[Intel-gfx] [PATCH 04/27] drm/i915/guc: Take GT PM ref when deregistering context
Matthew Brost
matthew.brost at intel.com
Mon Sep 13 17:12:09 UTC 2021
On Mon, Sep 13, 2021 at 10:55:59AM +0100, Tvrtko Ursulin wrote:
>
> On 20/08/2021 23:44, Matthew Brost wrote:
> > Taking a PM reference to prevent intel_gt_wait_for_idle from short
> > circuiting while a deregister context H2G is in flight.
> >
> > FIXME: Move locking / structure changes into different patch
> >
> > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> > ---
> > drivers/gpu/drm/i915/gt/intel_context.c | 2 +
> > drivers/gpu/drm/i915/gt/intel_context_types.h | 13 +-
> > drivers/gpu/drm/i915/gt/intel_engine_pm.h | 5 +
> > drivers/gpu/drm/i915/gt/intel_gt_pm.h | 13 ++
> > .../gpu/drm/i915/gt/uc/abi/guc_actions_abi.h | 1 +
> > drivers/gpu/drm/i915/gt/uc/intel_guc.h | 46 ++--
> > .../gpu/drm/i915/gt/uc/intel_guc_debugfs.c | 13 +-
> > .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 212 +++++++++++-------
> > 8 files changed, 199 insertions(+), 106 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
> > index adfe49b53b1b..c8595da64ad8 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_context.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_context.c
> > @@ -399,6 +399,8 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
> > ce->guc_id.id = GUC_INVALID_LRC_ID;
> > INIT_LIST_HEAD(&ce->guc_id.link);
> > + INIT_LIST_HEAD(&ce->destroyed_link);
> > +
> > /*
> > * Initialize fence to be complete as this is expected to be complete
> > * unless there is a pending schedule disable outstanding.
> > diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> > index 80bbdc7810f6..fd338a30617e 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> > @@ -190,22 +190,29 @@ struct intel_context {
> > /**
> > * @id: unique handle which is used to communicate information
> > * with the GuC about this context, protected by
> > - * guc->contexts_lock
> > + * guc->submission_state.lock
> > */
> > u16 id;
> > /**
> > * @ref: the number of references to the guc_id, when
> > * transitioning in and out of zero protected by
> > - * guc->contexts_lock
> > + * guc->submission_state.lock
> > */
> > atomic_t ref;
> > /**
> > * @link: in guc->guc_id_list when the guc_id has no refs but is
> > - * still valid, protected by guc->contexts_lock
> > + * still valid, protected by guc->submission_state.lock
> > */
> > struct list_head link;
> > } guc_id;
> > + /**
> > + * @destroyed_link: link in guc->submission_state.destroyed_contexts, in
> > + * list when context is pending to be destroyed (deregistered with the
> > + * GuC), protected by guc->submission_state.lock
> > + */
> > + struct list_head destroyed_link;
> > +
> > #ifdef CONFIG_DRM_I915_SELFTEST
> > /**
> > * @drop_schedule_enable: Force drop of schedule enable G2H for selftest
> > diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.h b/drivers/gpu/drm/i915/gt/intel_engine_pm.h
> > index 70ea46d6cfb0..17a5028ea177 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_engine_pm.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.h
> > @@ -16,6 +16,11 @@ intel_engine_pm_is_awake(const struct intel_engine_cs *engine)
> > return intel_wakeref_is_active(&engine->wakeref);
> > }
> > +static inline void __intel_engine_pm_get(struct intel_engine_cs *engine)
> > +{
> > + __intel_wakeref_get(&engine->wakeref);
> > +}
> > +
> > static inline void intel_engine_pm_get(struct intel_engine_cs *engine)
> > {
> > intel_wakeref_get(&engine->wakeref);
> > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> > index d0588d8aaa44..a17bf0d4592b 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> > @@ -41,6 +41,19 @@ static inline void intel_gt_pm_put_async(struct intel_gt *gt)
> > intel_wakeref_put_async(>->wakeref);
> > }
> > +#define with_intel_gt_pm(gt, tmp) \
> > + for (tmp = 1, intel_gt_pm_get(gt); tmp; \
> > + intel_gt_pm_put(gt), tmp = 0)
> > +#define with_intel_gt_pm_async(gt, tmp) \
> > + for (tmp = 1, intel_gt_pm_get(gt); tmp; \
> > + intel_gt_pm_put_async(gt), tmp = 0)
> > +#define with_intel_gt_pm_if_awake(gt, tmp) \
> > + for (tmp = intel_gt_pm_get_if_awake(gt); tmp; \
> > + intel_gt_pm_put(gt), tmp = 0)
> > +#define with_intel_gt_pm_if_awake_async(gt, tmp) \
