[PATCH v3 3/5] drm/xe: Don't initialize fences at xe_sched_job_create()
Rodrigo Vivi
rodrigo.vivi at intel.com
Fri May 24 13:12:22 UTC 2024
On Fri, May 24, 2024 at 09:19:38AM +0200, Thomas Hellström wrote:
> Pre-allocate but don't initialize fences at xe_sched_job_create(),
> and initialize / arm them instead at xe_sched_job_arm(). This
> makes it possible to move xe_sched_job_create() with its memory
> allocation out of any lock that is required for fence
> initialization, and that may not allow memory allocation under it.
>
> Replaces the struct dma_fence_array for parallell jobs with a
> struct dma_fence_chain, since the former doesn't allow
> a split-up between allocation and initialization.
I'm wondering if it would be possible/better to split this change
in a separate patch.
>
> v2:
> - Rebase.
> - Don't always use the first lrc when initializing parallel
> lrc fences.
> - Use dma_fence_chain_contained() to access the lrc fences.
>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> ---
> drivers/gpu/drm/xe/xe_exec_queue.c | 5 -
> drivers/gpu/drm/xe/xe_exec_queue_types.h | 10 --
> drivers/gpu/drm/xe/xe_ring_ops.c | 12 +-
> drivers/gpu/drm/xe/xe_sched_job.c | 159 +++++++++++++----------
> drivers/gpu/drm/xe/xe_sched_job_types.h | 18 ++-
> drivers/gpu/drm/xe/xe_trace.h | 2 +-
> 6 files changed, 113 insertions(+), 93 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c b/drivers/gpu/drm/xe/xe_exec_queue.c
> index e8bf250f5b6a..e3cebec3de24 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue.c
> +++ b/drivers/gpu/drm/xe/xe_exec_queue.c
> @@ -96,11 +96,6 @@ static struct xe_exec_queue *__xe_exec_queue_alloc(struct xe_device *xe,
> }
> }
>
> - if (xe_exec_queue_is_parallel(q)) {
> - q->parallel.composite_fence_ctx = dma_fence_context_alloc(1);
> - q->parallel.composite_fence_seqno = 0;
> - }
> -
> return q;
> }
>
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue_types.h b/drivers/gpu/drm/xe/xe_exec_queue_types.h
> index ee78d497d838..f0c40e8ad80a 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue_types.h
> +++ b/drivers/gpu/drm/xe/xe_exec_queue_types.h
> @@ -103,16 +103,6 @@ struct xe_exec_queue {
> struct xe_guc_exec_queue *guc;
> };
>
> - /**
> - * @parallel: parallel submission state
> - */
> - struct {
> - /** @parallel.composite_fence_ctx: context composite fence */
> - u64 composite_fence_ctx;
> - /** @parallel.composite_fence_seqno: seqno for composite fence */
> - u32 composite_fence_seqno;
> - } parallel;
> -
> /** @sched_props: scheduling properties */
> struct {
> /** @sched_props.timeslice_us: timeslice period in micro-seconds */
> diff --git a/drivers/gpu/drm/xe/xe_ring_ops.c b/drivers/gpu/drm/xe/xe_ring_ops.c
> index 2705d1f9d572..f75756e7a87b 100644
> --- a/drivers/gpu/drm/xe/xe_ring_ops.c
> +++ b/drivers/gpu/drm/xe/xe_ring_ops.c
> @@ -366,7 +366,7 @@ static void emit_migration_job_gen12(struct xe_sched_job *job,
>
> dw[i++] = MI_ARB_ON_OFF | MI_ARB_DISABLE; /* Enabled again below */
>
> - i = emit_bb_start(job->batch_addr[0], BIT(8), dw, i);
> + i = emit_bb_start(job->ptrs[0].batch_addr, BIT(8), dw, i);
>
> if (!IS_SRIOV_VF(gt_to_xe(job->q->gt))) {
