+ if (signal_pending_state(state, current)) {
/*
* Exclusive waiter must not fail if it was selected by wakeup,
* it should "consume" the condition we were waiting for.
@@ -377,13 +400,13 @@
}
EXPORT_SYMBOL(finish_wait);
-int __sched autoremove_wake_function(struct wait_queue_entry *wq_entry,
- unsigned int mode, int sync, void *key)
+__sched int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned int mode,
+ int sync, void *key)
{
int ret = default_wake_function(wq_entry, mode, sync, key);
if (ret)
- list_del_init(&wq_entry->entry);
+ list_del_init_careful(&wq_entry->entry);
return ret;
}
@@ -414,8 +437,7 @@
* } smp_mb(); // C
* remove_wait_queue(&wq_head, &wait); wq_entry->flags |= WQ_FLAG_WOKEN;
*/
-long __sched wait_woken(struct wait_queue_entry *wq_entry, unsigned int mode,
- long timeout)
+__sched long wait_woken(struct wait_queue_entry *wq_entry, unsigned int mode, long timeout)
{
/*
* The below executes an smp_mb(), which matches with the full barrier
@@ -440,8 +462,8 @@
}
EXPORT_SYMBOL(wait_woken);
-int __sched woken_wake_function(struct wait_queue_entry *wq_entry,
- unsigned int mode, int sync, void *key)
+__sched int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned int mode,
+ int sync, void *key)
{
/* Pairs with the smp_store_mb() in wait_woken(). */
smp_mb(); /* C */
--
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