From 155c9165542863c97b5284afa37e3d8e385a8815 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Thomas=20Hellstr=C3=B6m?= Date: Fri, 10 Mar 2023 12:03:47 +0100 Subject: [PATCH] drm/xe: Introduce xe_engine_is_idle() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Introduce xe_engine_is_idle, and replace the static function in xe_migrate.c. The latter had two flaws. First the seqno == 1 test might return a false true value each time the seqno counter wrapped, Second, the cur_seqno == next_seqno test would never return true. Signed-off-by: Thomas Hellström Reviewed-by: Matthew Auld Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/xe/xe_engine.c | 23 +++++++++++++++++++++++ drivers/gpu/drm/xe/xe_engine.h | 2 ++ drivers/gpu/drm/xe/xe_migrate.c | 8 +------- 3 files changed, 26 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_engine.c b/drivers/gpu/drm/xe/xe_engine.c index edd1192f6ec5..8011f5827cbe 100644 --- a/drivers/gpu/drm/xe/xe_engine.c +++ b/drivers/gpu/drm/xe/xe_engine.c @@ -683,6 +683,29 @@ static void engine_kill_compute(struct xe_engine *e) up_write(&e->vm->lock); } +/** + * xe_engine_is_idle() - Whether an engine is idle. + * @engine: The engine + * + * FIXME: Need to determine what to use as the short-lived + * timeline lock for the engines, so that the return value + * of this function becomes more than just an advisory + * snapshot in time. The timeline lock must protect the + * seqno from racing submissions on the same engine. + * Typically vm->resv, but user-created timeline locks use the migrate vm + * and never grabs the migrate vm->resv so we have a race there. + * + * Return: True if the engine is idle, false otherwise. + */ +bool xe_engine_is_idle(struct xe_engine *engine) +{ + if (XE_WARN_ON(xe_engine_is_parallel(engine))) + return false; + + return xe_lrc_seqno(&engine->lrc[0]) == + engine->lrc[0].fence_ctx.next_seqno - 1; +} + void xe_engine_kill(struct xe_engine *e) { struct xe_engine *engine = e, *next; diff --git a/drivers/gpu/drm/xe/xe_engine.h b/drivers/gpu/drm/xe/xe_engine.h index a3a44534003f..1cf7f23c4afd 100644 --- a/drivers/gpu/drm/xe/xe_engine.h +++ b/drivers/gpu/drm/xe/xe_engine.h @@ -42,6 +42,8 @@ static inline bool xe_engine_is_parallel(struct xe_engine *engine) return engine->width > 1; } +bool xe_engine_is_idle(struct xe_engine *engine); + void xe_engine_kill(struct xe_engine *e); int xe_engine_create_ioctl(struct drm_device *dev, void *data, diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c index 366892198d11..4a600c64b5d0 100644 --- a/drivers/gpu/drm/xe/xe_migrate.c +++ b/drivers/gpu/drm/xe/xe_migrate.c @@ -1024,12 +1024,6 @@ static bool no_in_syncs(struct xe_sync_entry *syncs, u32 num_syncs) return true; } -static bool engine_is_idle(struct xe_engine *e) -{ - return !e || e->lrc[0].fence_ctx.next_seqno == 1 || - xe_lrc_seqno(&e->lrc[0]) == e->lrc[0].fence_ctx.next_seqno; -} - /** * xe_migrate_update_pgtables() - Pipelined page-table update * @m: The migrate context. @@ -1082,7 +1076,7 @@ xe_migrate_update_pgtables(struct xe_migrate *m, bool first_munmap_rebind = vma && vma->first_munmap_rebind; /* Use the CPU if no in syncs and engine is idle */ - if (no_in_syncs(syncs, num_syncs) && engine_is_idle(eng)) { + if (no_in_syncs(syncs, num_syncs) && (!eng || xe_engine_is_idle(eng))) { fence = xe_migrate_update_pgtables_cpu(m, vm, bo, updates, num_updates, first_munmap_rebind, -- 2.39.5