Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> writes:
> To further enchance port processing, keep track of
> reserved ports. This way we can iterate only the used subset
> of port space. Note that we lift the responsibility of
> execlists_submit_request() to inspect hw availability and
s/execlist_submit_request/insert_request.
-Mika
> always do dequeuing. This is to ensure that only the irq
> handler will be responsible for keeping track of available ports.
>
> v2: rebase, comment fix, READ_ONCE only outside of irq handler (Chris)
>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Michał Winiarski <michal.winiarski@xxxxxxxxx>
> Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_guc_submission.c | 51 +++++++++--------
> drivers/gpu/drm/i915/i915_irq.c | 2 +-
> drivers/gpu/drm/i915/intel_engine_cs.c | 7 ++-
> drivers/gpu/drm/i915/intel_lrc.c | 90 ++++++++++++++++++------------
> drivers/gpu/drm/i915/intel_ringbuffer.h | 55 +++++++++++++-----
> 5 files changed, 129 insertions(+), 76 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
> index 25c9bac94c39..359f57a59cba 100644
> --- a/drivers/gpu/drm/i915/i915_guc_submission.c
> +++ b/drivers/gpu/drm/i915/i915_guc_submission.c
> @@ -487,7 +487,7 @@ static void guc_ring_doorbell(struct i915_guc_client *client)
> * @engine: engine associated with the commands
> *
> * The only error here arises if the doorbell hardware isn't functioning
> - * as expected, which really shouln't happen.
> + * as expected, which really shouldn't happen.
> */
> static void i915_guc_submit(struct intel_engine_cs *engine)
> {
> @@ -495,17 +495,19 @@ static void i915_guc_submit(struct intel_engine_cs *engine)
> struct intel_guc *guc = &dev_priv->guc;
> struct i915_guc_client *client = guc->execbuf_client;
> struct intel_engine_execlist * const el = &engine->execlist;
> - struct execlist_port *port = el->port;
> const unsigned int engine_id = engine->id;
> unsigned int n;
>
> - for (n = 0; n < ARRAY_SIZE(el->port); n++) {
> + for (n = 0; n < execlist_active_ports(el); n++) {
> + struct execlist_port *port;
> struct drm_i915_gem_request *rq;
> unsigned int count;
>
> - rq = port_unpack(&port[n], &count);
> + port = execlist_port_index(el, n);
> +
> + rq = port_unpack(port, &count);
> if (rq && count == 0) {
> - port_set(&port[n], port_pack(rq, ++count));
> + port_set(port, port_pack(rq, ++count));
>
> if (i915_vma_is_map_and_fenceable(rq->ring->vma))
> POSTING_READ_FW(GUC_STATUS);
> @@ -560,25 +562,27 @@ static void port_assign(struct execlist_port *port,
> static void i915_guc_dequeue(struct intel_engine_cs *engine)
> {
> struct intel_engine_execlist * const el = &engine->execlist;
> - struct execlist_port *port = el->port;
> + struct execlist_port *port;
> struct drm_i915_gem_request *last = NULL;
> - const struct execlist_port * const last_port = execlist_port_tail(el);
> bool submit = false;
> struct rb_node *rb;
>
> - if (port_isset(port))
> - port++;
> -
> spin_lock_irq(&engine->timeline->lock);
> rb = el->first;
> GEM_BUG_ON(rb_first(&el->queue) != rb);
> - while (rb) {
> +
> + if (unlikely(!rb))
> + goto done;
> +
> + port = execlist_request_port(el);
> +
> + do {
> struct i915_priolist *p = rb_entry(rb, typeof(*p), node);
> struct drm_i915_gem_request *rq, *rn;
>
> list_for_each_entry_safe(rq, rn, &p->requests, priotree.link) {
> if (last && rq->ctx != last->ctx) {
> - if (port == last_port) {
> + if (!execlist_inactive_ports(el)) {
> __list_del_many(&p->requests,
> &rq->priotree.link);
> goto done;
> @@ -587,7 +591,8 @@ static void i915_guc_dequeue(struct intel_engine_cs *engine)
> if (submit)
> port_assign(port, last);
>
> - port = execlist_port_next(el, port);
> + port = execlist_request_port(el);
> + GEM_BUG_ON(port_isset(port));
> }
>
> INIT_LIST_HEAD(&rq->priotree.link);
> @@ -604,7 +609,7 @@ static void i915_guc_dequeue(struct intel_engine_cs *engine)
> INIT_LIST_HEAD(&p->requests);
> if (p->priority != I915_PRIORITY_NORMAL)
> kmem_cache_free(engine->i915->priorities, p);
> - }
> + } while (rb);
> done:
> el->first = rb;
> if (submit) {
> @@ -618,21 +623,21 @@ static void i915_guc_irq_handler(unsigned long data)
> {
> struct intel_engine_cs * const engine = (struct intel_engine_cs *)data;
> struct intel_engine_execlist * const el = &engine->execlist;
> - struct execlist_port *port = execlist_port_head(el);
> - const struct execlist_port * const last_port = execlist_port_tail(el);
> - struct drm_i915_gem_request *rq;
