| Message ID | 20240730221742.2248527-2-matthew.brost@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Use user-defined workqueue lockdep map for drm sched | expand |
Hello, Matthew. On Tue, Jul 30, 2024 at 03:17:40PM -0700, Matthew Brost wrote: > +/** > + * wq_init_user_lockdep_map - init user lockdep map for workqueue > + * @wq: workqueue to init lockdep map for > + * @lockdep_map: lockdep map to use for workqueue > + * > + * Initialize workqueue with a user defined lockdep map. WQ_USER_OWNED_LOCKDEP > + * must be set for workqueue. > + */ > +void wq_init_user_lockdep_map(struct workqueue_struct *wq, > + struct lockdep_map *lockdep_map) > +{ > + if (WARN_ON_ONCE(!(wq->flags & WQ_USER_OWNED_LOCKDEP))) > + return; > + > + wq->lockdep_map = lockdep_map; > +} > +EXPORT_SYMBOL_GPL(wq_init_user_lockdep_map); Would it be possible to make it a one-piece interface - ie. add alloc_workqueue_lockdep_map() which takes an external lockdep map rather than splitting it over two calls? Thanks.
On Tue, Jul 30, 2024 at 12:34:08PM -1000, Tejun Heo wrote: > Hello, Matthew. > > On Tue, Jul 30, 2024 at 03:17:40PM -0700, Matthew Brost wrote: > > +/** > > + * wq_init_user_lockdep_map - init user lockdep map for workqueue > > + * @wq: workqueue to init lockdep map for > > + * @lockdep_map: lockdep map to use for workqueue > > + * > > + * Initialize workqueue with a user defined lockdep map. WQ_USER_OWNED_LOCKDEP > > + * must be set for workqueue. > > + */ > > +void wq_init_user_lockdep_map(struct workqueue_struct *wq, > > + struct lockdep_map *lockdep_map) > > +{ > > + if (WARN_ON_ONCE(!(wq->flags & WQ_USER_OWNED_LOCKDEP))) > > + return; > > + > > + wq->lockdep_map = lockdep_map; > > +} > > +EXPORT_SYMBOL_GPL(wq_init_user_lockdep_map); > > Would it be possible to make it a one-piece interface - ie. add > alloc_workqueue_lockdep_map() which takes an external lockdep map rather > than splitting it over two calls? > I didn't want to change the export alloc_workqueue() arguments so I went with this approach. Are you suggesting export a new function alloc_workqueue_lockdep_map() which will share an internal implementation with the existing alloc_workqueue() but passes in a lockdep map? That could work. Matt > Thanks. > > -- > tejun
On Tue, Jul 30, 2024 at 10:53:38PM +0000, Matthew Brost wrote: > I didn't want to change the export alloc_workqueue() arguments so I went > with this approach. Are you suggesting export a new function > alloc_workqueue_lockdep_map() which will share an internal > implementation with the existing alloc_workqueue() but passes in a > lockdep map? That could work. Yeah, add a new exported function which takes lockdep_map and make alloc_workqueue() to call that with the embedded map. No need to make the latter inline either. Thanks.
On Tue, Jul 30, 2024 at 12:56:17PM -1000, Tejun Heo wrote: > On Tue, Jul 30, 2024 at 10:53:38PM +0000, Matthew Brost wrote: > > I didn't want to change the export alloc_workqueue() arguments so I went > > with this approach. Are you suggesting export a new function > > alloc_workqueue_lockdep_map() which will share an internal > > implementation with the existing alloc_workqueue() but passes in a > > lockdep map? That could work. > > Yeah, add a new exported function which takes lockdep_map and make > alloc_workqueue() to call that with the embedded map. No need to make the > latter inline either. > Sure, let me do that. Matt > Thanks. > > -- > tejun
