From patchwork Fri Nov 5 15:01:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thomas Hellstrom X-Patchwork-Id: 12604849 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C84B0C433EF for ; Fri, 5 Nov 2021 15:05:34 +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 842B160EBC for ; Fri, 5 Nov 2021 15:05:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 842B160EBC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 15F346EB76; Fri, 5 Nov 2021 15:05:34 +0000 (UTC) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id A810B6EB74 for ; Fri, 5 Nov 2021 15:05:32 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10158"; a="231756607" X-IronPort-AV: E=Sophos;i="5.87,212,1631602800"; d="scan'208";a="231756607" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Nov 2021 08:01:56 -0700 X-IronPort-AV: E=Sophos;i="5.87,212,1631602800"; d="scan'208";a="730548404" Received: from inechita-mobl1.ger.corp.intel.com (HELO thellstr-mobl1.intel.com) ([10.249.254.167]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Nov 2021 08:01:54 -0700 From: =?utf-8?q?Thomas_Hellstr=C3=B6m?= To: intel-gfx@lists.freedesktop.org Date: Fri, 5 Nov 2021 16:01:45 +0100 Message-Id: <20211105150146.834052-1-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v3 1/2] drm/i915/selftests: Use clear_and_wake_up_bit() for the per-engine reset bitlocks 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Some selftests assume that nothing will attempt to grab these bitlocks while they are held by the selftests. With GuC, for example, that is not true because the hanging workloads may cause the GuC code to attempt to grab them for a global reset, and that may cause it to end up sleeping on the bit never waking up. Regardless whether that will be the final solution for GuC, use clear_and_wake_up_bit() pending a more thorough investigation on how this should be handled moving forward. To be clear this needs to be a temporary solution. If we can't find an in-kernel locking primitive to use here, we should at the very least add lockdep annotation to these bitlocks with a thorough explanation as to why we need to use bits. v3: - Use GEM_BUG_ON(test_and_set_bit()) rather than set_bit() to verify the assumption that nothing is holding the reset locks when we attempt to grab them. (Chris Wilson) Signed-off-by: Thomas Hellström Reviewed-by: Matthew Brost --- drivers/gpu/drm/i915/gt/selftest_hangcheck.c | 20 ++++++++++++-------- drivers/gpu/drm/i915/selftests/igt_reset.c | 2 +- 2 files changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c index 7e2d99dd012d..e5ad4d5a91c0 100644 --- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c +++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c @@ -471,7 +471,8 @@ static int igt_reset_nop_engine(void *arg) count = 0; st_engine_heartbeat_disable(engine); - set_bit(I915_RESET_ENGINE + id, >->reset.flags); + GEM_BUG_ON(test_and_set_bit(I915_RESET_ENGINE + id, + >->reset.flags)); do { int i; @@ -528,7 +529,7 @@ static int igt_reset_nop_engine(void *arg) break; } } while (time_before(jiffies, end_time)); - clear_bit(I915_RESET_ENGINE + id, >->reset.flags); + clear_and_wake_up_bit(I915_RESET_ENGINE + id, >->reset.flags); st_engine_heartbeat_enable(engine); pr_info("%s(%s): %d resets\n", __func__, engine->name, count); @@ -582,7 +583,8 @@ static int igt_reset_fail_engine(void *arg) } st_engine_heartbeat_disable(engine); - set_bit(I915_RESET_ENGINE + id, >->reset.flags); + GEM_BUG_ON(test_and_set_bit(I915_RESET_ENGINE + id, + >->reset.flags)); force_reset_timeout(engine); err = intel_engine_reset(engine, NULL); @@ -679,7 +681,7 @@ static int igt_reset_fail_engine(void *arg) out: pr_info("%s(%s): %d resets\n", __func__, engine->name, count); skip: - clear_bit(I915_RESET_ENGINE + id, >->reset.flags); + clear_and_wake_up_bit(I915_RESET_ENGINE + id, >->reset.flags); st_engine_heartbeat_enable(engine); intel_context_put(ce); @@ -734,7 +736,8 @@ static int __igt_reset_engine(struct intel_gt *gt, bool active) reset_engine_count = i915_reset_engine_count(global, engine); st_engine_heartbeat_disable(engine); - set_bit(I915_RESET_ENGINE + id, >->reset.flags); + GEM_BUG_ON(test_and_set_bit(I915_RESET_ENGINE + id, + >->reset.flags)); count = 0; do { struct i915_request *rq = NULL; @@ -824,7 +827,7 @@ static int __igt_reset_engine(struct intel_gt *gt, bool active) if (err) break; } while (time_before(jiffies, end_time)); - clear_bit(I915_RESET_ENGINE + id, >->reset.flags); + clear_and_wake_up_bit(I915_RESET_ENGINE + id, >->reset.flags); st_engine_heartbeat_enable(engine); pr_info("%s: Completed %lu %s resets\n", engine->name, count, active ? "active" : "idle"); @@ -1042,7 +1045,8 @@ static int __igt_reset_engines(struct intel_gt *gt, yield(); /* start all threads before we begin */ st_engine_heartbeat_disable_no_pm(engine); - set_bit(I915_RESET_ENGINE + id, >->reset.flags); + GEM_BUG_ON(test_and_set_bit(I915_RESET_ENGINE + id, + >->reset.flags)); do { struct i915_request *rq = NULL; struct intel_selftest_saved_policy saved; @@ -1165,7 +1169,7 @@ static int __igt_reset_engines(struct intel_gt *gt, if (err) break; } while (time_before(jiffies, end_time)); - clear_bit(I915_RESET_ENGINE + id, >->reset.flags); + clear_and_wake_up_bit(I915_RESET_ENGINE + id, >->reset.flags); st_engine_heartbeat_enable_no_pm(engine); pr_info("i915_reset_engine(%s:%s): %lu resets\n", diff --git a/drivers/gpu/drm/i915/selftests/igt_reset.c b/drivers/gpu/drm/i915/selftests/igt_reset.c index 9f8590b868a9..a2838c65f8a5 100644 --- a/drivers/gpu/drm/i915/selftests/igt_reset.c +++ b/drivers/gpu/drm/i915/selftests/igt_reset.c @@ -36,7 +36,7 @@ void igt_global_reset_unlock(struct intel_gt *gt) enum intel_engine_id id; for_each_engine(engine, gt, id) - clear_bit(I915_RESET_ENGINE + id, >->reset.flags); + clear_and_wake_up_bit(I915_RESET_ENGINE + id, >->reset.flags); clear_bit(I915_RESET_BACKOFF, >->reset.flags); wake_up_all(>->reset.queue);