[Intel-gfx] [PATCH 07/46] drm/i915/guc: Non-static lrc descriptor registration buffer

Matthew Brost
2021-08-03T22:12:11Z

Dynamically allocate space for lrc descriptor registration with the GuC
rather than using a large static buffer indexed by the guc_id. If no
space is available to register a context, fall back to tasklet flow
control mechanism. Only allow 1/2 of the space to be allocated outside
the tasklet to prevent unready requests/contexts from consuming all
registration space.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
drivers/gpu/drm/i915/gt/intel_context_types.h | 3 +
drivers/gpu/drm/i915/gt/uc/intel_guc.h | 9 +-
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 202 ++++++++++++------
3 files changed, 150 insertions(+), 64 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index c01530d7dc67..2df79ba39867 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -179,6 +179,9 @@ struct intel_context {
/* GuC scheduling state flags that do not require a lock. */
atomic_t guc_sched_state_no_lock;

+ /* GuC lrc descriptor registration buffer */
+ unsigned int guc_lrcd_reg_idx;
+
/* GuC LRC descriptor ID */
u16 guc_id;

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index 8ac016201658..c0a12ae95ba5 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -69,8 +69,13 @@ struct intel_guc {
u32 ads_regset_size;
u32 ads_golden_ctxt_size;

- struct i915_vma *lrc_desc_pool;
- void *lrc_desc_pool_vaddr;
+ /* GuC LRC descriptor registration */
+ struct {
+ struct i915_vma *vma;
+ void *vaddr;
+ struct ida ida;
+ unsigned int max_idx;
+ } lrcd_reg;

/* guc_id to intel_context lookup */
struct xarray context_lookup;
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 a7f7174b5343..bfda15bf9182 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -439,65 +439,54 @@ static inline struct i915_priolist *to_priolist(struct rb_node *rb)
return rb_entry(rb, struct i915_priolist, node);
}

-static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, u32 index)
+static u32 __get_lrc_desc_offset(struct intel_guc *guc, int index)
{
- struct guc_lrc_desc *base = guc->lrc_desc_pool_vaddr;
-
+ GEM_BUG_ON(index >= guc->lrcd_reg.max_idx);
GEM_BUG_ON(index >= guc->max_guc_ids);

- return &base[index];
+ return intel_guc_ggtt_offset(guc, guc->lrcd_reg.vma) +
+ (index * sizeof(struct guc_lrc_desc));
}

-static inline struct intel_context *__get_context(struct intel_guc *guc, u32 id)
+static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, int index)
{
- struct intel_context *ce = xa_load(&guc->context_lookup, id);
+ struct guc_lrc_desc *desc;

- GEM_BUG_ON(id >= guc->max_guc_ids);
+ GEM_BUG_ON(index >= guc->lrcd_reg.max_idx);
+ GEM_BUG_ON(index >= guc->max_guc_ids);

- return ce;
+ desc = guc->lrcd_reg.vaddr;
+ desc = &desc[index];
+ memset(desc, 0, sizeof(*desc));
+
+ return desc;
}

-static int guc_lrc_desc_pool_create(struct intel_guc *guc)
+static inline struct intel_context *__get_context(struct intel_guc *guc, u32 id)
{
- u32 size;
- int ret;
-
- size = PAGE_ALIGN(sizeof(struct guc_lrc_desc) * guc->max_guc_ids);
- ret = intel_guc_allocate_and_map_vma(guc, size, &guc->lrc_desc_pool,
- (void **)&guc->lrc_desc_pool_vaddr);
- if (ret)
- return ret;
+ struct intel_context *ce = xa_load(&guc->context_lookup, id);

- return 0;
-}
+ GEM_BUG_ON(id >= guc->max_guc_ids);

