[Intel-gfx] [PATCH 23/27] drm/i915/guc: Move GuC priority fields in context under guc_active
Daniele Ceraolo Spurio
daniele.ceraolospurio at intel.com
Wed Aug 25 21:51:11 UTC 2021
On 8/18/2021 11:16 PM, Matthew Brost wrote:
> Move GuC management fields in context under guc_active struct as this is
> where the lock that protects theses fields lives. Also only set guc_prio
> field once during context init.
Can you explain what we gain by setting that only on first pin? AFAICS
re-setting it doesn't hurt and we would cover the case where a context
priority gets updated while the context is idle. I know the request
submission would eventually update the prio so there is no bug, but that
then requires an extra H2G.
>
> Fixes: ee242ca704d3 ("drm/i915/guc: Implement GuC priority management")
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> Cc: <stable at vger.kernel.org>
> ---
> drivers/gpu/drm/i915/gt/intel_context_types.h | 12 ++--
> .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 68 +++++++++++--------
> drivers/gpu/drm/i915/i915_trace.h | 2 +-
> 3 files changed, 45 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> index 524a35a78bf4..9fb0480ccf3b 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> @@ -112,6 +112,7 @@ struct intel_context {
> #define CONTEXT_FORCE_SINGLE_SUBMISSION 7
> #define CONTEXT_NOPREEMPT 8
> #define CONTEXT_LRCA_DIRTY 9
> +#define CONTEXT_GUC_INIT 10
>
> struct {
> u64 timeout_us;
> @@ -178,6 +179,11 @@ struct intel_context {
> spinlock_t lock;
> /** requests: active requests on this context */
> struct list_head requests;
> + /*
> + * GuC priority management
> + */
> + u8 prio;
> + u32 prio_count[GUC_CLIENT_PRIORITY_NUM];
> } guc_active;
>
> /* GuC LRC descriptor ID */
> @@ -191,12 +197,6 @@ struct intel_context {
> */
> struct list_head guc_id_link;
>
> - /*
> - * GuC priority management
> - */
> - u8 guc_prio;
> - u32 guc_prio_count[GUC_CLIENT_PRIORITY_NUM];
> -
> #ifdef CONFIG_DRM_I915_SELFTEST
> /**
> * @drop_schedule_enable: Force drop of schedule enable G2H for selftest
> 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 3e90985b0c1b..bb90bedb1305 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -1369,8 +1369,6 @@ static void guc_context_policy_init(struct intel_engine_cs *engine,
> desc->preemption_timeout = engine->props.preempt_timeout_ms * 1000;
> }
>
> -static inline u8 map_i915_prio_to_guc_prio(int prio);
> -
> static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
> {
> struct intel_engine_cs *engine = ce->engine;
> @@ -1378,8 +1376,6 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
> struct intel_guc *guc = &engine->gt->uc.guc;
> u32 desc_idx = ce->guc_id;
> struct guc_lrc_desc *desc;
> - const struct i915_gem_context *ctx;
> - int prio = I915_CONTEXT_DEFAULT_PRIORITY;
> bool context_registered;
> intel_wakeref_t wakeref;
> int ret = 0;
> @@ -1396,12 +1392,6 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
>
> context_registered = lrc_desc_registered(guc, desc_idx);
>
> - rcu_read_lock();
> - ctx = rcu_dereference(ce->gem_context);
> - if (ctx)
> - prio = ctx->sched.priority;
> - rcu_read_unlock();
> -
> reset_lrc_desc(guc, desc_idx);
> set_lrc_desc_registered(guc, desc_idx, ce);
>
> @@ -1410,8 +1400,7 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
> desc->engine_submit_mask = adjust_engine_mask(engine->class,
> engine->mask);
> desc->hw_context_desc = ce->lrc.lrca;
> - ce->guc_prio = map_i915_prio_to_guc_prio(prio);
> - desc->priority = ce->guc_prio;
> + desc->priority = ce->guc_active.prio;
> desc->context_flags = CONTEXT_REGISTRATION_FLAG_KMD;
> guc_context_policy_init(engine, desc);
>
> @@ -1813,10 +1802,10 @@ static inline void guc_lrc_desc_unpin(struct intel_context *ce)
>
> static void __guc_context_destroy(struct intel_context *ce)
> {
> - GEM_BUG_ON(ce->guc_prio_count[GUC_CLIENT_PRIORITY_KMD_HIGH] ||
> - ce->guc_prio_count[GUC_CLIENT_PRIORITY_HIGH] ||
> - ce->guc_prio_count[GUC_CLIENT_PRIORITY_KMD_NORMAL] ||
> - ce->guc_prio_count[GUC_CLIENT_PRIORITY_NORMAL]);
> + GEM_BUG_ON(ce->guc_active.prio_count[GUC_CLIENT_PRIORITY_KMD_HIGH] ||
> + ce->guc_active.prio_count[GUC_CLIENT_PRIORITY_HIGH] ||
> + ce->guc_active.prio_count[GUC_CLIENT_PRIORITY_KMD_NORMAL] ||
> + ce->guc_active.prio_count[GUC_CLIENT_PRIORITY_NORMAL]);
