6.6-stable review patch. If anyone has any objections, please let me know.
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From: Elliot Berman quic_eberman@quicinc.com
commit fbaa6a181a4b1886cbf4214abdf9a2df68471510 upstream.
In preparation for freezer to also use saved_state, remove the CONFIG_PREEMPT_RT compilation guard around saved_state.
On the arm64 platform I tested which did not have CONFIG_PREEMPT_RT, there was no statistically significant deviation by applying this patch.
Test methodology:
perf bench sched message -g 40 -l 40
Signed-off-by: Elliot Berman quic_eberman@quicinc.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Chen Ridong chenridong@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/sched.h | 2 -- kernel/sched/core.c | 10 ++-------- 2 files changed, 2 insertions(+), 10 deletions(-)
--- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -753,10 +753,8 @@ struct task_struct { #endif unsigned int __state;
-#ifdef CONFIG_PREEMPT_RT /* saved state for "spinlock sleepers" */ unsigned int saved_state; -#endif
/* * This begins the randomizable portion of task_struct. Only --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2238,17 +2238,15 @@ int __task_state_match(struct task_struc if (READ_ONCE(p->__state) & state) return 1;
-#ifdef CONFIG_PREEMPT_RT if (READ_ONCE(p->saved_state) & state) return -1; -#endif + return 0; }
static __always_inline int task_state_match(struct task_struct *p, unsigned int state) { -#ifdef CONFIG_PREEMPT_RT int match;
/* @@ -2260,9 +2258,6 @@ int task_state_match(struct task_struct raw_spin_unlock_irq(&p->pi_lock);
return match; -#else - return __task_state_match(p, state); -#endif }
/* @@ -4059,7 +4054,6 @@ bool ttwu_state_match(struct task_struct
*success = !!(match = __task_state_match(p, state));
-#ifdef CONFIG_PREEMPT_RT /* * Saved state preserves the task state across blocking on * an RT lock. If the state matches, set p::saved_state to @@ -4075,7 +4069,7 @@ bool ttwu_state_match(struct task_struct */ if (match < 0) p->saved_state = TASK_RUNNING; -#endif + return match > 0; }