From 71559291e10da649567b0f753ae58a04bbab7c43 Mon Sep 17 00:00:00 2001
From: hujun5 <hujun5@xiaomi.com>
Date: Fri, 16 Aug 2024 18:48:44 +0800
Subject: [PATCH] sched: replace sync pause with async pause for
 sched_backtrace

Signed-off-by: hujun5 <hujun5@xiaomi.com>
---
 sched/sched/sched_backtrace.c | 88 +++++++++++++++++++++++++++++++----
 1 file changed, 79 insertions(+), 9 deletions(-)

diff --git a/sched/sched/sched_backtrace.c b/sched/sched/sched_backtrace.c
index 6e95b45b51a21..dec02e4854edf 100644
--- a/sched/sched/sched_backtrace.c
+++ b/sched/sched/sched_backtrace.c
@@ -30,6 +30,59 @@
 
 #include "sched.h"
 
+#ifdef CONFIG_ARCH_HAVE_BACKTRACE
+
+/****************************************************************************
+ * Private Type Declarations
+ ****************************************************************************/
+
+#ifdef CONFIG_SMP
+struct backtrace_arg_s
+{
+  pid_t pid;
+  FAR void **buffer;
+  int size;
+  int skip;
+  cpu_set_t saved_affinity;
+  uint16_t saved_flags;
+  bool need_restore;
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static int sched_backtrace_handler(FAR void *cookie)
+{
+  FAR struct backtrace_arg_s *arg = cookie;
+  FAR struct tcb_s *tcb;
+  irqstate_t flags;
+
+  flags = enter_critical_section();
+
+  tcb = nxsched_get_tcb(arg->pid);
+
+  if (!tcb || tcb->task_state == TSTATE_TASK_INVALID ||
+      (tcb->flags & TCB_FLAG_EXIT_PROCESSING) != 0)
+    {
+      /* There is no TCB with this pid or, if there is, it is not a task. */
+
+      leave_critical_section(flags);
+      return -ESRCH;
+    }
+
+  if (arg->need_restore)
+    {
+      tcb->affinity = arg->saved_affinity;
+      tcb->flags = arg->saved_flags;
+    }
+
+  leave_critical_section(flags);
+
+  return up_backtrace(tcb, arg->buffer, arg->size, arg->skip);
+}
+#endif
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -44,7 +97,6 @@
  *
  ****************************************************************************/
 
-#ifdef CONFIG_ARCH_HAVE_BACKTRACE
 int sched_backtrace(pid_t tid, FAR void **buffer, int size, int skip)
 {
   FAR struct tcb_s *tcb = this_task();
@@ -65,18 +117,36 @@ int sched_backtrace(pid_t tid, FAR void **buffer, int size, int skip)
           if (tcb->task_state == TSTATE_TASK_RUNNING &&
               g_nx_initstate != OSINIT_PANIC)
             {
-              up_cpu_pause(tcb->cpu);
+              struct backtrace_arg_s arg;
+
+              if ((tcb->flags & TCB_FLAG_CPU_LOCKED) != 0)
+                {
+                  arg.pid = tcb->pid;
+                  arg.need_restore = false;
+                }
+              else
+                {
+                  arg.pid = tcb->pid;
+                  arg.saved_flags = tcb->flags;
+                  arg.saved_affinity = tcb->affinity;
+                  arg.need_restore = true;
+
+                  tcb->flags |= TCB_FLAG_CPU_LOCKED;
+                  CPU_SET(tcb->cpu, &tcb->affinity);
+                }
+
+              arg.buffer = buffer;
+              arg.size = size;
+              arg.skip = skip;
+              ret = nxsched_smp_call_single(tcb->cpu,
+                                            sched_backtrace_handler,
+                                            &arg, true);
             }
+          else
 #endif
-
-          ret = up_backtrace(tcb, buffer, size, skip);
-#ifdef CONFIG_SMP
-          if (tcb->task_state == TSTATE_TASK_RUNNING &&
-              g_nx_initstate != OSINIT_PANIC)
             {
-              up_cpu_resume(tcb->cpu);
+              ret = up_backtrace(tcb, buffer, size, skip);
             }
-#endif
         }
 
       leave_critical_section(flags);