>
> - rq = port_request(port);
> - while (rq && i915_gem_request_completed(rq)) {
> + while (execlist_active_ports(el)) {
> + struct execlist_port *port = execlist_port_head(el);
> + struct drm_i915_gem_request *rq = port_request(port);
> +
> + if (!i915_gem_request_completed(rq))
> + break;
> +
> trace_i915_gem_request_out(rq);
> i915_gem_request_put(rq);
>
> - port = execlist_port_complete(el, port);
> -
> - rq = port_request(port);
> + execlist_release_port(el, port);
> }
>
> - if (!port_isset(last_port))
> + if (execlist_inactive_ports(el))
> i915_guc_dequeue(engine);
> }
>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index ac5a95439393..a9d888b726c4 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -1342,7 +1342,7 @@ gen8_cs_irq_handler(struct intel_engine_cs *engine, u32 iir, int test_shift)
> bool tasklet = false;
>
> if (iir & (GT_CONTEXT_SWITCH_INTERRUPT << test_shift)) {
> - if (port_count(execlist_port_head(el))) {
> + if (READ_ONCE(el->port_count)) {
> __set_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
> tasklet = true;
> }
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index b0d702063a50..29b170fdd6ef 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -407,6 +407,9 @@ static void intel_engine_init_execlist(struct intel_engine_cs *engine)
> BUILD_BUG_ON_NOT_POWER_OF_2(execlist_num_ports(&engine->execlist));
> GEM_BUG_ON(execlist_num_ports(&engine->execlist) > EXECLIST_MAX_PORTS);
>
> + el->port_head = 0;
> + el->port_count = 0;
> +
> el->queue = RB_ROOT;
> el->first = NULL;
> }
> @@ -1501,8 +1504,8 @@ bool intel_engine_is_idle(struct intel_engine_cs *engine)
> if (test_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted))
> return false;
>
> - /* Both ports drained, no more ELSP submission? */
> - if (port_request(execlist_port_head(&engine->execlist)))
> + /* All ports drained, no more ELSP submission? */
> + if (execlist_active_ports(&engine->execlist))
> return false;
>
> /* ELSP is empty, but there are ready requests? */
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 8550cd6635c9..bea10620bed2 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -399,26 +399,29 @@ static void execlists_submit_ports(struct intel_engine_cs *engine)
> engine->i915->regs + i915_mmio_reg_offset(RING_ELSP(engine));
> unsigned int n;
>
> - for (n = execlist_num_ports(el); n--; ) {
> - struct execlist_port *port;
> + for (n = 0; n < execlist_inactive_ports(el); n++) {
> + writel(0, elsp);
> + writel(0, elsp);
> + }
> +
> + for (n = execlist_active_ports(el); n--; ) {
> struct drm_i915_gem_request *rq;
> + struct execlist_port *port;
> unsigned int count;
> u64 desc;
>
> port = execlist_port_index(el, n);
> -
> rq = port_unpack(port, &count);
> - if (rq) {
> - GEM_BUG_ON(count > !n);
> - if (!count++)
> - execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_IN);
> - port_set(port, port_pack(rq, count));
> - desc = execlists_update_context(rq);
> - GEM_DEBUG_EXEC(port->context_id = upper_32_bits(desc));
> - } else {
> - GEM_BUG_ON(!n);
> - desc = 0;
> - }
> +
> + GEM_BUG_ON(!rq);
> + GEM_BUG_ON(count > !n);
> +
> + if (!count++)
> + execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_IN);
> +
> + port_set(port, port_pack(rq, count));
> + desc = execlists_update_context(rq);
> + GEM_DEBUG_EXEC(port->context_id = upper_32_bits(desc));
>
> writel(upper_32_bits(desc), elsp);
> writel(lower_32_bits(desc), elsp);
> @@ -456,15 +459,23 @@ static void port_assign(struct execlist_port *port,
>
> static void execlists_dequeue(struct intel_engine_cs *engine)
> {
> - struct drm_i915_gem_request *last;
> struct intel_engine_execlist * const el = &engine->execlist;
> - struct execlist_port *port = execlist_port_head(el);
> - const struct execlist_port * const last_port = execlist_port_tail(el);
> + struct execlist_port *port;
> + struct drm_i915_gem_request *last;
> struct rb_node *rb;
> bool submit = false;
>
> - last = port_request(port);
> - if (last)
> + spin_lock_irq(&engine->timeline->lock);
> + rb = el->first;
> + GEM_BUG_ON(rb_first(&el->queue) != rb);
> +
> + if (unlikely(!rb))
> + goto done;
> +
> + if (execlist_active_ports(el)) {
> + port = execlist_port_tail(el);
> + last = port_request(port);
> +
> /* WaIdleLiteRestore:bdw,skl
> * Apply the wa NOOPs to prevent ring:HEAD == req:TAIL
> * as we resubmit the request. See gen8_emit_breadcrumb()
> @@ -472,6 +483,11 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
> * request.