-static void guc_lrc_desc_pool_destroy(struct intel_guc *guc)
-{
- guc->lrc_desc_pool_vaddr = NULL;
- i915_vma_unpin_and_release(&guc->lrc_desc_pool, I915_VMA_RELEASE_MAP);
+ return ce;
}

static inline bool guc_submission_initialized(struct intel_guc *guc)
{
- return !!guc->lrc_desc_pool_vaddr;
+ return !!guc->lrcd_reg.max_idx;
}

-static inline void reset_lrc_desc(struct intel_guc *guc, u32 id)
+static inline void clr_lrc_desc_registered(struct intel_guc *guc, u32 id)
{
- if (likely(guc_submission_initialized(guc))) {
- struct guc_lrc_desc *desc = __get_lrc_desc(guc, id);
- unsigned long flags;
-
- memset(desc, 0, sizeof(*desc));
+ unsigned long flags;

- /*
- * xarray API doesn't have xa_erase_irqsave wrapper, so calling
- * the lower level functions directly.
- */
- xa_lock_irqsave(&guc->context_lookup, flags);
- __xa_erase(&guc->context_lookup, id);
- xa_unlock_irqrestore(&guc->context_lookup, flags);
- }
+ /*
+ * xarray API doesn't have xa_erase_irqsave wrapper, so calling
+ * the lower level functions directly.
+ */
+ xa_lock_irqsave(&guc->context_lookup, flags);
+ __xa_erase(&guc->context_lookup, id);
+ xa_unlock_irqrestore(&guc->context_lookup, flags);
}

static inline bool lrc_desc_registered(struct intel_guc *guc, u32 id)
@@ -1385,6 +1374,9 @@ static void retire_worker_func(struct work_struct *w)
}
}

+static int guc_lrcd_reg_init(struct intel_guc *guc);
+static void guc_lrcd_reg_fini(struct intel_guc *guc);
+
/*
* Set up the memory resources to be shared with the GuC (via the GGTT)
* at firmware loading time.
@@ -1393,17 +1385,12 @@ int intel_guc_submission_init(struct intel_guc *guc)
{
int ret;

- if (guc->lrc_desc_pool)
+ if (guc_submission_initialized(guc))
return 0;

- ret = guc_lrc_desc_pool_create(guc);
+ ret = guc_lrcd_reg_init(guc);
if (ret)
return ret;
- /*
- * Keep static analysers happy, let them know that we allocated the
- * vma after testing that it didn't exist earlier.
- */
- GEM_BUG_ON(!guc->lrc_desc_pool);

xa_init_flags(&guc->context_lookup, XA_FLAGS_LOCK_IRQ);

@@ -1419,10 +1406,10 @@ void intel_guc_submission_fini(struct intel_guc *guc)
{
int i;

- if (!guc->lrc_desc_pool)
+ if (!guc_submission_initialized(guc))
return;

- guc_lrc_desc_pool_destroy(guc);
+ guc_lrcd_reg_fini(guc);

for (i = 0; i < GUC_SUBMIT_ENGINE_MAX; ++i) {
struct i915_sched_engine *sched_engine =
@@ -1495,6 +1482,7 @@ static bool need_tasklet(struct guc_submit_engine *gse, struct intel_context *ce
return guc_ids_exhausted(gse) || submission_disabled(guc) ||
gse->stalled_rq || gse->stalled_context ||
!lrc_desc_registered(guc, ce->guc_id) ||
+ context_needs_register(ce) ||
!i915_sched_engine_is_empty(sched_engine);
}

