From patchwork Thu May 6 19:13:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Brost X-Patchwork-Id: 12243289 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57594C433B4 for ; Thu, 6 May 2021 18:59:38 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 0E06E61164 for ; Thu, 6 May 2021 18:59:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0E06E61164 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7B73E6EDD2; Thu, 6 May 2021 18:57:39 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4B7B56ED0B; Thu, 6 May 2021 18:57:13 +0000 (UTC) IronPort-SDR: ekEJtKvkbgk84rooP8Y5wW4msUj+nn7mq1jhDc0gDBxS4xmNWlAdLwNwL3mt8o0YrQeRvUds2h GaaBSzSTf+Og== X-IronPort-AV: E=McAfee;i="6200,9189,9976"; a="198195445" X-IronPort-AV: E=Sophos;i="5.82,278,1613462400"; d="scan'208";a="198195445" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2021 11:57:11 -0700 IronPort-SDR: nCCSCNtGamKfBG8SCymS4JJQnM3mpMWeI092IytNCrzytPUqKg0PCpHNdwQR//0WGlULEzRc4y +DegopQvE4RQ== X-IronPort-AV: E=Sophos;i="5.82,278,1613462400"; d="scan'208";a="469583472" Received: from dhiatt-server.jf.intel.com ([10.54.81.3]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2021 11:57:10 -0700 From: Matthew Brost To: , Date: Thu, 6 May 2021 12:13:51 -0700 Message-Id: <20210506191451.77768-38-matthew.brost@intel.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20210506191451.77768-1-matthew.brost@intel.com> References: <20210506191451.77768-1-matthew.brost@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [RFC PATCH 37/97] drm/i915/guc: Add stall timer to non blocking CTB send function X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jason.ekstrand@intel.com, daniel.vetter@intel.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Implement a stall timer which fails H2G CTBs once a period of time with no forward progress is reached to prevent deadlock. Also update to ct_write to return -EDEADLK rather than -EPIPE on a corrupted descriptor. Signed-off-by: John Harrison Signed-off-by: Daniele Ceraolo Spurio Signed-off-by: Matthew Brost --- drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 48 +++++++++++++++++++++-- 1 file changed, 45 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c index af7314d45a78..4eab319d61be 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c @@ -69,6 +69,8 @@ static inline struct drm_device *ct_to_drm(struct intel_guc_ct *ct) #define CTB_H2G_BUFFER_SIZE (SZ_4K) #define CTB_G2H_BUFFER_SIZE (SZ_4K) +#define MAX_US_STALL_CTB 1000000 + struct ct_request { struct list_head link; u32 fence; @@ -315,6 +317,7 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct) ct->requests.last_fence = 1; ct->enabled = true; + ct->stall_time = KTIME_MAX; return 0; @@ -378,7 +381,7 @@ static int ct_write(struct intel_guc_ct *ct, unsigned int i; if (unlikely(ctb->broken)) - return -EPIPE; + return -EDEADLK; if (unlikely(desc->status)) goto corrupted; @@ -449,7 +452,7 @@ static int ct_write(struct intel_guc_ct *ct, CT_ERROR(ct, "Corrupted descriptor head=%u tail=%u status=%#x\n", desc->head, desc->tail, desc->status); ctb->broken = true; - return -EPIPE; + return -EDEADLK; } /** @@ -494,6 +497,17 @@ static int wait_for_ct_request_update(struct ct_request *req, u32 *status) return err; } +static inline bool ct_deadlocked(struct intel_guc_ct *ct) +{ + bool ret = ktime_us_delta(ktime_get(), ct->stall_time) > + MAX_US_STALL_CTB; + + if (unlikely(ret)) + CT_ERROR(ct, "CT deadlocked\n"); + + return ret; +} + static inline bool ctb_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) { struct guc_ct_buffer_desc *desc = ctb->desc; @@ -505,6 +519,26 @@ static inline bool ctb_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) return space >= len_dw; } +static int has_room_nb(struct intel_guc_ct *ct, u32 len_dw) +{ + struct intel_guc_ct_buffer *ctb = &ct->ctbs.send; + + lockdep_assert_held(&ct->ctbs.send.lock); + + if (unlikely(!ctb_has_room(ctb, len_dw))) { + if (ct->stall_time == KTIME_MAX) + ct->stall_time = ktime_get(); + + if (unlikely(ct_deadlocked(ct))) + return -EDEADLK; + else + return -EBUSY; + } + + ct->stall_time = KTIME_MAX; + return 0; +} + static int ct_send_nb(struct intel_guc_ct *ct, const u32 *action, u32 len, @@ -517,7 +551,7 @@ static int ct_send_nb(struct intel_guc_ct *ct, spin_lock_irqsave(&ctb->lock, spin_flags); - ret = ctb_has_room(ctb, len + 1); + ret = has_room_nb(ct, len + 1); if (unlikely(ret)) goto out; @@ -561,11 +595,19 @@ static int ct_send(struct intel_guc_ct *ct, retry: spin_lock_irqsave(&ct->ctbs.send.lock, flags); if (unlikely(!ctb_has_room(ctb, len + 1))) { + if (ct->stall_time == KTIME_MAX) + ct->stall_time = ktime_get(); spin_unlock_irqrestore(&ct->ctbs.send.lock, flags); + + if (unlikely(ct_deadlocked(ct))) + return -EDEADLK; + cond_resched(); goto retry; } + ct->stall_time = KTIME_MAX; + fence = ct_get_next_fence(ct); request.fence = fence; request.status = 0;