On Thu, Mar 21, 2024 at 12:37:11PM +0100, Thomas Hellström wrote:
> For each rebind we insert a GuC TLB invalidation and add a
> corresponding unordered TLB invalidation fence. This might
> add a huge number of TLB invalidation fences to wait for so
> rather than doing that, defer the TLB invalidation to the
> next ring ops for each affected exec queue. Since the TLB
> is invalidated on exec_queue switch, we need to invalidate
> once for each affected exec_queue.
>
> Fixes: 5387e865d90e ("drm/xe: Add TLB invalidation fence after rebinds issued from execs")
> Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v6.8+
> Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/xe/xe_exec_queue_types.h | 2 ++
> drivers/gpu/drm/xe/xe_pt.c | 5 +++--
> drivers/gpu/drm/xe/xe_ring_ops.c | 11 ++++-------
> drivers/gpu/drm/xe/xe_sched_job.c | 11 +++++++++++
> drivers/gpu/drm/xe/xe_sched_job_types.h | 2 ++
> drivers/gpu/drm/xe/xe_vm_types.h | 5 +++++
> 6 files changed, 27 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue_types.h b/drivers/gpu/drm/xe/xe_exec_queue_types.h
> index 62b3d9d1d7cd..891ad30e906f 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue_types.h
> +++ b/drivers/gpu/drm/xe/xe_exec_queue_types.h
> @@ -148,6 +148,8 @@ struct xe_exec_queue {
> const struct xe_ring_ops *ring_ops;
> /** @entity: DRM sched entity for this exec queue (1 to 1 relationship) */
> struct drm_sched_entity *entity;
> + /** @tlb_flush_seqno: The seqno of the last rebind tlb flush performed */
> + u64 tlb_flush_seqno;
> /** @lrc: logical ring context for this exec queue */
> struct xe_lrc lrc[];
> };
> diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
> index 8d3922d2206e..21bc0d13fccf 100644
> --- a/drivers/gpu/drm/xe/xe_pt.c
> +++ b/drivers/gpu/drm/xe/xe_pt.c
> @@ -1254,11 +1254,12 @@ __xe_pt_bind_vma(struct xe_tile *tile, struct xe_vma *vma, struct xe_exec_queue
> * non-faulting LR, in particular on user-space batch buffer chaining,
> * it needs to be done here.
> */
> - if ((rebind && !xe_vm_in_lr_mode(vm) && !vm->batch_invalidate_tlb) ||
> - (!rebind && xe_vm_has_scratch(vm) && xe_vm_in_preempt_fence_mode(vm))) {
> + if ((!rebind && xe_vm_has_scratch(vm) && xe_vm_in_preempt_fence_mode(vm))) {
Looked why this works in fault mode, we disallow scratch page in fault
mode. I thought at one point we had implementation for that [1] but it
looks like it never got merged. Some to keep an eye on.
[1] https://patchwork.freedesktop.org/series/120480/
> ifence = kzalloc(sizeof(*ifence), GFP_KERNEL);
> if (!ifence)
> return ERR_PTR(-ENOMEM);
> + } else if (rebind && !xe_vm_in_lr_mode(vm) && !vm->batch_invalidate_tlb) {
> + vm->tlb_flush_seqno++;
Can we unwind this if / else clause a bit?
I think batch_invalidate_tlb can only be true if !xe_vm_in_lr_mode(vm).
So else if 'rebind && !xe_vm_in_lr_mode(vm)' should work. Also if
batch_invalidate_tlb is we true we always issue TLB invalidate anyways
and incrementing the seqno is harmles too.
Side note, I'd be remiss if I didn't mention that I really do not like
updating these functions (__xe_pt_bind_vma / __xe_pt_unbind_vma) as they
are going away / being reworked here [2] in order to implement 1 job per
IOCTL / proper error handling.