@@ -1546,7 +1534,7 @@ 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);
- reset_lrc_desc(guc, ce->guc_id);
+ clr_lrc_desc_registered(guc, ce->guc_id);
set_context_guc_id_invalid(ce);
}
if (!list_empty(&ce->guc_id_link))
@@ -1743,14 +1731,14 @@ static void unpin_guc_id(struct intel_guc *guc,
}

static int __guc_action_register_context(struct intel_guc *guc,
+ struct intel_context *ce,
u32 guc_id,
- u32 offset,
bool loop)
{
u32 action[] = {
INTEL_GUC_ACTION_REGISTER_CONTEXT,
guc_id,
- offset,
+ __get_lrc_desc_offset(guc, ce->guc_lrcd_reg_idx),
};

return guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action),
@@ -1760,13 +1748,11 @@ static int __guc_action_register_context(struct intel_guc *guc,
static int register_context(struct intel_context *ce, bool loop)
{
struct intel_guc *guc = ce_to_guc(ce);
- u32 offset = intel_guc_ggtt_offset(guc, guc->lrc_desc_pool) +
- ce->guc_id * sizeof(struct guc_lrc_desc);
int ret;

trace_intel_context_register(ce);

- ret = __guc_action_register_context(guc, ce->guc_id, offset, loop);
+ ret = __guc_action_register_context(guc, ce, ce->guc_id, loop);
if (likely(!ret))
set_context_registered(ce);

@@ -1828,6 +1814,86 @@ static void guc_context_policy_init(struct intel_engine_cs *engine,

static inline u8 map_i915_prio_to_guc_prio(int prio);

+static int alloc_lrcd_reg_idx_buffer(struct intel_guc *guc, int num_per_vma)
+{
+ u32 size = num_per_vma * sizeof(struct guc_lrc_desc);
+ struct i915_vma **vma = &guc->lrcd_reg.vma;
+ void **vaddr = &guc->lrcd_reg.vaddr;
+ int ret;
+
+ GEM_BUG_ON(!is_power_of_2(size));
+
+ ret = intel_guc_allocate_and_map_vma(guc, size, vma, vaddr);
+ if (unlikely(ret))
+ return ret;
+
+ guc->lrcd_reg.max_idx += num_per_vma;
+
+ return 0;
+}
+
+static int alloc_lrcd_reg_idx(struct intel_guc *guc, bool tasklet)
+{
+ int ret;
+ gfp_t gfp = tasklet ? GFP_ATOMIC :
+ GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
+
+ might_sleep_if(!tasklet);
+
+ /*
+ * We only allow 1/2 of the space to be allocated outside of tasklet
+ * (flow control) to ensure requests that are not ready don't consume
+ * all context registration space.
+ */
+ ret = ida_simple_get(&guc->lrcd_reg.ida, 0,
+ tasklet ? guc->lrcd_reg.max_idx :
+ guc->lrcd_reg.max_idx / 2, gfp);
+ if (unlikely(ret < 0))
+ return -EBUSY;
+
+ return ret;
+}
+
+static void __free_lrcd_reg_idx(struct intel_guc *guc, struct intel_context *ce)
+{
+ if (ce->guc_lrcd_reg_idx && guc->lrcd_reg.max_idx) {
+ ida_simple_remove(&guc->lrcd_reg.ida, ce->guc_lrcd_reg_idx);
+ ce->guc_lrcd_reg_idx = 0;
+ }
+}
+
+static void free_lrcd_reg_idx(struct intel_guc *guc, struct intel_context *ce)
+{
+ __free_lrcd_reg_idx(guc, ce);
+}
+
+static int guc_lrcd_reg_init(struct intel_guc *guc)
+{
+ unsigned int buffer_size = I915_GTT_PAGE_SIZE_4K * 16;
+ int ret;
+
+ ida_init(&guc->lrcd_reg.ida);
+
+ ret = alloc_lrcd_reg_idx_buffer(guc, buffer_size /
+ sizeof(struct guc_lrc_desc));
+ if (unlikely(ret))
+ return ret;
+
+ /* Zero is reserved */
+ ret = alloc_lrcd_reg_idx(guc, false);
+ GEM_BUG_ON(ret);
+
+ return ret;
+}
+
+static void guc_lrcd_reg_fini(struct intel_guc *guc)
+{
+ i915_vma_unpin_and_release(&guc->lrcd_reg.vma,
+ I915_VMA_RELEASE_MAP);
+ ida_destroy(&guc->lrcd_reg.ida);
+ guc->lrcd_reg.max_idx = 0;
+}
+
static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
{
struct intel_engine_cs *engine = ce->engine;
@@ -1851,6 +1917,14 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) !=
i915_gem_object_is_lmem(ce->ring->vma->obj));