> /* XXX: Do we need this? Leaving for now. */
> @@ -375,7 +375,7 @@ static void emit_migration_job_gen12(struct xe_sched_job *job,
> dw[i++] = preparser_disable(false);
> }
>
> - i = emit_bb_start(job->batch_addr[1], BIT(8), dw, i);
> + i = emit_bb_start(job->ptrs[1].batch_addr, BIT(8), dw, i);
>
> dw[i++] = MI_FLUSH_DW | MI_INVALIDATE_TLB | job->migrate_flush_flags |
> MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_IMM_DW;
> @@ -397,7 +397,7 @@ static void emit_job_gen12_gsc(struct xe_sched_job *job)
> xe_gt_assert(gt, job->q->width <= 1); /* no parallel submission for GSCCS */
>
> __emit_job_gen12_simple(job, job->q->lrc,
> - job->batch_addr[0],
> + job->ptrs[0].batch_addr,
> xe_sched_job_lrc_seqno(job));
> }
>
> @@ -413,7 +413,7 @@ static void emit_job_gen12_copy(struct xe_sched_job *job)
>
> for (i = 0; i < job->q->width; ++i)
> __emit_job_gen12_simple(job, job->q->lrc + i,
> - job->batch_addr[i],
> + job->ptrs[i].batch_addr,
> xe_sched_job_lrc_seqno(job));
> }
>
> @@ -424,7 +424,7 @@ static void emit_job_gen12_video(struct xe_sched_job *job)
> /* FIXME: Not doing parallel handshake for now */
> for (i = 0; i < job->q->width; ++i)
> __emit_job_gen12_video(job, job->q->lrc + i,
> - job->batch_addr[i],
> + job->ptrs[i].batch_addr,
> xe_sched_job_lrc_seqno(job));
> }
>
> @@ -434,7 +434,7 @@ static void emit_job_gen12_render_compute(struct xe_sched_job *job)
>
> for (i = 0; i < job->q->width; ++i)
> __emit_job_gen12_render_compute(job, job->q->lrc + i,
> - job->batch_addr[i],
> + job->ptrs[i].batch_addr,
> xe_sched_job_lrc_seqno(job));
> }
>
> diff --git a/drivers/gpu/drm/xe/xe_sched_job.c b/drivers/gpu/drm/xe/xe_sched_job.c
> index 874450be327e..4537c7f9099f 100644
> --- a/drivers/gpu/drm/xe/xe_sched_job.c
> +++ b/drivers/gpu/drm/xe/xe_sched_job.c
> @@ -6,7 +6,7 @@
> #include "xe_sched_job.h"
>
> #include <drm/xe_drm.h>
> -#include <linux/dma-fence-array.h>
> +#include <linux/dma-fence-chain.h>
> #include <linux/slab.h>
>
> #include "xe_device.h"
> @@ -29,7 +29,7 @@ int __init xe_sched_job_module_init(void)
> xe_sched_job_slab =
> kmem_cache_create("xe_sched_job",
> sizeof(struct xe_sched_job) +
> - sizeof(u64), 0,
> + sizeof(struct xe_job_ptrs), 0,
> SLAB_HWCACHE_ALIGN, NULL);
> if (!xe_sched_job_slab)
> return -ENOMEM;
> @@ -37,7 +37,7 @@ int __init xe_sched_job_module_init(void)
> xe_sched_job_parallel_slab =
> kmem_cache_create("xe_sched_job_parallel",
> sizeof(struct xe_sched_job) +
> - sizeof(u64) *
> + sizeof(struct xe_job_ptrs) *
> XE_HW_ENGINE_MAX_INSTANCE, 0,
> SLAB_HWCACHE_ALIGN, NULL);
> if (!xe_sched_job_parallel_slab) {
> @@ -79,26 +79,33 @@ static struct xe_device *job_to_xe(struct xe_sched_job *job)
> return gt_to_xe(job->q->gt);
> }
>
> +/* Free unused pre-allocated fences */
> +static void xe_sched_job_free_fences(struct xe_sched_job *job)
> +{
> + int i;
> +
> + for (i = 0; i < job->q->width; ++i) {
> + struct xe_job_ptrs *ptrs = &job->ptrs[i];
> +
> + if (ptrs->lrc_fence)
> + xe_lrc_free_seqno_fence(ptrs->lrc_fence);
> + if (ptrs->chain_fence)
> + dma_fence_chain_free(ptrs->chain_fence);
> + }
> +}
> +
> struct xe_sched_job *xe_sched_job_create(struct xe_exec_queue *q,
> u64 *batch_addr)
> {
> - struct xe_sched_job *job;
> - struct dma_fence **fences;
> bool is_migration = xe_sched_job_is_migration(q);
> + struct xe_sched_job *job;
> int err;
> - int i, j;
> + int i;
> u32 width;
>
> /* only a kernel context can submit a vm-less job */
> XE_WARN_ON(!q->vm && !(q->flags & EXEC_QUEUE_FLAG_KERNEL));
>
> - /* Migration and kernel engines have their own locking */
> - if (!(q->flags & (EXEC_QUEUE_FLAG_KERNEL | EXEC_QUEUE_FLAG_VM))) {
> - lockdep_assert_held(&q->vm->lock);
> - if (!xe_vm_in_lr_mode(q->vm))
> - xe_vm_assert_held(q->vm);
> - }
> -
> job = job_alloc(xe_exec_queue_is_parallel(q) || is_migration);
> if (!job)
> return ERR_PTR(-ENOMEM);
> @@ -111,43 +118,25 @@ struct xe_sched_job *xe_sched_job_create(struct xe_exec_queue *q,
> if (err)
> goto err_free;
>
> - if (!xe_exec_queue_is_parallel(q)) {
> - job->fence = xe_lrc_create_seqno_fence(q->lrc);
> - if (IS_ERR(job->fence)) {
> - err = PTR_ERR(job->fence);
> - goto err_sched_job;
> - }
> - job->lrc_seqno = job->fence->seqno;
> - } else {
> - struct dma_fence_array *cf;
> + for (i = 0; i < q->width; ++i) {
> + struct dma_fence *fence = xe_lrc_alloc_seqno_fence();
> + struct dma_fence_chain *chain;
>
> - fences = kmalloc_array(q->width, sizeof(*fences), GFP_KERNEL);
> - if (!fences) {
> - err = -ENOMEM;
> + if (IS_ERR(fence)) {
> + err = PTR_ERR(fence);
> goto err_sched_job;
> }
> + job->ptrs[i].lrc_fence = fence;
>
> - for (j = 0; j < q->width; ++j) {
> - fences[j] = xe_lrc_create_seqno_fence(q->lrc + j);
> - if (IS_ERR(fences[j])) {
> - err = PTR_ERR(fences[j]);
> - goto err_fences;
> - }
> - if (!j)
> - job->lrc_seqno = fences[0]->seqno;
> - }
> + if (i + 1 == q->width)
> + continue;
>
> - cf = dma_fence_array_create(q->width, fences,
> - q->parallel.composite_fence_ctx,
> - q->parallel.composite_fence_seqno++,
> - false);
> - if (!cf) {
> - --q->parallel.composite_fence_seqno;
> + chain = dma_fence_chain_alloc();
> + if (!chain) {
> err = -ENOMEM;
> - goto err_fences;
> + goto err_sched_job;
> }
> -
> - job->fence = &cf->base;
> + job->ptrs[i].chain_fence = chain;
> }
>
> width = q->width;
> @@ -155,19 +144,14 @@ struct xe_sched_job *xe_sched_job_create(struct xe_exec_queue *q,
> width = 2;
>
> for (i = 0; i < width; ++i)
> - job->batch_addr[i] = batch_addr[i];
> + job->ptrs[i].batch_addr = batch_addr[i];
>
> xe_pm_runtime_get_noresume(job_to_xe(job));
> trace_xe_sched_job_create(job);
> return job;
>
> -err_fences:
> - for (j = j - 1; j >= 0; --j) {
> - --q->lrc[j].fence_ctx.next_seqno;
> - dma_fence_put(fences[j]);
> - }
> - kfree(fences);
> err_sched_job:
> + xe_sched_job_free_fences(job);
> drm_sched_job_cleanup(&job->drm);
> err_free:
> xe_exec_queue_put(q);
> @@ -188,6 +172,7 @@ void xe_sched_job_destroy(struct kref *ref)
> container_of(ref, struct xe_sched_job, refcount);
> struct xe_device *xe = job_to_xe(job);
>
> + xe_sched_job_free_fences(job);
> xe_exec_queue_put(job->q);
> dma_fence_put(job->fence);
> drm_sched_job_cleanup(&job->drm);
> @@ -195,27 +180,32 @@ void xe_sched_job_destroy(struct kref *ref)
> xe_pm_runtime_put(xe);
