From mboxrd@z Thu Jan 1 00:00:00 1970 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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 9D6A4C07E96 for ; Tue, 6 Jul 2021 18:27:59 +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 54F4261C54 for ; Tue, 6 Jul 2021 18:27:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54F4261C54 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 CDEC56E580; Tue, 6 Jul 2021 18:27:58 +0000 (UTC) Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTPS id 940F56E580; Tue, 6 Jul 2021 18:27:57 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10037"; a="206161450" X-IronPort-AV: E=Sophos;i="5.83,329,1616482800"; d="scan'208";a="206161450" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jul 2021 11:27:56 -0700 X-IronPort-AV: E=Sophos;i="5.83,329,1616482800"; d="scan'208";a="457167097" Received: from johnharr-mobl1.amr.corp.intel.com (HELO [10.212.151.177]) ([10.212.151.177]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jul 2021 11:27:56 -0700 To: Matthew Brost , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org References: <20210701171550.49353-1-matthew.brost@intel.com> <20210701171550.49353-6-matthew.brost@intel.com> From: John Harrison Message-ID: <6d1007b2-1f84-80e5-a598-81c7e0f4727d@intel.com> Date: Tue, 6 Jul 2021 11:27:55 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210701171550.49353-6-matthew.brost@intel.com> Content-Language: en-GB Subject: Re: [Intel-gfx] [PATCH 5/7] 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: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 7/1/2021 10:15, Matthew Brost wrote: > Implement a stall timer which fails H2G CTBs once a period of time > with no forward progress is reached to prevent deadlock. > > v2: > (Michal) > - Improve error message in ct_deadlock() > - Set broken when ct_deadlock() returns true > - Return -EPIPE on ct_deadlock() > v3: > (Michal) > - Add ms to stall timer comment > (Matthew) > - Move broken check to intel_guc_ct_send() > > Signed-off-by: John Harrison > Signed-off-by: Daniele Ceraolo Spurio > Signed-off-by: Matthew Brost Looks plausible to me. Reviewed-by: John Harrison > --- > drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 62 ++++++++++++++++++++--- > drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h | 4 ++ > 2 files changed, 59 insertions(+), 7 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 fb825cc1d090..a9cb7b608520 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c > @@ -4,6 +4,9 @@ > */ > > #include > +#include > +#include > +#include > > #include "i915_drv.h" > #include "intel_guc_ct.h" > @@ -316,6 +319,7 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct) > goto err_deregister; > > ct->enabled = true; > + ct->stall_time = KTIME_MAX; > > return 0; > > @@ -388,9 +392,6 @@ static int ct_write(struct intel_guc_ct *ct, > u32 *cmds = ctb->cmds; > unsigned int i; > > - if (unlikely(ctb->broken)) > - return -EPIPE; > - > if (unlikely(desc->status)) > goto corrupted; > > @@ -506,6 +507,25 @@ static int wait_for_ct_request_update(struct ct_request *req, u32 *status) > return err; > } > > +#define GUC_CTB_TIMEOUT_MS 1500 > +static inline bool ct_deadlocked(struct intel_guc_ct *ct) > +{ > + long timeout = GUC_CTB_TIMEOUT_MS; > + bool ret = ktime_ms_delta(ktime_get(), ct->stall_time) > timeout; > + > + if (unlikely(ret)) { > + struct guc_ct_buffer_desc *send = ct->ctbs.send.desc; > + struct guc_ct_buffer_desc *recv = ct->ctbs.send.desc; > + > + CT_ERROR(ct, "Communication stalled for %lld ms, desc status=%#x,%#x\n", > + ktime_ms_delta(ktime_get(), ct->stall_time), > + send->status, recv->status); > + ct->ctbs.send.broken = true; > + } > + > + return ret; > +} > + > static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) > { > struct guc_ct_buffer_desc *desc = ctb->desc; > @@ -517,6 +537,26 @@ static inline bool h2g_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(!h2g_has_room(ctb, len_dw))) { > + if (ct->stall_time == KTIME_MAX) > + ct->stall_time = ktime_get(); > + > + if (unlikely(ct_deadlocked(ct))) > + return -EPIPE; > + 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, > @@ -529,11 +569,9 @@ static int ct_send_nb(struct intel_guc_ct *ct, > > spin_lock_irqsave(&ctb->lock, spin_flags); > > - ret = h2g_has_room(ctb, len + GUC_CTB_HDR_LEN); > - if (unlikely(!ret)) { > - ret = -EBUSY; > + ret = has_room_nb(ct, len + GUC_CTB_HDR_LEN); > + if (unlikely(ret)) > goto out; > - } > > fence = ct_get_next_fence(ct); > ret = ct_write(ct, action, len, fence, flags); > @@ -576,8 +614,13 @@ static int ct_send(struct intel_guc_ct *ct, > retry: > spin_lock_irqsave(&ctb->lock, flags); > if (unlikely(!h2g_has_room(ctb, len + GUC_CTB_HDR_LEN))) { > + if (ct->stall_time == KTIME_MAX) > + ct->stall_time = ktime_get(); > spin_unlock_irqrestore(&ctb->lock, flags); > > + if (unlikely(ct_deadlocked(ct))) > + return -EPIPE; > + > if (msleep_interruptible(sleep_period_ms)) > return -EINTR; > sleep_period_ms = sleep_period_ms << 1; > @@ -585,6 +628,8 @@ static int ct_send(struct intel_guc_ct *ct, > goto retry; > } > > + ct->stall_time = KTIME_MAX; > + > fence = ct_get_next_fence(ct); > request.fence = fence; > request.status = 0; > @@ -647,6 +692,9 @@ int intel_guc_ct_send(struct intel_guc_ct *ct, const u32 *action, u32 len, > return -ENODEV; > } > > + if (unlikely(ct->ctbs.send.broken)) > + return -EPIPE; > + > if (flags & INTEL_GUC_CT_SEND_NB) > return ct_send_nb(ct, action, len, flags); > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > index 5bb8bef024c8..bee03794c1eb 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > > #include "intel_guc_fwif.h" > > @@ -68,6 +69,9 @@ struct intel_guc_ct { > struct list_head incoming; /* incoming requests */ > struct work_struct worker; /* handler for incoming requests */ > } requests; > + > + /** @stall_time: time of first time a CTB submission is stalled */ > + ktime_t stall_time; > }; > > void intel_guc_ct_init_early(struct intel_guc_ct *ct); _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx