From patchwork Thu Nov 30 00:20:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Previn X-Patchwork-Id: 13473693 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B576CC4167B for ; Thu, 30 Nov 2023 00:20:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B9C8010E69B; Thu, 30 Nov 2023 00:20:26 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1E56110E69B; Thu, 30 Nov 2023 00:20:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701303625; x=1732839625; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=o82GL61sMcpg8Mp6hDi9PDPoJiKJ+r1YJKZQkIvEAuU=; b=EmyRX90SxgwlDJtzXlbV4e+FKR9wIQpuWfwYR4Iv9pBEC7oXgYx7fQp9 BRwCijdPbbwDWay+0ESr32iWB4XDeIBmFqLWXYxOuPNCbYemd8miz2I2H k0hYUrXMBjT50FHuvo01k/upF5CkVUxScft244PxxY0mCikVotVQHEwpY xI/Pgq/YVxRNf2mhn9j2199OxnFvGw57QkyLfk7crJ/8TGmKJL3f/ZC5P E6sUNWW8e380KLnPGacmEt29nOFFtD6B3uJMFYe/HInT9/fJNv73q7KGO QrkWNmL3hFzZ+PlfYH5o78csJ5whe6MXNKi+mnO3/EDT7UthnMqevqmQ4 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10909"; a="373429290" X-IronPort-AV: E=Sophos;i="6.04,237,1695711600"; d="scan'208";a="373429290" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Nov 2023 16:20:16 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10909"; a="798099358" X-IronPort-AV: E=Sophos;i="6.04,237,1695711600"; d="scan'208";a="798099358" Received: from aalteres-desk.fm.intel.com ([10.80.57.53]) by orsmga008.jf.intel.com with ESMTP; 29 Nov 2023 16:20:16 -0800 From: Alan Previn To: intel-gfx@lists.freedesktop.org Subject: [PATCH v7 1/2] drm/i915/guc: Flush context destruction worker at suspend Date: Wed, 29 Nov 2023 16:20:12 -0800 Message-Id: <20231130002013.282804-2-alan.previn.teres.alexis@intel.com> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20231130002013.282804-1-alan.previn.teres.alexis@intel.com> References: <20231130002013.282804-1-alan.previn.teres.alexis@intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alan Previn , Tvrtko Ursulin , Anshuman Gupta , dri-devel@lists.freedesktop.org, Daniele Ceraolo Spurio , Rodrigo Vivi , Mousumi Jana , John Harrison Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" When suspending, flush the context-guc-id deregistration worker at the final stages of intel_gt_suspend_late when we finally call gt_sanitize that eventually leads down to __uc_sanitize so that the deregistration worker doesn't fire off later as we reset the GuC microcontroller. Signed-off-by: Alan Previn Reviewed-by: Rodrigo Vivi Tested-by: Mousumi Jana --- drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 5 +++++ drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h | 2 ++ drivers/gpu/drm/i915/gt/uc/intel_uc.c | 2 ++ 3 files changed, 9 insertions(+) diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index 04f8377fd7a3..6e3fb2fcce4f 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -1613,6 +1613,11 @@ static void guc_flush_submissions(struct intel_guc *guc) spin_unlock_irqrestore(&sched_engine->lock, flags); } +void intel_guc_submission_flush_work(struct intel_guc *guc) +{ + flush_work(&guc->submission_state.destroyed_worker); +} + static void guc_flush_destroyed_contexts(struct intel_guc *guc); void intel_guc_submission_reset_prepare(struct intel_guc *guc) diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h index c57b29cdb1a6..b6df75622d3b 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h @@ -38,6 +38,8 @@ int intel_guc_wait_for_pending_msg(struct intel_guc *guc, bool interruptible, long timeout); +void intel_guc_submission_flush_work(struct intel_guc *guc); + static inline bool intel_guc_submission_is_supported(struct intel_guc *guc) { return guc->submission_supported; diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c index 3872d309ed31..b8b09b1bee3e 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c @@ -690,6 +690,8 @@ void intel_uc_suspend(struct intel_uc *uc) return; } + intel_guc_submission_flush_work(guc); + with_intel_runtime_pm(&uc_to_gt(uc)->i915->runtime_pm, wakeref) { err = intel_guc_suspend(guc); if (err) From patchwork Thu Nov 30 00:20:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Previn X-Patchwork-Id: 13473694 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 29354C10DC2 for ; Thu, 30 Nov 2023 00:20:40 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8FC2E10E6A2; Thu, 30 Nov 2023 00:20:28 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by gabe.freedesktop.org (Postfix) with ESMTPS id 48E2C10E69E; Thu, 30 Nov 2023 00:20:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701303625; x=1732839625; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=V0qfuaOHccul1W4euNNreKr/J4/h0fbnkot/ShEYMNg=; b=WRVCVWWm3XvtfqmJ5vA+oQrfuPDcbp0n2v1TzPvixI2RjZl5Gk+DF4U8 