> }
>
> -void xe_sched_job_set_error(struct xe_sched_job *job, int error)
> +/* Set the error status under the fence to avoid racing with signaling */
> +static bool xe_fence_set_error(struct dma_fence *fence, int error)
> {
> - if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &job->fence->flags))
> - return;
> + unsigned long irq_flags;
> + bool signaled;
>
> - dma_fence_set_error(job->fence, error);
> + spin_lock_irqsave(fence->lock, irq_flags);
> + signaled = test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags);
> + if (!signaled)
> + dma_fence_set_error(fence, error);
> + spin_unlock_irqrestore(fence->lock, irq_flags);
> +
> + return signaled;
> +}
>
> - if (dma_fence_is_array(job->fence)) {
> - struct dma_fence_array *array =
> - to_dma_fence_array(job->fence);
> - struct dma_fence **child = array->fences;
> - unsigned int nchild = array->num_fences;
> +void xe_sched_job_set_error(struct xe_sched_job *job, int error)
> +{
> + if (xe_fence_set_error(job->fence, error))
> + return;
>
> - do {
> - struct dma_fence *current_fence = *child++;
> + if (dma_fence_is_chain(job->fence)) {
> + struct dma_fence *iter;
>
> - if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
> - ¤t_fence->flags))
> - continue;
> - dma_fence_set_error(current_fence, error);
> - } while (--nchild);
> + dma_fence_chain_for_each(iter, job->fence)
> + xe_fence_set_error(dma_fence_chain_contained(iter),
> + error);
> }
>
> trace_xe_sched_job_set_error(job);
> @@ -230,7 +220,7 @@ bool xe_sched_job_started(struct xe_sched_job *job)
>
> return !__dma_fence_is_later(xe_sched_job_lrc_seqno(job),
> xe_lrc_start_seqno(lrc),
> - dma_fence_array_first(job->fence)->ops);
> + dma_fence_chain_contained(job->fence)->ops);
> }
>
> bool xe_sched_job_completed(struct xe_sched_job *job)
> @@ -244,13 +234,24 @@ bool xe_sched_job_completed(struct xe_sched_job *job)
>
> return !__dma_fence_is_later(xe_sched_job_lrc_seqno(job),
> xe_lrc_seqno(lrc),
> - dma_fence_array_first(job->fence)->ops);
> + dma_fence_chain_contained(job->fence)->ops);
> }
>
> void xe_sched_job_arm(struct xe_sched_job *job)
> {
> struct xe_exec_queue *q = job->q;
> + struct dma_fence *fence, *prev;
> struct xe_vm *vm = q->vm;
> + u64 seqno = 0;
> + int i;
> +
> + /* Migration and kernel engines have their own locking */
> + if (IS_ENABLED(CONFIG_LOCKDEP) &&
> + !(q->flags & (EXEC_QUEUE_FLAG_KERNEL | EXEC_QUEUE_FLAG_VM))) {
> + lockdep_assert_held(&q->vm->lock);
> + if (!xe_vm_in_lr_mode(q->vm))
> + xe_vm_assert_held(q->vm);
> + }
>
> if (vm && !xe_sched_job_is_migration(q) && !xe_vm_in_lr_mode(vm) &&
> (vm->batch_invalidate_tlb || vm->tlb_flush_seqno != q->tlb_flush_seqno)) {
> @@ -259,6 +260,25 @@ void xe_sched_job_arm(struct xe_sched_job *job)
> job->ring_ops_flush_tlb = true;
> }
>
> + /* Arm the pre-allocated fences */
> + for (i = 0; i < q->width; prev = fence, ++i) {
> + struct dma_fence_chain *chain;
> +
> + fence = job->ptrs[i].lrc_fence;
> + xe_lrc_init_seqno_fence(&q->lrc[i], fence);
> + job->ptrs[i].lrc_fence = NULL;
> + if (!i) {
> + job->lrc_seqno = fence->seqno;
same question of the first patch remains here...
