[PATCH v10 13/25] dept: Distinguish each work from another

Byungchul Park
2023-06-26T12:50:17Z

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@sk.com>
---
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 f62c7b6f42c6..d9ca9dd50219 100644
--- a/include/linux/dept.h
+++ b/include/linux/dept.h
@@ -515,6 +515,7 @@ 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)
{
@@ -567,6 +568,7 @@ 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 4165cacf4ebb..6cf17f206b78 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -1977,6 +1977,16 @@ void dept_hardirqs_off_ip(unsigned long ip)
}
EXPORT_SYMBOL_GPL(dept_hardirqs_off_ip);

+/*
+ * 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 dept_kernel_enter(void)
{
struct dept_task *dt = dept_task();
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 07895deca271..69c4f464d017 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -51,6 +51,7 @@
#include <linux/sched/isolation.h>
#include <linux/nmi.h>
#include <linux/kvm_para.h>
+#include <linux/dept.h>

#include "workqueue_internal.h"

@@ -2199,6 +2200,8 @@ __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