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-rw-r--r--include/linux/bit_spinlock.h2
-rw-r--r--include/linux/hardirq.h4
-rw-r--r--include/linux/pagemap.h4
-rw-r--r--include/linux/preempt.h26
-rw-r--r--include/linux/rcupdate.h12
-rw-r--r--include/linux/sched.h2
-rw-r--r--kernel/Kconfig.preempt3
-rw-r--r--kernel/sched.c2
8 files changed, 33 insertions, 22 deletions
diff --git a/include/linux/bit_spinlock.h b/include/linux/bit_spinlock.h
index b4326bfa684f..564d997e2168 100644
--- a/include/linux/bit_spinlock.h
+++ b/include/linux/bit_spinlock.h
@@ -88,7 +88,7 @@ static inline int bit_spin_is_locked(int bitnum, unsigned long *addr)
{
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
return test_bit(bitnum, addr);
-#elif defined CONFIG_PREEMPT
+#elif defined CONFIG_PREEMPT_COUNT
return preempt_count();
#else
return 1;
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index ba362171e8ae..f743883f769e 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -93,7 +93,7 @@
*/
#define in_nmi() (preempt_count() & NMI_MASK)
-#if defined(CONFIG_PREEMPT)
+#if defined(CONFIG_PREEMPT_COUNT)
# define PREEMPT_CHECK_OFFSET 1
#else
# define PREEMPT_CHECK_OFFSET 0
@@ -115,7 +115,7 @@
#define in_atomic_preempt_off() \
((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
# define preemptible() (preempt_count() == 0 && !irqs_disabled())
# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
#else
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 716875e53520..8e38d4c140ff 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -134,7 +134,7 @@ static inline int page_cache_get_speculative(struct page *page)
VM_BUG_ON(in_interrupt());
#if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
-# ifdef CONFIG_PREEMPT
+# ifdef CONFIG_PREEMPT_COUNT
VM_BUG_ON(!in_atomic());
# endif
/*
@@ -172,7 +172,7 @@ static inline int page_cache_add_speculative(struct page *page, int count)
VM_BUG_ON(in_interrupt());
#if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
-# ifdef CONFIG_PREEMPT
+# ifdef CONFIG_PREEMPT_COUNT
VM_BUG_ON(!in_atomic());
# endif
VM_BUG_ON(page_count(page) == 0);
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 2e681d9555bd..58969b2a8a82 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -27,6 +27,21 @@
asmlinkage void preempt_schedule(void);
+#define preempt_check_resched() \
+do { \
+ if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
+ preempt_schedule(); \
+} while (0)
+
+#else /* !CONFIG_PREEMPT */
+
+#define preempt_check_resched() do { } while (0)
+
+#endif /* CONFIG_PREEMPT */
+
+
+#ifdef CONFIG_PREEMPT_COUNT
+
#define preempt_disable() \
do { \
inc_preempt_count(); \
@@ -39,12 +54,6 @@ do { \
dec_preempt_count(); \
} while (0)
-#define preempt_check_resched() \
-do { \
- if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
- preempt_schedule(); \
-} while (0)
-
#define preempt_enable() \
do { \
preempt_enable_no_resched(); \
@@ -80,18 +89,17 @@ do { \
preempt_check_resched(); \
} while (0)
-#else
+#else /* !CONFIG_PREEMPT_COUNT */
#define preempt_disable() do { } while (0)
#define preempt_enable_no_resched() do { } while (0)
#define preempt_enable() do { } while (0)
-#define preempt_check_resched() do { } while (0)
#define preempt_disable_notrace() do { } while (0)
#define preempt_enable_no_resched_notrace() do { } while (0)
#define preempt_enable_notrace() do { } while (0)
-#endif
+#endif /* CONFIG_PREEMPT_COUNT */
#ifdef CONFIG_PREEMPT_NOTIFIERS
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 99f9aa7c2804..8f4f881a0ad8 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -239,7 +239,7 @@ extern int rcu_read_lock_bh_held(void);
* Check debug_lockdep_rcu_enabled() to prevent false positives during boot
* and while lockdep is disabled.
*/
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
static inline int rcu_read_lock_sched_held(void)
{
int lockdep_opinion = 0;
@@ -250,12 +250,12 @@ static inline int rcu_read_lock_sched_held(void)
lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
return lockdep_opinion || preempt_count() != 0 || irqs_disabled();
}
-#else /* #ifdef CONFIG_PREEMPT */
+#else /* #ifdef CONFIG_PREEMPT_COUNT */
static inline int rcu_read_lock_sched_held(void)
{
return 1;
}
-#endif /* #else #ifdef CONFIG_PREEMPT */
+#endif /* #else #ifdef CONFIG_PREEMPT_COUNT */
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
@@ -276,17 +276,17 @@ static inline int rcu_read_lock_bh_held(void)
return 1;
}
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
static inline int rcu_read_lock_sched_held(void)
{
return preempt_count() != 0 || irqs_disabled();
}
-#else /* #ifdef CONFIG_PREEMPT */
+#else /* #ifdef CONFIG_PREEMPT_COUNT */
static inline int rcu_read_lock_sched_held(void)
{
return 1;
}
-#endif /* #else #ifdef CONFIG_PREEMPT */
+#endif /* #else #ifdef CONFIG_PREEMPT_COUNT */
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 483c1ed5bc4d..4ecd5cbe7e24 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2502,7 +2502,7 @@ extern int _cond_resched(void);
extern int __cond_resched_lock(spinlock_t *lock);
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
#define PREEMPT_LOCK_OFFSET PREEMPT_OFFSET
#else
#define PREEMPT_LOCK_OFFSET 0
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index bf987b95b356..24e7cb0ba26a 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -35,6 +35,7 @@ config PREEMPT_VOLUNTARY
config PREEMPT
bool "Preemptible Kernel (Low-Latency Desktop)"
+ select PREEMPT_COUNT
help
This option reduces the latency of the kernel by making
all kernel code (that is not executing in a critical section)
@@ -52,3 +53,5 @@ config PREEMPT
endchoice
+config PREEMPT_COUNT
+ bool \ No newline at end of file
diff --git a/kernel/sched.c b/kernel/sched.c
index 01d9536aaa8e..90ad7cf2b290 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2843,7 +2843,7 @@ void sched_fork(struct task_struct *p)
#if defined(CONFIG_SMP)
p->on_cpu = 0;
#endif
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
/* Want to start with kernel preemption disabled. */
task_thread_info(p)->preempt_count = 1;
#endif
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.