> */
> last->tail = last->wa_tail;
> + } else {
> + /* Allocate first port to coalesce into */
> + port = execlist_request_port(el);
> + last = NULL;
> + }
>
> /* Hardware submission is through 2 ports. Conceptually each port
> * has a (RING_START, RING_HEAD, RING_TAIL) tuple. RING_START is
> @@ -493,11 +509,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
> * sequence of requests as being the most optimal (fewest wake ups
> * and context switches) submission.
> */
> -
> - spin_lock_irq(&engine->timeline->lock);
> - rb = el->first;
> - GEM_BUG_ON(rb_first(&el->queue) != rb);
> - while (rb) {
> + do {
> struct i915_priolist *p = rb_entry(rb, typeof(*p), node);
> struct drm_i915_gem_request *rq, *rn;
>
> @@ -515,11 +527,11 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
> */
> if (last && !can_merge_ctx(rq->ctx, last->ctx)) {
> /*
> - * If we are on the second port and cannot
> + * If we are on the last port and cannot
> * combine this request with the last, then we
> * are done.
> */
> - if (port == last_port) {
> + if (!execlist_inactive_ports(el)) {
> __list_del_many(&p->requests,
> &rq->priotree.link);
> goto done;
> @@ -544,8 +556,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
> if (submit)
> port_assign(port, last);
>
> - port = execlist_port_next(el, port);
> -
> + port = execlist_request_port(el);
> GEM_BUG_ON(port_isset(port));
> }
>
> @@ -563,7 +574,8 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
> INIT_LIST_HEAD(&p->requests);
> if (p->priority != I915_PRIORITY_NORMAL)
> kmem_cache_free(engine->i915->priorities, p);
> - }
> + } while (rb);
> +
> done:
> el->first = rb;
> if (submit)
> @@ -582,6 +594,9 @@ static void execlist_cancel_port_requests(struct intel_engine_execlist *el)
> i915_gem_request_put(port_request(&el->port[i]));
>
> memset(el->port, 0, sizeof(el->port));
> +
> + el->port_count = 0;
> + el->port_head = 0;
> }
>
> static void execlists_cancel_requests(struct intel_engine_cs *engine)
> @@ -643,10 +658,12 @@ static void execlists_cancel_requests(struct intel_engine_cs *engine)
>
> static bool execlists_elsp_ready(struct intel_engine_execlist * const el)
> {
> - struct execlist_port * const port0 = execlist_port_head(el);
> - struct execlist_port * const port1 = execlist_port_next(el, port0);
> + const unsigned int active = execlist_active_ports(el);
> +
> + if (!active)
> + return true;
>
> - return port_count(port0) + port_count(port1) < 2;
> + return port_count(execlist_port_tail(el)) + active < 2;
> }
>
> /*
> @@ -657,7 +674,6 @@ static void intel_lrc_irq_handler(unsigned long data)
> {
> struct intel_engine_cs * const engine = (struct intel_engine_cs *)data;
> struct intel_engine_execlist * const el = &engine->execlist;
> - struct execlist_port *port = execlist_port_head(el);
> struct drm_i915_private *dev_priv = engine->i915;
>
> /* We can skip acquiring intel_runtime_pm_get() here as it was taken
> @@ -714,6 +730,7 @@ static void intel_lrc_irq_handler(unsigned long data)
> }
>
> while (head != tail) {
> + struct execlist_port *port;
> struct drm_i915_gem_request *rq;
> unsigned int status;
> unsigned int count;
> @@ -742,6 +759,7 @@ static void intel_lrc_irq_handler(unsigned long data)
> if (!(status & GEN8_CTX_STATUS_COMPLETED_MASK))
> continue;
>
> + port = execlist_port_head(el);
> /* Check the context/desc id for this event matches */
> GEM_DEBUG_BUG_ON(buf[2 * head + 1] != port->context_id);
>
> @@ -755,13 +773,13 @@ static void intel_lrc_irq_handler(unsigned long data)
> trace_i915_gem_request_out(rq);
> i915_gem_request_put(rq);
>
> - port = execlist_port_complete(el, port);
> + execlist_release_port(el, port);
> } else {
