From 04f4a70a183a688a60fe3882d6e4236ea02cfc67 Mon Sep 17 00:00:00 2001 From: Matthew Brost Date: Mon, 15 Apr 2024 12:04:53 -0700 Subject: [PATCH] drm/xe: Only use reserved BCS instances for usm migrate exec queue The GuC context scheduling queue is 2 entires deep, thus it is possible for a migration job to be stuck behind a fault if migration exec queue shares engines with user jobs. This can deadlock as the migrate exec queue is required to service page faults. Avoid deadlock by only using reserved BCS instances for usm migrate exec queue. Fixes: a043fbab7af5 ("drm/xe/pvc: Use fast copy engines as migrate engine on PVC") Cc: Matt Roper Cc: Niranjana Vishwanathapura Signed-off-by: Matthew Brost Link: https://patchwork.freedesktop.org/patch/msgid/20240415190453.696553-2-matthew.brost@intel.com Reviewed-by: Brian Welty --- drivers/gpu/drm/xe/xe_migrate.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c index 2b12f3621f9e..bacb23de411b 100644 --- a/drivers/gpu/drm/xe/xe_migrate.c +++ b/drivers/gpu/drm/xe/xe_migrate.c @@ -34,7 +34,6 @@ #include "xe_sync.h" #include "xe_trace.h" #include "xe_vm.h" -#include "xe_wa.h" /** * struct xe_migrate - migrate context. @@ -300,10 +299,6 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m, } /* - * Due to workaround 16017236439, odd instance hardware copy engines are - * faster than even instance ones. - * This function returns the mask involving all fast copy engines and the - * reserved copy engine to be used as logical mask for migrate engine. * Including the reserved copy engine is required to avoid deadlocks due to * migrate jobs servicing the faults gets stuck behind the job that faulted. */ @@ -317,8 +312,7 @@ static u32 xe_migrate_usm_logical_mask(struct xe_gt *gt) if (hwe->class != XE_ENGINE_CLASS_COPY) continue; - if (!XE_WA(gt, 16017236439) || - xe_gt_is_usm_hwe(gt, hwe) || hwe->instance & 1) + if (xe_gt_is_usm_hwe(gt, hwe)) logical_mask |= BIT(hwe->logical_instance); } @@ -369,6 +363,10 @@ struct xe_migrate *xe_migrate_init(struct xe_tile *tile) if (!hwe || !logical_mask) return ERR_PTR(-EINVAL); + /* + * XXX: Currently only reserving 1 (likely slow) BCS instance on + * PVC, may want to revisit if performance is needed. + */ m->q = xe_exec_queue_create(xe, vm, logical_mask, 1, hwe, EXEC_QUEUE_FLAG_KERNEL | EXEC_QUEUE_FLAG_PERMANENT | -- 2.25.1