> + continue;
but here my doubt goes a bit beyond on why you only init
the chain the non-first one.
> + }
> +
> + chain = job->ptrs[i - 1].chain_fence;
> + dma_fence_chain_init(chain, prev, fence, seqno++);
> + job->ptrs[i - 1].chain_fence = NULL;
> + fence = &chain->base;
> + }
> +
> + job->fence = fence;
> drm_sched_job_arm(&job->drm);
> }
>
> @@ -318,7 +338,8 @@ xe_sched_job_snapshot_capture(struct xe_sched_job *job)
>
> snapshot->batch_addr_len = q->width;
> for (i = 0; i < q->width; i++)
> - snapshot->batch_addr[i] = xe_device_uncanonicalize_addr(xe, job->batch_addr[i]);
> + snapshot->batch_addr[i] =
> + xe_device_uncanonicalize_addr(xe, job->ptrs[i].batch_addr);
>
> return snapshot;
> }
> diff --git a/drivers/gpu/drm/xe/xe_sched_job_types.h b/drivers/gpu/drm/xe/xe_sched_job_types.h
> index 990ddac55ed6..0d3f76fb05ce 100644
> --- a/drivers/gpu/drm/xe/xe_sched_job_types.h
> +++ b/drivers/gpu/drm/xe/xe_sched_job_types.h
> @@ -11,6 +11,20 @@
> #include <drm/gpu_scheduler.h>
>
> struct xe_exec_queue;
> +struct dma_fence;
> +struct dma_fence_chain;
> +
> +/**
> + * struct xe_job_ptrs - Per hw engine instance data
> + */
> +struct xe_job_ptrs {
> + /** @lrc_fence: Pre-allocated uinitialized lrc fence.*/
> + struct dma_fence *lrc_fence;
> + /** @chain_fence: Pre-allocated ninitialized fence chain node. */
> + struct dma_fence_chain *chain_fence;
> + /** @batch_addr: Batch buffer address. */
> + u64 batch_addr;
> +};
>
> /**
> * struct xe_sched_job - XE schedule job (batch buffer tracking)
> @@ -43,8 +57,8 @@ struct xe_sched_job {
> u32 migrate_flush_flags;
> /** @ring_ops_flush_tlb: The ring ops need to flush TLB before payload. */
> bool ring_ops_flush_tlb;
> - /** @batch_addr: batch buffer address of job */
> - u64 batch_addr[];
> + /** @ptrs: per instance pointers. */
> + struct xe_job_ptrs ptrs[];
instance and ptrs sounds so generic here...
I'm bad with names as well... but I'm wondering if it wouldn't be better
to s/xe_sched_job *job/xe_sched_jobs *jobs/
and then this one here is 'a' job: struct xe_job job[];
Another bad option xe_batches_and_fences batches_and_fences[]; :/
> };
>
> struct xe_sched_job_snapshot {
> diff --git a/drivers/gpu/drm/xe/xe_trace.h b/drivers/gpu/drm/xe/xe_trace.h
> index 6c6cecc58f63..450f407c66e8 100644
> --- a/drivers/gpu/drm/xe/xe_trace.h
> +++ b/drivers/gpu/drm/xe/xe_trace.h
> @@ -272,7 +272,7 @@ DECLARE_EVENT_CLASS(xe_sched_job,
> __entry->flags = job->q->flags;
> __entry->error = job->fence->error;
> __entry->fence = job->fence;
> - __entry->batch_addr = (u64)job->batch_addr[0];
> + __entry->batch_addr = (u64)job->ptrs[0].batch_addr;
> ),
>
> TP_printk("fence=%p, seqno=%u, lrc_seqno=%u, guc_id=%d, batch_addr=0x%012llx, guc_state=0x%x, flags=0x%x, error=%d",
> --
> 2.44.0
>
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