> > + for (tmp = intel_gt_pm_get_if_awake(gt); tmp; \
> > + intel_gt_pm_put_async(gt), tmp = 0)
> > +
> > static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt)
> > {
> > return intel_wakeref_wait_for_idle(>->wakeref);
> > diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
> > index 8ff582222aff..ba10bd374cee 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
> > +++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
> > @@ -142,6 +142,7 @@ enum intel_guc_action {
> > INTEL_GUC_ACTION_REGISTER_COMMAND_TRANSPORT_BUFFER = 0x4505,
> > INTEL_GUC_ACTION_DEREGISTER_COMMAND_TRANSPORT_BUFFER = 0x4506,
> > INTEL_GUC_ACTION_DEREGISTER_CONTEXT_DONE = 0x4600,
> > + INTEL_GUC_ACTION_REGISTER_CONTEXT_MULTI_LRC = 0x4601,
> > INTEL_GUC_ACTION_RESET_CLIENT = 0x5507,
> > INTEL_GUC_ACTION_LIMIT
> > };
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > index 6fd2719d1b75..7358883f1540 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > @@ -53,21 +53,37 @@ struct intel_guc {
> > void (*disable)(struct intel_guc *guc);
> > } interrupts;
> > - /**
> > - * @contexts_lock: protects guc_ids, guc_id_list, ce->guc_id.id, and
> > - * ce->guc_id.ref when transitioning in and out of zero
> > - */
> > - spinlock_t contexts_lock;
> > - /** @guc_ids: used to allocate new guc_ids */
> > - struct ida guc_ids;
> > - /** @num_guc_ids: number of guc_ids that can be used */
> > - u32 num_guc_ids;
> > - /** @max_guc_ids: max number of guc_ids that can be used */
> > - u32 max_guc_ids;
> > - /**
> > - * @guc_id_list: list of intel_context with valid guc_ids but no refs
> > - */
> > - struct list_head guc_id_list;
> > + struct {
> > + /**
> > + * @lock: protects everything in submission_state, ce->guc_id,
> > + * and ce->destroyed_link
> > + */
> > + spinlock_t lock;
> > + /**
> > + * @guc_ids: used to allocate new guc_ids
> > + */
> > + struct ida guc_ids;
> > + /** @num_guc_ids: number of guc_ids that can be used */
> > + u32 num_guc_ids;
> > + /** @max_guc_ids: max number of guc_ids that can be used */
> > + u32 max_guc_ids;
> > + /**
> > + * @guc_id_list: list of intel_context with valid guc_ids but no
> > + * refs
> > + */
> > + struct list_head guc_id_list;
> > + /**
> > + * @destroyed_contexts: list of contexts waiting to be destroyed
> > + * (deregistered with the GuC)
> > + */
> > + struct list_head destroyed_contexts;
> > + /**
> > + * @destroyed_worker: worker to deregister contexts, need as we
> > + * need to take a GT PM reference and can't from destroy
> > + * function as it might be in an atomic context (no sleeping)
> > + */
> > + struct work_struct destroyed_worker;
> > + } submission_state;
> > bool submission_supported;
> > bool submission_selected;
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_debugfs.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_debugfs.c
> > index b88d343ee432..27655460ee84 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_debugfs.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_debugfs.c
> > @@ -78,7 +78,7 @@ static int guc_num_id_get(void *data, u64 *val)
> > if (!intel_guc_submission_is_used(guc))
> > return -ENODEV;
> > - *val = guc->num_guc_ids;
> > + *val = guc->submission_state.num_guc_ids;
> > return 0;
> > }
> > @@ -86,16 +86,21 @@ static int guc_num_id_get(void *data, u64 *val)
> > static int guc_num_id_set(void *data, u64 val)
> > {
> > struct intel_guc *guc = data;
> > + unsigned long flags;
> > if (!intel_guc_submission_is_used(guc))
> > return -ENODEV;
> > - if (val > guc->max_guc_ids)
> > - val = guc->max_guc_ids;
> > + spin_lock_irqsave(&guc->submission_state.lock, flags);
> > +
> > + if (val > guc->submission_state.max_guc_ids)
> > + val = guc->submission_state.max_guc_ids;
> > else if (val < 256)
> > val = 256;
> > - guc->num_guc_ids = val;
> > + guc->submission_state.num_guc_ids = val;
> > +
> > + spin_unlock_irqrestore(&guc->submission_state.lock, flags);
> > return 0;
> > }
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > index 68742b612692..f835e06e5f9f 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > @@ -86,9 +86,9 @@
> > * submitting at a time. Currently only 1 sched_engine used for all of GuC
> > * submission but that could change in the future.
> > *
> > - * guc->contexts_lock
> > - * Protects guc_id allocation. Global lock i.e. Only 1 context that uses GuC
> > - * submission can hold this at a time.
> > + * guc->submission_state.lock
> > + * Global lock for GuC submission state. Protects guc_ids and destroyed contexts
> > + * list.
> > *
> > * ce->guc_state.lock
> > * Protects everything under ce->guc_state. Ensures that a context is in the
> > @@ -100,7 +100,7 @@
> > *
> > * Lock ordering rules:
> > * sched_engine->lock -> ce->guc_state.lock
> > - * guc->contexts_lock -> ce->guc_state.lock
> > + * guc->submission_state.lock -> ce->guc_state.lock
> > *
> > * Reset races:
> > * When a GPU full reset is triggered it is assumed that some G2H responses to
> > @@ -344,7 +344,7 @@ static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, u32 index)
> > {
> > struct guc_lrc_desc *base = guc->lrc_desc_pool_vaddr;
> > - GEM_BUG_ON(index >= guc->max_guc_ids);
> > + GEM_BUG_ON(index >= guc->submission_state.max_guc_ids);
> > return &base[index];
> > }
> > @@ -353,7 +353,7 @@ static struct intel_context *__get_context(struct intel_guc *guc, u32 id)
> > {
> > struct intel_context *ce = xa_load(&guc->context_lookup, id);
> > - GEM_BUG_ON(id >= guc->max_guc_ids);
> > + GEM_BUG_ON(id >= guc->submission_state.max_guc_ids);
> > return ce;
> > }
> > @@ -363,7 +363,8 @@ static int guc_lrc_desc_pool_create(struct intel_guc *guc)
> > u32 size;
> > int ret;
> > - size = PAGE_ALIGN(sizeof(struct guc_lrc_desc) * guc->max_guc_ids);
> > + size = PAGE_ALIGN(sizeof(struct guc_lrc_desc) *
> > + guc->submission_state.max_guc_ids);
> > ret = intel_guc_allocate_and_map_vma(guc, size, &guc->lrc_desc_pool,
> > (void **)&guc->lrc_desc_pool_vaddr);
> > if (ret)
> > @@ -711,6 +712,7 @@ static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc)
> > if (deregister)
> > guc_signal_context_fence(ce);
> > if (destroyed) {
> > + intel_gt_pm_put_async(guc_to_gt(guc));
> > release_guc_id(guc, ce);
> > __guc_context_destroy(ce);
> > }
> > @@ -789,6 +791,8 @@ static void guc_flush_submissions(struct intel_guc *guc)
> > spin_unlock_irqrestore(&sched_engine->lock, flags);
> > }
> > +static void guc_flush_destroyed_contexts(struct intel_guc *guc);
> > +
> > void intel_guc_submission_reset_prepare(struct intel_guc *guc)
> > {
> > if (unlikely(!guc_submission_initialized(guc))) {
> > @@ -805,6 +809,7 @@ void intel_guc_submission_reset_prepare(struct intel_guc *guc)
> > spin_unlock_irq(&guc_to_gt(guc)->irq_lock);
> > flush_work(&guc->ct.requests.worker);
> > + guc_flush_destroyed_contexts(guc);
> > scrub_guc_desc_for_outstanding_g2h(guc);
> > }
> > @@ -1102,6 +1107,8 @@ void intel_guc_submission_reset_finish(struct intel_guc *guc)
> > intel_gt_unpark_heartbeats(guc_to_gt(guc));
> > }
> > +static void destroyed_worker_func(struct work_struct *w);
> > +
> > /*
> > * Set up the memory resources to be shared with the GuC (via the GGTT)
> > * at firmware loading time.