[2] https://patchwork.freedesktop.org/series/125608/
> }
>
> rfence = kzalloc(sizeof(*rfence), GFP_KERNEL);
> diff --git a/drivers/gpu/drm/xe/xe_ring_ops.c b/drivers/gpu/drm/xe/xe_ring_ops.c
> index c4edffcd4a32..5b2b37b59813 100644
> --- a/drivers/gpu/drm/xe/xe_ring_ops.c
> +++ b/drivers/gpu/drm/xe/xe_ring_ops.c
> @@ -219,10 +219,9 @@ static void __emit_job_gen12_simple(struct xe_sched_job *job, struct xe_lrc *lrc
> {
> u32 dw[MAX_JOB_SIZE_DW], i = 0;
> u32 ppgtt_flag = get_ppgtt_flag(job);
> - struct xe_vm *vm = job->q->vm;
> struct xe_gt *gt = job->q->gt;
>
> - if (vm && vm->batch_invalidate_tlb) {
> + if (job->ring_ops_flush_tlb) {
> dw[i++] = preparser_disable(true);
> i = emit_flush_imm_ggtt(xe_lrc_start_seqno_ggtt_addr(lrc),
> seqno, true, dw, i);
> @@ -270,7 +269,6 @@ static void __emit_job_gen12_video(struct xe_sched_job *job, struct xe_lrc *lrc,
> struct xe_gt *gt = job->q->gt;
> struct xe_device *xe = gt_to_xe(gt);
> bool decode = job->q->class == XE_ENGINE_CLASS_VIDEO_DECODE;
> - struct xe_vm *vm = job->q->vm;
>
> dw[i++] = preparser_disable(true);
>
> @@ -282,13 +280,13 @@ static void __emit_job_gen12_video(struct xe_sched_job *job, struct xe_lrc *lrc,
> i = emit_aux_table_inv(gt, VE0_AUX_INV, dw, i);
> }
>
> - if (vm && vm->batch_invalidate_tlb)
> + if (job->ring_ops_flush_tlb)
> i = emit_flush_imm_ggtt(xe_lrc_start_seqno_ggtt_addr(lrc),
> seqno, true, dw, i);
>
> dw[i++] = preparser_disable(false);
>
> - if (!vm || !vm->batch_invalidate_tlb)
> + if (!job->ring_ops_flush_tlb)
> i = emit_store_imm_ggtt(xe_lrc_start_seqno_ggtt_addr(lrc),
> seqno, dw, i);
>
> @@ -317,7 +315,6 @@ static void __emit_job_gen12_render_compute(struct xe_sched_job *job,
> struct xe_gt *gt = job->q->gt;
> struct xe_device *xe = gt_to_xe(gt);
> bool lacks_render = !(gt->info.engine_mask & XE_HW_ENGINE_RCS_MASK);
> - struct xe_vm *vm = job->q->vm;
> u32 mask_flags = 0;
>
> dw[i++] = preparser_disable(true);
> @@ -327,7 +324,7 @@ static void __emit_job_gen12_render_compute(struct xe_sched_job *job,
> mask_flags = PIPE_CONTROL_3D_ENGINE_FLAGS;
>
> /* See __xe_pt_bind_vma() for a discussion on TLB invalidations. */
> - i = emit_pipe_invalidate(mask_flags, vm && vm->batch_invalidate_tlb, dw, i);
> + i = emit_pipe_invalidate(mask_flags, job->ring_ops_flush_tlb, dw, i);
>
> /* hsdes: 1809175790 */
> if (has_aux_ccs(xe))
> diff --git a/drivers/gpu/drm/xe/xe_sched_job.c b/drivers/gpu/drm/xe/xe_sched_job.c
> index 8151ddafb940..d55458d915a9 100644
> --- a/drivers/gpu/drm/xe/xe_sched_job.c
> +++ b/drivers/gpu/drm/xe/xe_sched_job.c
> @@ -250,6 +250,17 @@ bool xe_sched_job_completed(struct xe_sched_job *job)
>
> void xe_sched_job_arm(struct xe_sched_job *job)
> {
> + struct xe_exec_queue *q = job->q;
> + struct xe_vm *vm = q->vm;
> +
> + if (vm && !xe_sched_job_is_migration(q) && !xe_vm_in_lr_mode(vm) &&
> + vm->tlb_flush_seqno != q->tlb_flush_seqno) {
> + q->tlb_flush_seqno = vm->tlb_flush_seqno;
> + job->ring_ops_flush_tlb = true;
> + } else if (vm && vm->batch_invalidate_tlb) {
> + job->ring_ops_flush_tlb = true;
> + }
> +
Can we simplify this too?
if (vm && (vm->batch_invalidate_tlb || (vm->tlb_flush_seqno != q->tlb_flush_seqno))) {
q->tlb_flush_seqno = vm->tlb_flush_seqno;
job->ring_ops_flush_tlb = true;
}
I think this works as xe_sched_job_is_migration has
emit_migration_job_gen12 which doesn't look at job->ring_ops_flush_tlb,
so no need to xe_sched_job_is_migration.
Also no need to check xe_vm_in_lr_mode as we wouldn'y increment the
seqno above if that true.
Lastly, harmless to increment q->tlb_flush_seqno in the case of
batch_invalidate_tlb being true.
> drm_sched_job_arm(&job->drm);
> }
>
> diff --git a/drivers/gpu/drm/xe/xe_sched_job_types.h b/drivers/gpu/drm/xe/xe_sched_job_types.h
> index b1d83da50a53..5e12724219fd 100644
> --- a/drivers/gpu/drm/xe/xe_sched_job_types.h
> +++ b/drivers/gpu/drm/xe/xe_sched_job_types.h
> @@ -39,6 +39,8 @@ struct xe_sched_job {
> } user_fence;
> /** @migrate_flush_flags: Additional flush flags for migration jobs */
> u32 migrate_flush_flags;
> + /** @ring_ops_flush_tlb: The ring ops need to flush TLB before payload. */
> + bool ring_ops_flush_tlb;
How about JOB_FLAG_FLUSH_TLB rather than a new field? See
JOB_FLAG_SUBMIT flag usage.
Matt
> /** @batch_addr: batch buffer address of job */
> u64 batch_addr[];
> };
> diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
> index ae5fb565f6bf..5747f136d24d 100644
> --- a/drivers/gpu/drm/xe/xe_vm_types.h
> +++ b/drivers/gpu/drm/xe/xe_vm_types.h
> @@ -264,6 +264,11 @@ struct xe_vm {
> bool capture_once;
> } error_capture;
>
> + /**
> + * @tlb_flush_seqno: Required TLB flush seqno for the next exec.
> + * protected by the vm resv.
> + */
> + u64 tlb_flush_seqno;
> /** @batch_invalidate_tlb: Always invalidate TLB before batch start */
> bool batch_invalidate_tlb;
> /** @xef: XE file handle for tracking this VM's drm client */
> --
> 2.44.0
>
