diff options
Diffstat (limited to 'meta/recipes-kernel/lttng/lttng-modules/0003-fix-sched-tracing-Don-t-re-read-p-state-when-emittin.patch')
| -rw-r--r-- | meta/recipes-kernel/lttng/lttng-modules/0003-fix-sched-tracing-Don-t-re-read-p-state-when-emittin.patch | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/meta/recipes-kernel/lttng/lttng-modules/0003-fix-sched-tracing-Don-t-re-read-p-state-when-emittin.patch b/meta/recipes-kernel/lttng/lttng-modules/0003-fix-sched-tracing-Don-t-re-read-p-state-when-emittin.patch new file mode 100644 index 0000000000..afe514de82 --- /dev/null +++ b/meta/recipes-kernel/lttng/lttng-modules/0003-fix-sched-tracing-Don-t-re-read-p-state-when-emittin.patch @@ -0,0 +1,183 @@ +From 8e52fd71e693619f7a58de2692e59f0c826e9988 Mon Sep 17 00:00:00 2001 +From: Michael Jeanson <mjeanson@efficios.com> +Date: Mon, 4 Apr 2022 13:52:57 -0400 +Subject: [PATCH 03/10] fix: sched/tracing: Don't re-read p->state when + emitting sched_switch event (v5.18) + +See upstream commit : + + commit fa2c3254d7cfff5f7a916ab928a562d1165f17bb + Author: Valentin Schneider <valentin.schneider@arm.com> + Date: Thu Jan 20 16:25:19 2022 +0000 + + sched/tracing: Don't re-read p->state when emitting sched_switch event + + As of commit + + c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu") + + the following sequence becomes possible: + + p->__state = TASK_INTERRUPTIBLE; + __schedule() + deactivate_task(p); + ttwu() + READ !p->on_rq + p->__state=TASK_WAKING + trace_sched_switch() + __trace_sched_switch_state() + task_state_index() + return 0; + + TASK_WAKING isn't in TASK_REPORT, so the task appears as TASK_RUNNING in + the trace event. + + Prevent this by pushing the value read from __schedule() down the trace + event. + +Upstream-Status: Backport + +Change-Id: I46743cd006be4b4d573cae2d77df7d6d16744d04 +Signed-off-by: Michael Jeanson <mjeanson@efficios.com> +Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> +--- + include/instrumentation/events/sched.h | 88 +++++++++++++++++++++++--- + 1 file changed, 78 insertions(+), 10 deletions(-) + +diff --git a/include/instrumentation/events/sched.h b/include/instrumentation/events/sched.h +index 91953a6f..339bec94 100644 +--- a/include/instrumentation/events/sched.h ++++ b/include/instrumentation/events/sched.h +@@ -20,7 +20,37 @@ + #ifndef _TRACE_SCHED_DEF_ + #define _TRACE_SCHED_DEF_ + +-#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,15,0)) ++#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,18,0)) ++ ++static inline long __trace_sched_switch_state(bool preempt, ++ unsigned int prev_state, ++ struct task_struct *p) ++{ ++ unsigned int state; ++ ++#ifdef CONFIG_SCHED_DEBUG ++ BUG_ON(p != current); ++#endif /* CONFIG_SCHED_DEBUG */ ++ ++ /* ++ * Preemption ignores task state, therefore preempted tasks are always ++ * RUNNING (we will not have dequeued if state != RUNNING). ++ */ ++ if (preempt) ++ return TASK_REPORT_MAX; ++ ++ /* ++ * task_state_index() uses fls() and returns a value from 0-8 range. ++ * Decrement it by 1 (except TASK_RUNNING state i.e 0) before using ++ * it for left shift operation to get the correct task->state ++ * mapping. ++ */ ++ state = __task_state_index(prev_state, p->exit_state); ++ ++ return state ? (1 << (state - 1)) : state; ++} ++ ++#elif (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,15,0)) + + static inline long __trace_sched_switch_state(bool preempt, struct task_struct *p) + { +@@ -321,43 +351,81 @@ LTTNG_TRACEPOINT_EVENT_INSTANCE(sched_wakeup_template, sched_wakeup_new, + /* + * Tracepoint for task switches, performed by the scheduler: + */ ++ ++#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,18,0)) + LTTNG_TRACEPOINT_EVENT(sched_switch, + +-#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,4,0)) + TP_PROTO(bool preempt, +- struct task_struct *prev, +- struct task_struct *next), ++ unsigned int prev_state, ++ struct task_struct *prev, ++ struct task_struct *next), + +- TP_ARGS(preempt, prev, next), ++ TP_ARGS(preempt, prev_state, prev, next), ++ ++ TP_FIELDS( ++ ctf_array_text(char, prev_comm, prev->comm, TASK_COMM_LEN) ++ ctf_integer(pid_t, prev_tid, prev->pid) ++ ctf_integer(int, prev_prio, prev->prio - MAX_RT_PRIO) ++#ifdef CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM ++ ctf_enum(task_state, long, prev_state, __trace_sched_switch_state(preempt, prev_state, prev)) + #else +- TP_PROTO(struct task_struct *prev, ++ ctf_integer(long, prev_state, __trace_sched_switch_state(preempt, prev_state, prev)) ++#endif ++ ctf_array_text(char, next_comm, next->comm, TASK_COMM_LEN) ++ ctf_integer(pid_t, next_tid, next->pid) ++ ctf_integer(int, next_prio, next->prio - MAX_RT_PRIO) ++ ) ++) ++ ++#elif (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,4,0)) ++ ++LTTNG_TRACEPOINT_EVENT(sched_switch, ++ ++ TP_PROTO(bool preempt, ++ struct task_struct *prev, + struct task_struct *next), + +- TP_ARGS(prev, next), +-#endif /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,4,0)) */ ++ TP_ARGS(preempt, prev, next), + + TP_FIELDS( + ctf_array_text(char, prev_comm, prev->comm, TASK_COMM_LEN) + ctf_integer(pid_t, prev_tid, prev->pid) + ctf_integer(int, prev_prio, prev->prio - MAX_RT_PRIO) +-#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,4,0)) + #ifdef CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM + ctf_enum(task_state, long, prev_state, __trace_sched_switch_state(preempt, prev)) + #else + ctf_integer(long, prev_state, __trace_sched_switch_state(preempt, prev)) + #endif ++ ctf_array_text(char, next_comm, next->comm, TASK_COMM_LEN) ++ ctf_integer(pid_t, next_tid, next->pid) ++ ctf_integer(int, next_prio, next->prio - MAX_RT_PRIO) ++ ) ++) ++ + #else ++ ++LTTNG_TRACEPOINT_EVENT(sched_switch, ++ ++ TP_PROTO(struct task_struct *prev, ++ struct task_struct *next), ++ ++ TP_ARGS(prev, next), ++ ++ TP_FIELDS( ++ ctf_array_text(char, prev_comm, prev->comm, TASK_COMM_LEN) ++ ctf_integer(pid_t, prev_tid, prev->pid) ++ ctf_integer(int, prev_prio, prev->prio - MAX_RT_PRIO) + #ifdef CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM + ctf_enum(task_state, long, prev_state, __trace_sched_switch_state(prev)) + #else + ctf_integer(long, prev_state, __trace_sched_switch_state(prev)) +-#endif + #endif + ctf_array_text(char, next_comm, next->comm, TASK_COMM_LEN) + ctf_integer(pid_t, next_tid, next->pid) + ctf_integer(int, next_prio, next->prio - MAX_RT_PRIO) + ) + ) ++#endif + + /* + * Tracepoint for a task being migrated: +-- +2.19.1 + |