From: Gabriel-Andrew Pollo-Guilbert <gabriel.pollo-guilbert@efficios.com>
Date: Mon, 16 Sep 2019 17:57:38 +0000 (-0400)
Subject: Fix: update sched prev_state instrumentation for upstream kernel
X-Git-Tag: v2.11.0-rc7~3
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=57069e5d5b1cdf9785c266bbec31bc80ee552bcc;p=lttng-modules.git

Fix: update sched prev_state instrumentation for upstream kernel

Introduced in upstream Linux kernel 4.14.

    commit efb40f588b4370ffaeffafbd50f6ff213d954254
    Author: Peter Zijlstra <peterz@infradead.org>
    Date:   Fri Sep 22 18:19:53 2017 +0200

        sched/tracing: Fix trace_sched_switch task-state printing

Introduced in upstream Linux kernel 4.15.
Backported in 13f12749af15 (4.14.64).

    commit 3f5fe9fef5b2da06b6319fab8123056da5217c3f
    Author: Thomas Gleixner <tglx@linutronix.de>
    Date:   Wed Nov 22 13:05:48 2017 +0100

        sched/debug: Fix task state recording/printout

Introduced in upstream Linux kernel 4.20.
Backported in e1e5fa73e466 (4.14.102) and fd8152818f11 (4.19.9).

    commit 3054426dc68e5d63aa6a6e9b91ac4ec78e3f3805
    Author: Pavankumar Kondeti <pkondeti@codeaurora.org>
    Date:   Tue Oct 30 12:24:33 2018 +0530

        sched, trace: Fix prev_state output in sched_switch tracepoint

Signed-off-by: Gabriel-Andrew Pollo-Guilbert <gabriel.pollo-guilbert@efficios.com>
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/instrumentation/events/lttng-module/sched.h b/instrumentation/events/lttng-module/sched.h
index 550ce2f2..95bf13cc 100644
--- a/instrumentation/events/lttng-module/sched.h
+++ b/instrumentation/events/lttng-module/sched.h
@@ -25,7 +25,63 @@
 #ifndef _TRACE_SCHED_DEF_
 #define _TRACE_SCHED_DEF_
 
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,0))
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,15,0))
+
+static inline long __trace_sched_switch_state(bool preempt, 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(p);
+
+        return state ? (1 << (state - 1)) : state;
+}
+
+#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(4,14,0))
+
+static inline long __trace_sched_switch_state(bool preempt, 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;
+
+        /*
+         * __get_task_state() 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 = __get_task_state(p);
+
+        return state ? (1 << (state - 1)) : state;
+}
+
+#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,0))
 
 static inline long __trace_sched_switch_state(bool preempt, struct task_struct *p)
 {