> > @@ -1124,9 +1131,11 @@ int intel_guc_submission_init(struct intel_guc *guc)
> > xa_init_flags(&guc->context_lookup, XA_FLAGS_LOCK_IRQ);
> > - spin_lock_init(&guc->contexts_lock);
> > - INIT_LIST_HEAD(&guc->guc_id_list);
> > - ida_init(&guc->guc_ids);
> > + spin_lock_init(&guc->submission_state.lock);
> > + INIT_LIST_HEAD(&guc->submission_state.guc_id_list);
> > + ida_init(&guc->submission_state.guc_ids);
> > + INIT_LIST_HEAD(&guc->submission_state.destroyed_contexts);
> > + INIT_WORK(&guc->submission_state.destroyed_worker, destroyed_worker_func);
> > return 0;
> > }
> > @@ -1137,6 +1146,7 @@ void intel_guc_submission_fini(struct intel_guc *guc)
> > return;
> > guc_lrc_desc_pool_destroy(guc);
> > + guc_flush_destroyed_contexts(guc);
> > i915_sched_engine_put(guc->sched_engine);
> > }
> > @@ -1191,15 +1201,16 @@ static void guc_submit_request(struct i915_request *rq)
> > static int new_guc_id(struct intel_guc *guc)
> > {
> > - return ida_simple_get(&guc->guc_ids, 0,
> > - guc->num_guc_ids, GFP_KERNEL |
> > + return ida_simple_get(&guc->submission_state.guc_ids, 0,
> > + guc->submission_state.num_guc_ids, GFP_KERNEL |
> > __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
> > }
> > static void __release_guc_id(struct intel_guc *guc, struct intel_context *ce)
> > {
> > if (!context_guc_id_invalid(ce)) {
> > - ida_simple_remove(&guc->guc_ids, ce->guc_id.id);
> > + ida_simple_remove(&guc->submission_state.guc_ids,
> > + ce->guc_id.id);
> > reset_lrc_desc(guc, ce->guc_id.id);
> > set_context_guc_id_invalid(ce);
> > }
> > @@ -1211,9 +1222,9 @@ static void release_guc_id(struct intel_guc *guc, struct intel_context *ce)
> > {
> > unsigned long flags;
> > - spin_lock_irqsave(&guc->contexts_lock, flags);
> > + spin_lock_irqsave(&guc->submission_state.lock, flags);
> > __release_guc_id(guc, ce);
> > - spin_unlock_irqrestore(&guc->contexts_lock, flags);
> > + spin_unlock_irqrestore(&guc->submission_state.lock, flags);
> > }
> > static int steal_guc_id(struct intel_guc *guc)
> > @@ -1221,10 +1232,10 @@ static int steal_guc_id(struct intel_guc *guc)
> > struct intel_context *ce;
> > int guc_id;
> > - lockdep_assert_held(&guc->contexts_lock);
> > + lockdep_assert_held(&guc->submission_state.lock);
> > - if (!list_empty(&guc->guc_id_list)) {
> > - ce = list_first_entry(&guc->guc_id_list,
> > + if (!list_empty(&guc->submission_state.guc_id_list)) {
> > + ce = list_first_entry(&guc->submission_state.guc_id_list,
> > struct intel_context,
> > guc_id.link);
> > @@ -1249,7 +1260,7 @@ static int assign_guc_id(struct intel_guc *guc, u16 *out)
> > {
> > int ret;
> > - lockdep_assert_held(&guc->contexts_lock);
> > + lockdep_assert_held(&guc->submission_state.lock);
> > ret = new_guc_id(guc);
> > if (unlikely(ret < 0)) {
> > @@ -1271,7 +1282,7 @@ static int pin_guc_id(struct intel_guc *guc, struct intel_context *ce)
> > GEM_BUG_ON(atomic_read(&ce->guc_id.ref));
> > try_again:
> > - spin_lock_irqsave(&guc->contexts_lock, flags);
> > + spin_lock_irqsave(&guc->submission_state.lock, flags);
> > might_lock(&ce->guc_state.lock);
> > @@ -1286,7 +1297,7 @@ static int pin_guc_id(struct intel_guc *guc, struct intel_context *ce)
> > atomic_inc(&ce->guc_id.ref);
> > out_unlock:
> > - spin_unlock_irqrestore(&guc->contexts_lock, flags);