Gsttwp+Wi2AuMbAsgF5YfCFIf7o26lRYJ84/TmoTNRuCjA9dGR2Q2n29W QaIA93ZchzEMtU0XxaeIdPfXDBLQIBTiWsGk/4/I+6+YD+O+LIZ8Br905 QLtEbROMYQ+GQJAckYrztVAbVS4I5ycnhSNiVS/wK88VQXBfphnCACSTd rOTgEBQOJYP2M0X1AX24gt+teFQT9FLSBnk9vxk7l0R1wX+QC4fni2BXP uWZIS8i5dFaxFcled/ZS2i3NleWMlCQH7YerqQCW89c53WQTdlERE5zz1 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10909"; a="373429291" X-IronPort-AV: E=Sophos;i="6.04,237,1695711600"; d="scan'208";a="373429291" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Nov 2023 16:20:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10909"; a="798099361" X-IronPort-AV: E=Sophos;i="6.04,237,1695711600"; d="scan'208";a="798099361" Received: from aalteres-desk.fm.intel.com ([10.80.57.53]) by orsmga008.jf.intel.com with ESMTP; 29 Nov 2023 16:20:16 -0800 From: Alan Previn To: intel-gfx@lists.freedesktop.org Subject: [PATCH v7 2/2] drm/i915/guc: Close deregister-context race against CT-loss Date: Wed, 29 Nov 2023 16:20:13 -0800 Message-Id: <20231130002013.282804-3-alan.previn.teres.alexis@intel.com> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20231130002013.282804-1-alan.previn.teres.alexis@intel.com> References: <20231130002013.282804-1-alan.previn.teres.alexis@intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alan Previn , Tvrtko Ursulin , Anshuman Gupta , dri-devel@lists.freedesktop.org, Daniele Ceraolo Spurio , Rodrigo Vivi , Mousumi Jana , John Harrison Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" If we are at the end of suspend or very early in resume its possible an async fence signal (via rcu_call) is triggered to free_engines which could lead us to the execution of the context destruction worker (after a prior worker flush). Thus, when suspending, insert rcu_barriers at the start of i915_gem_suspend (part of driver's suspend prepare) and again in i915_gem_suspend_late so that all such cases have completed and context destruction list isn't missing anything. In destroyed_worker_func, close the race against CT-loss by checking that CT is enabled before calling into deregister_destroyed_contexts. Based on testing, guc_lrc_desc_unpin may still race and fail as we traverse the GuC's context-destroy list because the CT could be disabled right before calling GuC's CT send function. We've witnessed this race condition once every ~6000-8000 suspend-resume cycles while ensuring workloads that render something onscreen is continuously started just before we suspend (and the workload is small enough to complete and trigger the queued engine/context free-up either very late in suspend or very early in resume). In such a case, we need to unroll the entire process because guc-lrc-unpin takes a gt wakeref which only gets released in the G2H IRQ reply that never comes through in this corner case. Without the unroll, the taken wakeref is leaked and will cascade into a kernel hang later at the tail end of suspend in this function: intel_wakeref_wait_for_idle(>->wakeref) (called by) - intel_gt_pm_wait_for_idle (called by) - wait_for_suspend Thus, do an unroll in guc_lrc_desc_unpin and deregister_destroyed_- contexts if guc_lrc_desc_unpin fails due to CT send falure. When unrolling, keep the context in the GuC's destroy-list so it can get picked up on the next destroy worker invocation (if suspend aborted) or get fully purged as part of a GuC sanitization (end of suspend) or a reset flow. Signed-off-by: Alan Previn Signed-off-by: Anshuman Gupta Tested-by: Mousumi Jana Acked-by: Daniele Ceraolo Spurio --- drivers/gpu/drm/i915/gem/i915_gem_pm.c | 10 +++ .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 73 +++++++++++++++++-- 2 files changed, 78 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_pm.c index 0d812f4d787d..3b27218aabe2 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_pm.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_pm.c @@ -28,6 +28,13 @@ void i915_gem_suspend(struct drm_i915_private *i915) GEM_TRACE("%s\n", dev_name(i915->drm.dev)); intel_wakeref_auto(&i915->runtime_pm.userfault_wakeref, 0); + /* + * On rare occasions, we've observed the fence completion triggers + * free_engines asynchronously via rcu_call. Ensure those are done. + * This path is only called on suspend, so it's an acceptable cost. + */ + rcu_barrier(); + flush_workqueue(i915->wq); /* @@ -160,6 +167,9 @@ void i915_gem_suspend_late(struct drm_i915_private *i915) * machine in an unusable condition. */ + /* Like i915_gem_suspend, flush tasks staged from fence triggers */ + rcu_barrier(); + for_each_gt(gt, i915, i) intel_gt_suspend_late(gt); diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index 6e3fb2fcce4f..a7228bebec39 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -236,6 +236,13 @@ set_context_destroyed(struct intel_context *ce) ce->guc_state.sched_state |= SCHED_STATE_DESTROYED; } +static inline void +clr_context_destroyed(struct intel_context *ce) +{ + lockdep_assert_held(&ce->guc_state.lock); + ce->guc_state.sched_state &= ~SCHED_STATE_DESTROYED; +} + static inline bool context_pending_disable(struct intel_context *ce) { return ce->guc_state.sched_state & SCHED_STATE_PENDING_DISABLE; @@ -613,6 +620,8 @@ static int guc_submission_send_busy_loop(struct intel_guc *guc, u32 g2h_len_dw, bool loop) { + int ret; + /* * We always loop when a send requires a reply (i.e. g2h_len_dw > 0), * so we don't handle the case where we don't get a reply because we @@ -623,7 +632,11 @@ static int guc_submission_send_busy_loop(struct intel_guc *guc, if (g2h_len_dw) atomic_inc(&guc->outstanding_submission_g2h); - return intel_guc_send_busy_loop(guc, action, len, g2h_len_dw, loop); + ret = intel_guc_send_busy_loop(guc, action, len, g2h_len_dw, loop); + if (ret) + atomic_dec(&guc->outstanding_submission_g2h); + + return ret; } int intel_guc_wait_for_pending_msg(struct intel_guc *guc, @@ -3288,12 +3301,13 @@ static void guc_context_close(struct intel_context *ce) spin_unlock_irqrestore(&ce->guc_state.lock, flags); } -static inline void guc_lrc_desc_unpin(struct intel_context *ce) +static inline int guc_lrc_desc_unpin(struct intel_context *ce) { struct intel_guc *guc = ce_to_guc(ce); struct intel_gt *gt = guc_to_gt(guc); unsigned long flags; bool disabled; + int ret; GEM_BUG_ON(!intel_gt_pm_is_awake(gt)); GEM_BUG_ON(!ctx_id_mapped(guc, ce->guc_id.id)); @@ -3304,18 +3318,41 @@ static inline void guc_lrc_desc_unpin(struct intel_context *ce) spin_lock_irqsave(&ce->guc_state.lock, flags); disabled = submission_disabled(guc); if (likely(!disabled)) { + /* + * Take a gt-pm ref and change context state to be destroyed. + * NOTE: a G2H IRQ that comes after will put this gt-pm ref back + */ __intel_gt_pm_get(gt); set_context_destroyed(ce); clr_context_registered(ce); } spin_unlock_irqrestore(&ce->guc_state.lock, flags); + if (unlikely(disabled)) { release_guc_id(guc, ce); __guc_context_destroy(ce); - return; + return 0; } - deregister_context(ce, ce->guc_id.id); + /* + * GuC is active, lets destroy this context, but at this point we can still be racing + * with suspend, so we undo everything if the H2G fails in deregister_context so + * that GuC reset will find this context during clean up. + */ + ret = deregister_context(ce, ce->guc_id.id); + if (ret) { + spin_lock(&ce->guc_state.lock); + set_context_registered(ce); + clr_context_destroyed(ce); + spin_unlock(&ce->guc_state.lock); + /* + * As gt-pm is awake at function entry, intel_wakeref_put_async merely decrements + * the wakeref immediately but per function spec usage call this after unlock. + */ + intel_wakeref_put_async(>->wakeref); + } + + return ret; } static void __guc_context_destroy(struct intel_context *ce) @@ -3383,7 +3420,22 @@ static void deregister_destroyed_contexts(struct intel_guc *guc) if (!ce) break; - guc_lrc_desc_unpin(ce); + if (guc_lrc_desc_unpin(ce)) { + /* + * This means GuC's CT link severed mid-way which could happen + * in suspend-resume corner cases. In this case, put the + * context back into the destroyed_contexts list which will + * get picked up on the next context deregistration event or + * purged in a GuC sanitization event (reset/unload/wedged/...). + */ + spin_lock_irqsave(&guc->submission_state.lock, flags); + list_add_tail(&ce->destroyed_link, + &guc->submission_state.destroyed_contexts); + spin_unlock_irqrestore(&guc->submission_state.lock, flags); + /* Bail now since the list might never be emptied if h2gs fail */ + break; + } + } } @@ -3394,6 +3446,17 @@ static void destroyed_worker_func(struct work_struct *w) struct intel_gt *gt = guc_to_gt(guc); intel_wakeref_t wakeref; + /* + * In rare cases we can get here via async context-free fence-signals that + * come very late in suspend flow or very early in resume flows. In these + * cases, GuC won't be ready but just skipping it here is fine as these + * pending-destroy-contexts get destroyed totally at GuC reset time at the + * end of suspend.. OR.. this worker can be picked up later on the next + * context destruction trigger after resume-completes + */ + if (!intel_guc_is_ready(guc)) + return; + with_intel_gt_pm(gt, wakeref) deregister_destroyed_contexts(guc); }