> port_set(port, port_pack(rq, count));
> }
>
> /* After the final element, the hw should be idle */
> - GEM_BUG_ON(port_count(port) == 0 &&
> + GEM_BUG_ON(execlist_active_ports(el) == 0 &&
> !(status & GEN8_CTX_STATUS_ACTIVE_IDLE));
> }
>
> @@ -786,7 +804,7 @@ static void insert_request(struct intel_engine_cs *engine,
> struct i915_priolist *p = lookup_priolist(engine, pt, prio);
>
> list_add_tail(&pt->link, &ptr_mask_bits(p, 1)->requests);
> - if (ptr_unmask_bits(p, 1) && execlists_elsp_ready(el))
> + if (ptr_unmask_bits(p, 1))
> tasklet_hi_schedule(&el->irq_tasklet);
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 991f6c0bd6c2..efa5a8ea1ecb 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -249,6 +249,11 @@ struct intel_engine_execlist {
> unsigned int port_head;
>
> /**
> + * @port_count: reserved ports
> + */
> + unsigned int port_count;
> +
> + /**
> * @queue: queue of requests, in priority lists
> */
> struct rb_root queue;
> @@ -529,14 +534,20 @@ execlist_num_ports(const struct intel_engine_execlist * const el)
> return el->port_mask + 1;
> }
>
> -#define __port_idx(start, index, mask) (((start) + (index)) & (mask))
> +static inline unsigned int
> +execlist_active_ports(const struct intel_engine_execlist * const el)
> +{
> + return el->port_count;
> +}
>
> -static inline struct execlist_port *
> -execlist_port_head(struct intel_engine_execlist * const el)
> +static inline unsigned int
> +execlist_inactive_ports(const struct intel_engine_execlist * const el)
> {
> - return &el->port[el->port_head];
> + return execlist_num_ports(el) - execlist_active_ports(el);
> }
>
> +#define __port_idx(start, index, mask) (((start) + (index)) & (mask))
> +
> /* Index starting from port_head */
> static inline struct execlist_port *
> execlist_port_index(struct intel_engine_execlist * const el,
> @@ -546,30 +557,46 @@ execlist_port_index(struct intel_engine_execlist * const el,
> }
>
> static inline struct execlist_port *
> -execlist_port_tail(struct intel_engine_execlist * const el)
> +execlist_port_head(struct intel_engine_execlist * const el)
> {
> - return &el->port[__port_idx(el->port_head, -1, el->port_mask)];
> + GEM_BUG_ON(!el->port_count);
> +
> + return execlist_port_index(el, 0);
> }
>
> static inline struct execlist_port *
> -execlist_port_next(struct intel_engine_execlist * const el,
> - const struct execlist_port * const port)
> +execlist_port_tail(struct intel_engine_execlist * const el)
> {
> - const unsigned int i = port_index(port, el);
> + GEM_BUG_ON(!el->port_count);
>
> - return &el->port[__port_idx(i, 1, el->port_mask)];
> + return execlist_port_index(el, el->port_count - 1);
> }
>
> static inline struct execlist_port *
> -execlist_port_complete(struct intel_engine_execlist * const el,
> - struct execlist_port * const port)
> +execlist_request_port(struct intel_engine_execlist * const el)
> {
> + GEM_BUG_ON(el->port_count == el->port_mask + 1);
> +
> + el->port_count++;
> +
> + GEM_BUG_ON(port_isset(execlist_port_tail(el)));
> +
> + return execlist_port_tail(el);
> +}
> +
> +static inline void
> +execlist_release_port(struct intel_engine_execlist * const el,
> + struct execlist_port * const port)
> +{
> +
> GEM_BUG_ON(port_index(port, el) != el->port_head);
> + GEM_BUG_ON(!port_isset(port));
> + GEM_BUG_ON(!el->port_count);
>
> memset(port, 0, sizeof(struct execlist_port));
> - el->port_head = __port_idx(el->port_head, 1, el->port_mask);
>
> - return execlist_port_head(el);
> + el->port_head = __port_idx(el->port_head, 1, el->port_mask);
> + el->port_count--;
> }
>
> static inline unsigned int
> --
> 2.11.0
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