[PATCH v14 08/28] dept: Distinguish each work from another

From: Byungchul Park
Date: Wed May 08 2024 - 06:10:48 EST


Workqueue already provides concurrency control. By that, any wait in a
work doesn't prevents events in other works with the control enabled.
Thus, each work would better be considered a different context.

So let Dept assign a different context id to each work.

Signed-off-by: Byungchul Park <byungchul@xxxxxx>
---
include/linux/dept.h | 2 ++
kernel/dependency/dept.c | 10 ++++++++++
kernel/workqueue.c | 3 +++
3 files changed, 15 insertions(+)

diff --git a/include/linux/dept.h b/include/linux/dept.h
index 4e359f76ac3c..319a5b43df89 100644
--- a/include/linux/dept.h
+++ b/include/linux/dept.h
@@ -509,6 +509,7 @@ extern void dept_ecxt_exit(struct dept_map *m, unsigned long e_f, unsigned long
extern void dept_sched_enter(void);
extern void dept_sched_exit(void);
extern void dept_kernel_enter(void);
+extern void dept_work_enter(void);

static inline void dept_ecxt_enter_nokeep(struct dept_map *m)
{
@@ -559,6 +560,7 @@ struct dept_task { };
#define dept_sched_enter() do { } while (0)
#define dept_sched_exit() do { } while (0)
#define dept_kernel_enter() do { } while (0)
+#define dept_work_enter() do { } while (0)
#define dept_ecxt_enter_nokeep(m) do { } while (0)
#define dept_key_init(k) do { (void)(k); } while (0)
#define dept_key_destroy(k) do { (void)(k); } while (0)
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index 9aba9eb22760..a8e693fd590f 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -1933,6 +1933,16 @@ void noinstr dept_hardirqs_off(void)
dept_task()->hardirqs_enabled = false;
}

+/*
+ * Assign a different context id to each work.
+ */
+void dept_work_enter(void)
+{
+ struct dept_task *dt = dept_task();
+
+ dt->cxt_id[DEPT_CXT_PROCESS] += 1UL << DEPT_CXTS_NR;
+}
+
void noinstr dept_kernel_enter(void)
{
struct dept_task *dt = dept_task();
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index d2dbe099286b..e7b3818a26eb 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -55,6 +55,7 @@
#include <linux/kvm_para.h>
#include <linux/delay.h>
#include <linux/irq_work.h>
+#include <linux/dept.h>

#include "workqueue_internal.h"

@@ -3184,6 +3185,8 @@ __acquires(&pool->lock)

lockdep_copy_map(&lockdep_map, &work->lockdep_map);
#endif
+ dept_work_enter();
+
/* ensure we're on the correct CPU */
WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
raw_smp_processor_id() != pool->cpu);
--
2.17.1