> > + spin_unlock_irqrestore(&guc->submission_state.lock, flags);
> > /*
> > * -EAGAIN indicates no guc_id are available, let's retire any
> > @@ -1322,11 +1333,12 @@ static void unpin_guc_id(struct intel_guc *guc, struct intel_context *ce)
> > if (unlikely(context_guc_id_invalid(ce)))
> > return;
> > - spin_lock_irqsave(&guc->contexts_lock, flags);
> > + spin_lock_irqsave(&guc->submission_state.lock, flags);
> > if (!context_guc_id_invalid(ce) && list_empty(&ce->guc_id.link) &&
> > !atomic_read(&ce->guc_id.ref))
> > - list_add_tail(&ce->guc_id.link, &guc->guc_id_list);
> > - spin_unlock_irqrestore(&guc->contexts_lock, flags);
> > + list_add_tail(&ce->guc_id.link,
> > + &guc->submission_state.guc_id_list);
> > + spin_unlock_irqrestore(&guc->submission_state.lock, flags);
> > }
> > static int __guc_action_register_context(struct intel_guc *guc,
> > @@ -1841,11 +1853,30 @@ static void guc_context_sched_disable(struct intel_context *ce)
> > static void guc_lrc_desc_unpin(struct intel_context *ce)
> > {
> > struct intel_guc *guc = ce_to_guc(ce);
> > + struct intel_gt *gt = guc_to_gt(guc);
> > + unsigned long flags;
> > + bool disabled;
> > + GEM_BUG_ON(!intel_gt_pm_is_awake(gt));
> > GEM_BUG_ON(!lrc_desc_registered(guc, ce->guc_id.id));
> > GEM_BUG_ON(ce != __get_context(guc, ce->guc_id.id));
> > GEM_BUG_ON(context_enabled(ce));
> > + /* Seal race with Reset */
> > + spin_lock_irqsave(&ce->guc_state.lock, flags);
> > + disabled = submission_disabled(guc);
> > + if (likely(!disabled)) {
> > + __intel_gt_pm_get(gt);
> > + set_context_destroyed(ce);
> > + clr_context_registered(ce);
> > + }
> > + spin_unlock_irqrestore(&ce->guc_state.lock, flags);
> > + if (unlikely(disabled)) {
> > + release_guc_id(guc, ce);
> > + __guc_context_destroy(ce);
> > + return;
> > + }
> > +
> > deregister_context(ce, ce->guc_id.id, true);
> > }
> > @@ -1873,78 +1904,88 @@ static void __guc_context_destroy(struct intel_context *ce)
> > }
> > }
> > +static void guc_flush_destroyed_contexts(struct intel_guc *guc)
> > +{
> > + struct intel_context *ce, *cn;
> > + unsigned long flags;
> > +
> > + GEM_BUG_ON(!submission_disabled(guc) &&
> > + guc_submission_initialized(guc));
> > +
> > + spin_lock_irqsave(&guc->submission_state.lock, flags);
> > + list_for_each_entry_safe(ce, cn,
> > + &guc->submission_state.destroyed_contexts,
> > + destroyed_link) {
> > + list_del_init(&ce->destroyed_link);
> > + __release_guc_id(guc, ce);
> > + __guc_context_destroy(ce);
> > + }
> > + spin_unlock_irqrestore(&guc->submission_state.lock, flags);
> > +}
> > +
> > +static void deregister_destroyed_contexts(struct intel_guc *guc)
> > +{
> > + struct intel_context *ce, *cn;
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(&guc->submission_state.lock, flags);
> > + list_for_each_entry_safe(ce, cn,
> > + &guc->submission_state.destroyed_contexts,
> > + destroyed_link) {
> > + list_del_init(&ce->destroyed_link);
> > + spin_unlock_irqrestore(&guc->submission_state.lock, flags);
>
> Lock drop and re-acquire is not safe - list_for_each_entry_safe only deal
> with the list_del_init above. It does not help if someone else modifies the
> list in the window while the lock is not held, in which case things will go
> BOOM!
