diff options
Diffstat (limited to 'features/rt/tasklets-Replace-spin-wait-in-tasklet_unlock_wait.patch')
| -rw-r--r-- | features/rt/tasklets-Replace-spin-wait-in-tasklet_unlock_wait.patch | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/features/rt/tasklets-Replace-spin-wait-in-tasklet_unlock_wait.patch b/features/rt/tasklets-Replace-spin-wait-in-tasklet_unlock_wait.patch deleted file mode 100644 index edca165f..00000000 --- a/features/rt/tasklets-Replace-spin-wait-in-tasklet_unlock_wait.patch +++ /dev/null @@ -1,89 +0,0 @@ -From 9c90471b76134571fa2dfddb7423d48c521146ab Mon Sep 17 00:00:00 2001 -From: Peter Zijlstra <peterz@infradead.org> -Date: Tue, 9 Mar 2021 09:42:08 +0100 -Subject: [PATCH 045/191] tasklets: Replace spin wait in tasklet_unlock_wait() - -tasklet_unlock_wait() spin waits for TASKLET_STATE_RUN to be cleared. This -is wasting CPU cycles in a tight loop which is especially painful in a -guest when the CPU running the tasklet is scheduled out. - -tasklet_unlock_wait() is invoked from tasklet_kill() which is used in -teardown paths and not performance critical at all. Replace the spin wait -with wait_var_event(). - -There are no users of tasklet_unlock_wait() which are invoked from atomic -contexts. The usage in tasklet_disable() has been replaced temporarily with -the spin waiting variant until the atomic users are fixed up and will be -converted to the sleep wait variant later. - -Signed-off-by: Peter Zijlstra <peterz@infradead.org> -Signed-off-by: Thomas Gleixner <tglx@linutronix.de> -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> ---- - include/linux/interrupt.h | 13 ++----------- - kernel/softirq.c | 18 ++++++++++++++++++ - 2 files changed, 20 insertions(+), 11 deletions(-) - -diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h -index f0b82429950c..ee3ce4f852b7 100644 ---- a/include/linux/interrupt.h -+++ b/include/linux/interrupt.h -@@ -660,17 +660,8 @@ static inline int tasklet_trylock(struct tasklet_struct *t) - return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state); - } - --static inline void tasklet_unlock(struct tasklet_struct *t) --{ -- smp_mb__before_atomic(); -- clear_bit(TASKLET_STATE_RUN, &(t)->state); --} -- --static inline void tasklet_unlock_wait(struct tasklet_struct *t) --{ -- while (test_bit(TASKLET_STATE_RUN, &t->state)) -- cpu_relax(); --} -+void tasklet_unlock(struct tasklet_struct *t); -+void tasklet_unlock_wait(struct tasklet_struct *t); - - /* - * Do not use in new code. Waiting for tasklets from atomic contexts is -diff --git a/kernel/softirq.c b/kernel/softirq.c -index 9908ec4a9bfe..7cd63df59e1c 100644 ---- a/kernel/softirq.c -+++ b/kernel/softirq.c -@@ -25,6 +25,7 @@ - #include <linux/smpboot.h> - #include <linux/tick.h> - #include <linux/irq.h> -+#include <linux/wait_bit.h> - - #include <asm/softirq_stack.h> - -@@ -621,6 +622,23 @@ void tasklet_kill(struct tasklet_struct *t) - } - EXPORT_SYMBOL(tasklet_kill); - -+#ifdef CONFIG_SMP -+void tasklet_unlock(struct tasklet_struct *t) -+{ -+ smp_mb__before_atomic(); -+ clear_bit(TASKLET_STATE_RUN, &t->state); -+ smp_mb__after_atomic(); -+ wake_up_var(&t->state); -+} -+EXPORT_SYMBOL_GPL(tasklet_unlock); -+ -+void tasklet_unlock_wait(struct tasklet_struct *t) -+{ -+ wait_var_event(&t->state, !test_bit(TASKLET_STATE_RUN, &t->state)); -+} -+EXPORT_SYMBOL_GPL(tasklet_unlock_wait); -+#endif -+ - void __init softirq_init(void) - { - int cpu; --- -2.19.1 - |