From 4b6ae5dc1048fa55e1c88c3d62b10ae94594ab16 Mon Sep 17 00:00:00 2001
From: Elena Frank <elena.frank@protonmail.com>
Date: Sat, 7 Sep 2024 13:31:57 +0200
Subject: [PATCH] refactor(threads): move `sched`-independent code to `Threads`

---
 examples/threading-multicore/laze.yml    |  1 +
 src/riot-rs-threads/src/arch/cortex_m.rs | 41 +++---------------------
 src/riot-rs-threads/src/lib.rs           | 40 +++++++++++++++++++++++
 3 files changed, 45 insertions(+), 37 deletions(-)

diff --git a/examples/threading-multicore/laze.yml b/examples/threading-multicore/laze.yml
index d647c3323..1c02609e1 100644
--- a/examples/threading-multicore/laze.yml
+++ b/examples/threading-multicore/laze.yml
@@ -2,3 +2,4 @@ apps:
   - name: threading-multicore
     selects:
       - ?release
+      - executor-thread
diff --git a/src/riot-rs-threads/src/arch/cortex_m.rs b/src/riot-rs-threads/src/arch/cortex_m.rs
index 02642c7f9..035af797b 100644
--- a/src/riot-rs-threads/src/arch/cortex_m.rs
+++ b/src/riot-rs-threads/src/arch/cortex_m.rs
@@ -3,7 +3,7 @@ use core::arch::asm;
 use core::ptr::write_volatile;
 use cortex_m::peripheral::{scb::SystemHandler, SCB};
 
-use crate::{cleanup, ThreadId, THREADS};
+use crate::{cleanup, THREADS};
 
 #[cfg(not(any(armv6m, armv7m, armv8m)))]
 compile_error!("no supported ARM variant selected");
@@ -161,30 +161,6 @@ unsafe extern "C" fn PendSV() {
     };
 }
 
-fn get_next_pid(threads: &mut crate::Threads) -> Option<ThreadId> {
-    #[cfg(not(feature = "multicore"))]
-    {
-        return threads.runqueue.get_next();
-    }
-    #[cfg(feature = "multicore")]
-    #[cfg(not(feature = "core-affinity"))]
-    {
-        return threads.runqueue.pop_next();
-    }
-    #[cfg(feature = "core-affinity")]
-    {
-        let (mut next, prio) = threads.runqueue.peek_next()?;
-        if !threads.is_affine_to_curr_core(next) {
-            let iter = threads.runqueue.iter_from(next, prio);
-            next = iter
-                .filter(|pid| threads.is_affine_to_curr_core(*pid))
-                .next()?
-        }
-        threads.runqueue.del(next);
-        return Some(next);
-    };
-}
-
 /// Schedule the next thread.
 ///
 /// It selects the next thread that should run from the runqueue.
@@ -201,22 +177,13 @@ fn get_next_pid(threads: &mut crate::Threads) -> Option<ThreadId> {
 #[no_mangle]
 unsafe fn sched() -> u128 {
     #[cfg(feature = "multicore")]
-    critical_section::with(|cs| {
-        let threads = unsafe { &mut *THREADS.as_ptr(cs) };
-        let Some(thread) = threads.current() else {
-            return;
-        };
-        if thread.state == crate::ThreadState::Running {
-            let prio = thread.prio;
-            let pid = thread.pid;
-            threads.runqueue.add(pid, prio);
-        }
-    });
+    THREADS.with_mut(|mut threads| threads.add_current_thread_to_rq());
+
     loop {
         if let Some(res) = critical_section::with(|cs| {
             let threads = unsafe { &mut *THREADS.as_ptr(cs) };
 
-            let next_pid = match get_next_pid(threads) {
+            let next_pid = match threads.get_next_pid() {
                 Some(pid) => pid,
                 None => {
                     #[cfg(feature = "multicore")]
diff --git a/src/riot-rs-threads/src/lib.rs b/src/riot-rs-threads/src/lib.rs
index 1f605b31c..637ca61e6 100644
--- a/src/riot-rs-threads/src/lib.rs
+++ b/src/riot-rs-threads/src/lib.rs
@@ -263,6 +263,46 @@ impl Threads {
         }
     }
 
+    #[cfg(feature = "multicore")]
+    fn add_current_thread_to_rq(&mut self) {
+        let Some(thread) = self.current() else {
+            return;
+        };
+        if thread.state == crate::ThreadState::Running {
+            let prio = thread.prio;
+            let pid = thread.pid;
+            self.runqueue.add(pid, prio);
+        }
+    }
+
+    #[allow(
+        dead_code,
+        reason = "used in context-specific scheduler implementation"
+    )]
+    fn get_next_pid(&mut self) -> Option<ThreadId> {
+        #[cfg(not(feature = "multicore"))]
+        {
+            return self.runqueue.get_next();
+        }
+        #[cfg(feature = "multicore")]
+        #[cfg(not(feature = "core-affinity"))]
+        {
+            return self.runqueue.pop_next();
+        }
+        #[cfg(feature = "core-affinity")]
+        {
+            let (mut next, prio) = self.runqueue.peek_next()?;
+            if !self.is_affine_to_curr_core(next) {
+                let iter = self.runqueue.iter_from(next, prio);
+                next = iter
+                    .filter(|pid| self.is_affine_to_curr_core(*pid))
+                    .next()?
+            }
+            self.runqueue.del(next);
+            return Some(next);
+        };
+    }
+
     #[cfg(feature = "multicore")]
     fn lowest_running_prio(&self, _pid: ThreadId) -> (CoreId, Option<RunqueueId>) {
         #[cfg(feature = "core-affinity")]