>
Good catch, but is this true? We always add via list_add_tail which if
I'm reading the list_for_each_entry_safe macro correctly I think is safe
to do as 'n = list_next_entry(n, member)' will just evaluate to the new
tail on each iteration, right?
Reference to macro below:
#define list_for_each_entry_safe(pos, n, head, member) \
for (pos = list_first_entry(head, typeof(*pos), member), \
n = list_next_entry(pos, member); \
&pos->member != (head); \
pos = n, n = list_next_entry(n, member))
Regardless probably safer to just not drop the lock.
> Not sure in what differnt ways you use this list, but perhaps you could
> employ a lockless single linked list for this. In which case you could
> atomically unlink all elements. Or just change this to not do lock dropping,
> if you can safely use the same list_head to put on a local list or
> something.
>
I think both options work - not sure why I drop the lock here. I'll play
around with this and fix in the next rev.
Matt
> Regards,
>
> Tvrtko
>
> > + guc_lrc_desc_unpin(ce);
> > + spin_lock_irqsave(&guc->submission_state.lock, flags);
> > + }
> > + spin_unlock_irqrestore(&guc->submission_state.lock, flags);
> > +}
> > +
> > +static void destroyed_worker_func(struct work_struct *w)
> > +{
> > + struct intel_guc *guc = container_of(w, struct intel_guc,
> > + submission_state.destroyed_worker);
> > + struct intel_gt *gt = guc_to_gt(guc);
> > + int tmp;
> > +
> > + with_intel_gt_pm(gt, tmp)
> > + deregister_destroyed_contexts(guc);
> > +}
> > +
> > static void guc_context_destroy(struct kref *kref)
> > {
> > struct intel_context *ce = container_of(kref, typeof(*ce), ref);
> > - struct intel_runtime_pm *runtime_pm = ce->engine->uncore->rpm;
> > struct intel_guc *guc = ce_to_guc(ce);
> > - intel_wakeref_t wakeref;
> > unsigned long flags;
> > - bool disabled;
> > + bool destroy;
> > /*
> > * If the guc_id is invalid this context has been stolen and we can free
> > * it immediately. Also can be freed immediately if the context is not
> > * registered with the GuC or the GuC is in the middle of a reset.
> > */
> > - if (context_guc_id_invalid(ce)) {
> > - __guc_context_destroy(ce);
> > - return;
> > - } else if (submission_disabled(guc) ||
> > - !lrc_desc_registered(guc, ce->guc_id.id)) {
> > - release_guc_id(guc, ce);
> > - __guc_context_destroy(ce);
> > - return;
> > - }
> > -
> > - /*
> > - * We have to acquire the context spinlock and check guc_id again, if it
> > - * is valid it hasn't been stolen and needs to be deregistered. We
> > - * delete this context from the list of unpinned guc_id available to
> > - * steal to seal a race with guc_lrc_desc_pin(). When the G2H CTB
> > - * returns indicating this context has been deregistered the guc_id is
> > - * returned to the pool of available guc_id.
> > - */
> > - spin_lock_irqsave(&guc->contexts_lock, flags);
> > - if (context_guc_id_invalid(ce)) {
> > - spin_unlock_irqrestore(&guc->contexts_lock, flags);
> > - __guc_context_destroy(ce);
> > - return;
> > - }
> > -
> > - if (!list_empty(&ce->guc_id.link))
> > - list_del_init(&ce->guc_id.link);
> > - spin_unlock_irqrestore(&guc->contexts_lock, flags);
> > -
> > - /* Seal race with Reset */
> > - spin_lock_irqsave(&ce->guc_state.lock, flags);
> > - disabled = submission_disabled(guc);
> > - if (likely(!disabled)) {
> > - set_context_destroyed(ce);
> > - clr_context_registered(ce);
> > + spin_lock_irqsave(&guc->submission_state.lock, flags);
> > + destroy = submission_disabled(guc) || context_guc_id_invalid(ce) ||
> > + !lrc_desc_registered(guc, ce->guc_id.id);
> > + if (likely(!destroy)) {
> > + if (!list_empty(&ce->guc_id.link))
> > + list_del_init(&ce->guc_id.link);
> > + list_add_tail(&ce->destroyed_link,
> > + &guc->submission_state.destroyed_contexts);
> > + } else {
> > + __release_guc_id(guc, ce);
> > }
> > - spin_unlock_irqrestore(&ce->guc_state.lock, flags);
> > - if (unlikely(disabled)) {
> > - release_guc_id(guc, ce);
> > + spin_unlock_irqrestore(&guc->submission_state.lock, flags);
> > + if (unlikely(destroy)) {
> > __guc_context_destroy(ce);
> > return;
> > }
> > /*
> > - * We defer GuC context deregistration until the context is destroyed
> > - * in order to save on CTBs. With this optimization ideally we only need
> > - * 1 CTB to register the context during the first pin and 1 CTB to
> > - * deregister the context when the context is destroyed. Without this
> > - * optimization, a CTB would be needed every pin & unpin.