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index d9968bfc8eac..3e6db0889e2b 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -223,6 +223,8 @@ struct execute_work { }; #ifdef CONFIG_LOCKDEP +void wq_init_user_lockdep_map(struct workqueue_struct *wq, + struct lockdep_map *lockdep_map); /* * NB: because we have to copy the lockdep_map, setting _key * here is required, otherwise it could get initialised to the @@ -401,6 +403,7 @@ enum wq_flags { * http://thread.gmane.org/gmane.linux.kernel/1480396 */ WQ_POWER_EFFICIENT = 1 << 7, + WQ_USER_OWNED_LOCKDEP = 1 << 8, /* allow users to define lockdep map */ __WQ_DESTROYING = 1 << 15, /* internal: workqueue is destroying */ __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */ diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 3fbaecfc88c2..228b52b8d7c4 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -366,7 +366,8 @@ struct workqueue_struct { #ifdef CONFIG_LOCKDEP char *lock_name; struct lock_class_key key; - struct lockdep_map lockdep_map; + struct lockdep_map __lockdep_map; + struct lockdep_map *lockdep_map; #endif char name[WQ_NAME_LEN]; /* I: workqueue name */ @@ -3220,7 +3221,7 @@ __acquires(&pool->lock) lockdep_start_depth = lockdep_depth(current); /* see drain_dead_softirq_workfn() */ if (!bh_draining) - lock_map_acquire(&pwq->wq->lockdep_map); + lock_map_acquire(pwq->wq->lockdep_map); lock_map_acquire(&lockdep_map); /* * Strictly speaking we should mark the invariant state without holding @@ -3254,7 +3255,7 @@ __acquires(&pool->lock) pwq->stats[PWQ_STAT_COMPLETED]++; lock_map_release(&lockdep_map); if (!bh_draining) - lock_map_release(&pwq->wq->lockdep_map); + lock_map_release(pwq->wq->lockdep_map); if (unlikely((worker->task && in_atomic()) || lockdep_depth(current) != lockdep_start_depth || @@ -3892,8 +3893,8 @@ static void touch_wq_lockdep_map(struct workqueue_struct *wq) if (wq->flags & WQ_BH) local_bh_disable(); - lock_map_acquire(&wq->lockdep_map); - lock_map_release(&wq->lockdep_map); + lock_map_acquire(wq->lockdep_map); + lock_map_release(wq->lockdep_map); if (wq->flags & WQ_BH) local_bh_enable(); @@ -3927,7 +3928,8 @@ void __flush_workqueue(struct workqueue_struct *wq) struct wq_flusher this_flusher = { .list = LIST_HEAD_INIT(this_flusher.list), .flush_color = -1, - .done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, wq->lockdep_map), + .done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, + (*wq->lockdep_map)), }; int next_color; @@ -4778,26 +4780,54 @@ static int init_worker_pool(struct worker_pool *pool) } #ifdef CONFIG_LOCKDEP +/** + * wq_init_user_lockdep_map - init user lockdep map for workqueue + * @wq: workqueue to init lockdep map for + * @lockdep_map: lockdep map to use for workqueue + * + * Initialize workqueue with a user defined lockdep map. WQ_USER_OWNED_LOCKDEP + * must be set for workqueue. + */ +void wq_init_user_lockdep_map(struct workqueue_struct *wq, + struct lockdep_map *lockdep_map) +{ + if (WARN_ON_ONCE(!(wq->flags & WQ_USER_OWNED_LOCKDEP))) + return; + + wq->lockdep_map = lockdep_map; +} +EXPORT_SYMBOL_GPL(wq_init_user_lockdep_map); + static void wq_init_lockdep(struct workqueue_struct *wq) { char *lock_name; + if (wq->flags & WQ_USER_OWNED_LOCKDEP) + return; + lockdep_register_key(&wq->key); lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name); if (!lock_name) lock_name = wq->name; wq->lock_name = lock_name; - lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0); + wq->lockdep_map = &wq->__lockdep_map; + lockdep_init_map(wq->lockdep_map, lock_name, &wq->key, 0); } static void wq_unregister_lockdep(struct workqueue_struct *wq) { + if (wq->flags & WQ_USER_OWNED_LOCKDEP) + return; + lockdep_unregister_key(&wq->key); } static void wq_free_lockdep(struct workqueue_struct *wq) { + if (wq->flags & WQ_USER_OWNED_LOCKDEP) + return; + if (wq->lock_name != wq->name) kfree(wq->lock_name); }
Add an interface for a user-defined workqueue lockdep map, which is helpful when multiple workqueues are created for the same purpose. This also helps avoid leaking lockdep maps on each workqueue creation. Implement a new workqueue flag, WQ_USER_OWNED_LOCKDEP, to indicate that the user will set up the workqueue lockdep map using the new function wq_init_user_lockdep_map. Cc: Tejun Heo <tj@kernel.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Matthew Brost <matthew.brost@intel.com> --- include/linux/workqueue.h | 3 +++ kernel/workqueue.c | 44 ++++++++++++++++++++++++++++++++------- 2 files changed, 40 insertions(+), 7 deletions(-)