diff options
Diffstat (limited to 'features/rt/tasklets-Replace-barrier-with-cpu_relax-in-tasklet_u.patch')
| -rw-r--r-- | features/rt/tasklets-Replace-barrier-with-cpu_relax-in-tasklet_u.patch | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/features/rt/tasklets-Replace-barrier-with-cpu_relax-in-tasklet_u.patch b/features/rt/tasklets-Replace-barrier-with-cpu_relax-in-tasklet_u.patch new file mode 100644 index 00000000..1a86c472 --- /dev/null +++ b/features/rt/tasklets-Replace-barrier-with-cpu_relax-in-tasklet_u.patch @@ -0,0 +1,34 @@ +From 5c591a9398a637929ea3593614fadff800e6009f Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Tue, 9 Mar 2021 09:42:04 +0100 +Subject: [PATCH 041/191] tasklets: Replace barrier() with cpu_relax() in + tasklet_unlock_wait() + +A barrier() in a tight loop which waits for something to happen on a remote +CPU is a pointless exercise. Replace it with cpu_relax() which allows HT +siblings to make progress. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + include/linux/interrupt.h | 3 ++- + 1 file changed, 2 insertions(+), 1 deletion(-) + +diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h +index 967e25767153..b4cf773638dc 100644 +--- a/include/linux/interrupt.h ++++ b/include/linux/interrupt.h +@@ -668,7 +668,8 @@ static inline void tasklet_unlock(struct tasklet_struct *t) + + static inline void tasklet_unlock_wait(struct tasklet_struct *t) + { +- while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); } ++ while (test_bit(TASKLET_STATE_RUN, &t->state)) ++ cpu_relax(); + } + #else + #define tasklet_trylock(t) 1 +-- +2.19.1 + |