> > - *
> > - * XXX: Need to acqiure the runtime wakeref as this can be triggered
> > - * from context_free_worker when runtime wakeref is not held.
> > - * guc_lrc_desc_unpin requires the runtime as a GuC register is written
> > - * in H2G CTB to deregister the context. A future patch may defer this
> > - * H2G CTB if the runtime wakeref is zero.
> > + * We use a worker to issue the H2G to deregister the context as we can
> > + * take the GT PM for the first time which isn't allowed from an atomic
> > + * context.
> > */
> > - with_intel_runtime_pm(runtime_pm, wakeref)
> > - guc_lrc_desc_unpin(ce);
> > + queue_work(system_unbound_wq, &guc->submission_state.destroyed_worker);
> > }
> > static int guc_context_alloc(struct intel_context *ce)
> > @@ -2703,8 +2744,8 @@ static bool __guc_submission_selected(struct intel_guc *guc)
> > void intel_guc_submission_init_early(struct intel_guc *guc)
> > {
> > - guc->max_guc_ids = GUC_MAX_LRC_DESCRIPTORS;
> > - guc->num_guc_ids = GUC_MAX_LRC_DESCRIPTORS;
> > + guc->submission_state.max_guc_ids = GUC_MAX_LRC_DESCRIPTORS;
> > + guc->submission_state.num_guc_ids = GUC_MAX_LRC_DESCRIPTORS;
> > guc->submission_supported = __guc_submission_supported(guc);
> > guc->submission_selected = __guc_submission_selected(guc);
> > }
> > @@ -2714,10 +2755,10 @@ g2h_context_lookup(struct intel_guc *guc, u32 desc_idx)
> > {
> > struct intel_context *ce;
> > - if (unlikely(desc_idx >= guc->max_guc_ids)) {
> > + if (unlikely(desc_idx >= guc->submission_state.max_guc_ids)) {
> > drm_err(&guc_to_gt(guc)->i915->drm,
> > "Invalid desc_idx %u, max %u",
> > - desc_idx, guc->max_guc_ids);
> > + desc_idx, guc->submission_state.max_guc_ids);
> > return NULL;
> > }
> > @@ -2771,6 +2812,7 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
> > intel_context_put(ce);
> > } else if (context_destroyed(ce)) {
> > /* Context has been destroyed */
> > + intel_gt_pm_put_async(guc_to_gt(guc));
> > release_guc_id(guc, ce);
> > __guc_context_destroy(ce);
> > }
> > @@ -3065,8 +3107,10 @@ void intel_guc_submission_print_info(struct intel_guc *guc,
> > drm_printf(p, "GuC Number Outstanding Submission G2H: %u\n",
> > atomic_read(&guc->outstanding_submission_g2h));
> > - drm_printf(p, "GuC Number GuC IDs: %u\n", guc->num_guc_ids);
> > - drm_printf(p, "GuC Max GuC IDs: %u\n", guc->max_guc_ids);
> > + drm_printf(p, "GuC Number GuC IDs: %u\n",
> > + guc->submission_state.num_guc_ids);
> > + drm_printf(p, "GuC Max GuC IDs: %u\n",
> > + guc->submission_state.max_guc_ids);
> > drm_printf(p, "GuC tasklet count: %u\n\n",
> > atomic_read(&sched_engine->tasklet.count));
> >
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