> GEM_BUG_ON(ce->guc_state.number_committed_requests);
>
> lrc_fini(ce);
> @@ -1926,14 +1915,17 @@ static void guc_context_set_prio(struct intel_guc *guc,
>
> GEM_BUG_ON(prio < GUC_CLIENT_PRIORITY_KMD_HIGH ||
> prio > GUC_CLIENT_PRIORITY_NORMAL);
> + lockdep_assert_held(&ce->guc_active.lock);
>
> - if (ce->guc_prio == prio || submission_disabled(guc) ||
> - !context_registered(ce))
> + if (ce->guc_active.prio == prio || submission_disabled(guc) ||
> + !context_registered(ce)) {
> + ce->guc_active.prio = prio;
> return;
> + }
>
> guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action), 0, true);
>
> - ce->guc_prio = prio;
> + ce->guc_active.prio = prio;
> trace_intel_context_set_prio(ce);
> }
>
> @@ -1953,24 +1945,24 @@ static inline void add_context_inflight_prio(struct intel_context *ce,
> u8 guc_prio)
> {
> lockdep_assert_held(&ce->guc_active.lock);
> - GEM_BUG_ON(guc_prio >= ARRAY_SIZE(ce->guc_prio_count));
> + GEM_BUG_ON(guc_prio >= ARRAY_SIZE(ce->guc_active.prio_count));
>
> - ++ce->guc_prio_count[guc_prio];
> + ++ce->guc_active.prio_count[guc_prio];
>
> /* Overflow protection */
> - GEM_WARN_ON(!ce->guc_prio_count[guc_prio]);
> + GEM_WARN_ON(!ce->guc_active.prio_count[guc_prio]);
> }
>
> static inline void sub_context_inflight_prio(struct intel_context *ce,
> u8 guc_prio)
> {
> lockdep_assert_held(&ce->guc_active.lock);
> - GEM_BUG_ON(guc_prio >= ARRAY_SIZE(ce->guc_prio_count));
> + GEM_BUG_ON(guc_prio >= ARRAY_SIZE(ce->guc_active.prio_count));
>
> /* Underflow protection */
> - GEM_WARN_ON(!ce->guc_prio_count[guc_prio]);
> + GEM_WARN_ON(!ce->guc_active.prio_count[guc_prio]);
>
> - --ce->guc_prio_count[guc_prio];
> + --ce->guc_active.prio_count[guc_prio];
> }
>
> static inline void update_context_prio(struct intel_context *ce)
> @@ -1983,8 +1975,8 @@ static inline void update_context_prio(struct intel_context *ce)
>
> lockdep_assert_held(&ce->guc_active.lock);
>
> - for (i = 0; i < ARRAY_SIZE(ce->guc_prio_count); ++i) {
> - if (ce->guc_prio_count[i]) {
> + for (i = 0; i < ARRAY_SIZE(ce->guc_active.prio_count); ++i) {
> + if (ce->guc_active.prio_count[i]) {
> guc_context_set_prio(guc, ce, i);
> break;
> }
> @@ -2123,6 +2115,20 @@ static bool context_needs_register(struct intel_context *ce, bool new_guc_id)
> !submission_disabled(ce_to_guc(ce));
> }
>
> +static void guc_context_init(struct intel_context *ce)
> +{
> + const struct i915_gem_context *ctx;
> + int prio = I915_CONTEXT_DEFAULT_PRIORITY;
> +
> + rcu_read_lock();
> + ctx = rcu_dereference(ce->gem_context);
> + if (ctx)
> + prio = ctx->sched.priority;
> + rcu_read_unlock();
> +
> + ce->guc_active.prio = map_i915_prio_to_guc_prio(prio);
> +}
> +
> static int guc_request_alloc(struct i915_request *rq)
> {
> struct intel_context *ce = rq->context;
> @@ -2154,6 +2160,9 @@ static int guc_request_alloc(struct i915_request *rq)
>
> rq->reserved_space -= GUC_REQUEST_SIZE;
>
> + if (unlikely(!test_bit(CONTEXT_GUC_INIT, &ce->flags)))
Where is CONTEXT_GUC_INIT set? Can't find it
Daniele
> + guc_context_init(ce);
> +
> /*
> * Call pin_guc_id here rather than in the pinning step as with
> * dma_resv, contexts can be repeatedly pinned / unpinned trashing the
> @@ -3031,13 +3040,12 @@ static inline void guc_log_context_priority(struct drm_printer *p,
> {
> int i;
>
> - drm_printf(p, "\t\tPriority: %d\n",
> - ce->guc_prio);
> + drm_printf(p, "\t\tPriority: %d\n", ce->guc_active.prio);
> drm_printf(p, "\t\tNumber Requests (lower index == higher priority)\n");
> for (i = GUC_CLIENT_PRIORITY_KMD_HIGH;
> i < GUC_CLIENT_PRIORITY_NUM; ++i) {
> drm_printf(p, "\t\tNumber requests in priority band[%d]: %d\n",
> - i, ce->guc_prio_count[i]);
> + i, ce->guc_active.prio_count[i]);
> }
> drm_printf(p, "\n");
> }
> diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
> index 0a77eb2944b5..6f882e72ed11 100644
> --- a/drivers/gpu/drm/i915/i915_trace.h
> +++ b/drivers/gpu/drm/i915/i915_trace.h
> @@ -910,7 +910,7 @@ DECLARE_EVENT_CLASS(intel_context,
> __entry->guc_id = ce->guc_id;
> __entry->pin_count = atomic_read(&ce->pin_count);
> __entry->sched_state = ce->guc_state.sched_state;
> - __entry->guc_prio = ce->guc_prio;
> + __entry->guc_prio = ce->guc_active.prio;
> ),
>
> TP_printk("guc_id=%d, pin_count=%d sched_state=0x%x, guc_prio=%u",
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