[Minios-devel] [UNIKRAFT PATCH v3 06/12] lib/uksched: Revisit thread exiting logic

[Costin Lupu <costin.lupu@xxxxxxxxx>]

We use a list for terminated threads on all schedulers because it
keeps references to those threads until wait is called for them.

Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
Reviewed-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
---
 lib/uksched/include/uk/sched.h |  1 +
 lib/uksched/sched.c            |  7 ++++---
 lib/ukschedcoop/schedcoop.c    | 11 +++--------
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/lib/uksched/include/uk/sched.h b/lib/uksched/include/uk/sched.h
index 9554c6e1..e5630ed6 100644
--- a/lib/uksched/include/uk/sched.h
+++ b/lib/uksched/include/uk/sched.h
@@ -87,6 +87,7 @@ struct uk_sched {
 
        /* internal */
        struct uk_thread idle;
+       struct uk_thread_list exited_threads;
        struct ukplat_ctx_callbacks plat_ctx_cbs;
        struct uk_alloc *allocator;
        struct uk_sched *next;
diff --git a/lib/uksched/sched.c b/lib/uksched/sched.c
index d7ca7f35..a0d706f5 100644
--- a/lib/uksched/sched.c
+++ b/lib/uksched/sched.c
@@ -122,6 +122,7 @@ struct uk_sched *uk_sched_create(struct uk_alloc *a, size_t 
prv_size)
        }
 
        sched->allocator = a;
+       UK_TAILQ_INIT(&sched->exited_threads);
        sched->prv = (void *) sched + sizeof(struct uk_sched);
 
        return sched;
@@ -213,6 +214,9 @@ void uk_sched_thread_destroy(struct uk_sched *sched, struct 
uk_thread *thread)
 {
        UK_ASSERT(sched != NULL);
        UK_ASSERT(thread != NULL);
+       UK_ASSERT(is_exited(thread));
+
+       UK_TAILQ_REMOVE(&sched->exited_threads, thread, thread_list);
        uk_thread_fini(thread, sched->allocator);
        uk_pfree(sched->allocator, thread->stack, STACK_SIZE_PAGE_ORDER);
        uk_free(sched->allocator, thread);
@@ -232,9 +236,6 @@ void uk_sched_thread_exit(void)
        struct uk_thread *thread;
 
        thread = uk_thread_current();
-
-       uk_pr_info("Thread \"%s\" exited.\n", thread->name);
-
        UK_ASSERT(thread->sched);
        uk_sched_thread_remove(thread->sched, thread);
        UK_CRASH("Error stopping thread.");
diff --git a/lib/ukschedcoop/schedcoop.c b/lib/ukschedcoop/schedcoop.c
index 5091c913..2a646760 100644
--- a/lib/ukschedcoop/schedcoop.c
+++ b/lib/ukschedcoop/schedcoop.c
@@ -36,7 +36,6 @@
 
 struct schedcoop_private {
        struct uk_thread_list thread_list;
-       struct uk_thread_list exited_threads;
        int threads_started;
 };
 
@@ -123,16 +122,13 @@ static void schedcoop_schedule(struct uk_sched *s)
        if (prev != next)
                uk_sched_thread_switch(s, prev, next);
 
-       UK_TAILQ_FOREACH_SAFE(thread, &prv->exited_threads, thread_list, tmp) {
+       UK_TAILQ_FOREACH_SAFE(thread, &s->exited_threads, thread_list, tmp) {
                if (!thread->detached)
                        /* someone will eventually wait for it */
                        continue;
 
-               if (thread != prev) {
-                       UK_TAILQ_REMOVE(&prv->exited_threads,
-                                       thread, thread_list);
+               if (thread != prev)
                        uk_thread_destroy(thread);
-               }
        }
 }
 
@@ -163,7 +159,7 @@ static void schedcoop_thread_remove(struct uk_sched *s, 
struct uk_thread *t)
        uk_thread_exit(t);
 
        /* Put onto exited list */
-       UK_TAILQ_INSERT_HEAD(&prv->exited_threads, t, thread_list);
+       UK_TAILQ_INSERT_HEAD(&s->exited_threads, t, thread_list);
 
        ukplat_lcpu_restore_irqf(flags);
 
@@ -208,7 +204,6 @@ struct uk_sched *uk_schedcoop_init(struct uk_alloc *a)
        ukplat_ctx_callbacks_init(&sched->plat_ctx_cbs, ukplat_ctx_sw);
 
        prv = sched->prv;
-       UK_TAILQ_INIT(&prv->exited_threads);
        UK_TAILQ_INIT(&prv->thread_list);
        prv->threads_started = 0;
 
-- 
2.11.0


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