+ /* Allocate space for registration */
+ if (likely(!ce->guc_lrcd_reg_idx)) {
+ ret = alloc_lrcd_reg_idx(guc, !loop);
+ if (unlikely(ret < 0))
+ return ret;
+ ce->guc_lrcd_reg_idx = ret;
+ }
+
context_registered = lrc_desc_registered(guc, desc_idx);

rcu_read_lock();
@@ -1859,12 +1933,11 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
prio = ctx->sched.priority;
rcu_read_unlock();

- reset_lrc_desc(guc, desc_idx);
ret = set_lrc_desc_registered(guc, desc_idx, ce);
if (unlikely(ret))
return ret;

- desc = __get_lrc_desc(guc, desc_idx);
+ desc = __get_lrc_desc(guc, ce->guc_lrcd_reg_idx);
desc->engine_class = engine_class_to_guc_class(engine->class);
desc->engine_submit_mask = adjust_engine_mask(engine->class,
engine->mask);
@@ -1902,7 +1975,7 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
}
spin_unlock_irqrestore(&ce->guc_state.lock, flags);
if (unlikely(disabled)) {
- reset_lrc_desc(guc, desc_idx);
+ clr_lrc_desc_registered(guc, desc_idx);
return 0; /* Will get registered later */
}
}
@@ -1930,7 +2003,7 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
with_intel_runtime_pm(runtime_pm, wakeref)
ret = register_context(ce, loop);
if (unlikely(ret == -EBUSY))
- reset_lrc_desc(guc, desc_idx);
+ clr_lrc_desc_registered(guc, desc_idx);
else if (unlikely(ret == -ENODEV))
ret = 0; /* Will get registered later */
}
@@ -2296,6 +2369,7 @@ static void __guc_context_destroy(struct intel_context *ce)

lrc_fini(ce);
intel_context_fini(ce);
+ __free_lrcd_reg_idx(ce_to_guc(ce), ce);

if (intel_engine_is_virtual(ce->engine)) {
struct guc_virtual_engine *ve =
@@ -2807,11 +2881,11 @@ static int guc_request_alloc(struct i915_request *rq)

if (context_needs_lrc_desc_pin(ce, !!ret)) {
ret = guc_lrc_desc_pin(ce, true);
- if (unlikely(ret)) { /* unwind */
- if (ret == -EPIPE) {
- disable_submission(guc);
- goto out; /* GPU will be reset */
- }
+ if (unlikely(ret == -EBUSY))
+ set_context_needs_register(ce);
+ else if (ret == -EPIPE)
+ disable_submission(guc); /* GPU will be reset */
+ else if (unlikely(ret)) { /* unwind */
atomic_dec(&ce->guc_id_ref);
unpin_guc_id(guc, ce, true);
return ret;
@@ -3438,6 +3512,8 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,

if (context_pending_enable(ce)) {
clr_context_pending_enable(ce);
+
+ free_lrcd_reg_idx(guc, ce);
} else if (context_pending_disable(ce)) {
bool banned;

@@ -3706,6 +3782,8 @@ void intel_guc_submission_print_info(struct intel_guc *guc,
atomic_read(&guc->outstanding_submission_g2h));
drm_printf(p, "GuC Number GuC IDs: %d\n", guc->num_guc_ids);
drm_printf(p, "GuC Max Number GuC IDs: %d\n\n", guc->max_guc_ids);
+ drm_printf(p, "GuC max context registered: %u\n\n",
+ guc->lrcd_reg.max_idx);

for (i = 0; i < GUC_SUBMIT_ENGINE_MAX; ++i)
gse_log_submission_info(guc->gse[i], p, i);
--
2.28.0