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 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 C7B94C433EF for ; Wed, 20 Jul 2022 10:17:22 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E73D611A831; Wed, 20 Jul 2022 10:17:20 +0000 (UTC) Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by gabe.freedesktop.org (Postfix) with ESMTPS id 982B311A831; Wed, 20 Jul 2022 10:17:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1658312239; x=1689848239; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=kbIA9F2nesf8cCzHMeeWiZJ3SXBcx+oFl6bHtEenIGE=; b=P3LSwuF7n1LCcCqertIGfhrD6dTEkiyazcj9wIsmuwZ0zrxb0QhyOks1 /xLvd0hubCIovSeB7VDJqoozCjKKqMU0Bjo4hd1RCz7oKnd5uk/ySp8r6 8kHLL1spQafGQG/dGUf3AJ6frCYIV1rWRfzjJu+sxOfJyjWpJOGo0rmSm 4GPWNROlBaec9HNU5UJjcorVNrvvndfhSm+jXl8j1y6Zr82Lc0WlaGqOr Wz6DfqrA8QlECqDhY2x8LhjSMq0EM0DOn+PVc1jaJirjp8VkPs2cTxBJ0 TLTsOqgNLzo/TOxIL1wYOZVqIZOOgaGWdriQHo9O1s/ji0pig7ertWBTH g==; X-IronPort-AV: E=McAfee;i="6400,9594,10413"; a="269764425" X-IronPort-AV: E=Sophos;i="5.92,286,1650956400"; d="scan'208";a="269764425" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jul 2022 03:17:19 -0700 X-IronPort-AV: E=Sophos;i="5.92,286,1650956400"; d="scan'208";a="625604475" Received: from jkrzyszt-mobl1.ger.corp.intel.com ([10.213.21.190]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jul 2022 03:17:14 -0700 From: Janusz Krzysztofik To: intel-gfx@lists.freedesktop.org Subject: [PATCH 1/2] drm/i915/gem: Avoid taking runtime-pm under the shrinker Date: Wed, 20 Jul 2022 12:16:51 +0200 Message-Id: <20220720101652.93293-1-janusz.krzysztofik@linux.intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Tvrtko Ursulin , dri-devel@lists.freedesktop.org, Chris Wilson , Matthew Auld , Janusz Krzysztofik Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Chris Wilson Inside the shrinker, we cannot wake the device as that may cause recursion into fs-reclaim, so instead we only unbind vma if the device is currently awake. (In order to provide reclaim while asleep, we do wake the device up during kswapd -- we probably want to limit that wake up if we have anything to shrink though!) To avoid the same fs_reclaim recursion potential during i915_gem_object_unbind, we acquire a wakeref there, see commit 3e817471a34c ("drm/i915/gem: Take runtime-pm wakeref prior to unbinding"). However, we use i915_gem_object_unbind from the shrinker path to make the object available for shrinking and so we must make the wakeref acquisition here conditional. <4> [437.542172] ====================================================== <4> [437.542174] WARNING: possible circular locking dependency detected <4> [437.542176] 5.19.0-rc6-CI_DRM_11876-g2305e0d00665+ #1 Tainted: G U <4> [437.542179] ------------------------------------------------------ <4> [437.542181] kswapd0/93 is trying to acquire lock: <4> [437.542183] ffffffff827a7608 (acpi_wakeup_lock){+.+.}-{3:3}, at: acpi_device_wakeup_disable+0x12/0x50 <4> [437.542191] but task is already holding lock: <4> [437.542194] ffffffff8275d360 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x91/0x5c0 <4> [437.542199] which lock already depends on the new lock. <4> [437.542202] the existing dependency chain (in reverse order) is: <4> [437.542204] -> #2 (fs_reclaim){+.+.}-{0:0}: <4> [437.542207] fs_reclaim_acquire+0x9d/0xd0 <4> [437.542211] kmem_cache_alloc_trace+0x2a/0x250 <4> [437.542214] __acpi_device_add+0x263/0x3a0 <4> [437.542217] acpi_add_single_object+0x3ea/0x710 <4> [437.542220] acpi_bus_check_add+0xf7/0x240 <4> [437.542222] acpi_bus_scan+0x34/0xf0 <4> [437.542224] acpi_scan_init+0xf5/0x241 <4> [437.542228] acpi_init+0x449/0x4aa <4> [437.542230] do_one_initcall+0x53/0x2e0 <4> [437.542233] kernel_init_freeable+0x18f/0x1dd <4> [437.542236] kernel_init+0x11/0x110 <4> [437.542239] ret_from_fork+0x1f/0x30 <4> [437.542241] -> #1 (acpi_device_lock){+.+.}-{3:3}: <4> [437.542245] __mutex_lock+0x97/0xf20 <4> [437.542246] acpi_enable_wakeup_device_power+0x30/0xf0 <4> [437.542249] __acpi_device_wakeup_enable+0x31/0x110 <4> [437.542252] acpi_pm_set_device_wakeup+0x55/0x100 <4> [437.542254] __pci_enable_wake+0x5e/0xa0 <4> [437.542257] pci_finish_runtime_suspend+0x32/0x70 <4> [437.542259] pci_pm_runtime_suspend+0xa3/0x160 <4> [437.542262] __rpm_callback+0x3d/0x110 <4> [437.542265] rpm_callback+0x54/0x60 <4> [437.542268] rpm_suspend.part.10+0x105/0x5a0 <4> [437.542270] pm_runtime_work+0x7d/0x1e0 <4> [437.542273] process_one_work+0x272/0x5c0 <4> [437.542276] worker_thread+0x37/0x370 <4> [437.542278] kthread+0xed/0x120 <4> [437.542280] ret_from_fork+0x1f/0x30 <4> [437.542282] -> #0 (acpi_wakeup_lock){+.+.}-{3:3}: <4> [437.542285] __lock_acquire+0x15ad/0x2940 <4> [437.542288] lock_acquire+0xd3/0x310 <4> [437.542291] __mutex_lock+0x97/0xf20 <4> [437.542293] acpi_device_wakeup_disable+0x12/0x50 <4> [437.542295] acpi_pm_set_device_wakeup+0x6e/0x100 <4> [437.542297] __pci_enable_wake+0x73/0xa0 <4> [437.542300] pci_pm_runtime_resume+0x45/0x90 <4> [437.542302] __rpm_callback+0x3d/0x110 <4> [437.542304] rpm_callback+0x54/0x60 <4> [437.542307] rpm_resume+0x54f/0x750 <4> [437.542309] __pm_runtime_resume+0x42/0x80 <4> [437.542311] __intel_runtime_pm_get+0x19/0x80 [i915] <4> [437.542386] i915_gem_object_unbind+0x8f/0x3b0 [i915] <4> [437.542487] i915_gem_shrink+0x634/0x850 [i915] <4> [437.542584] i915_gem_shrinker_scan+0x3a/0xc0 [i915] <4> [437.542679] shrink_slab.constprop.97+0x1a4/0x4f0 <4> [437.542684] shrink_node+0x21e/0x420 <4> [437.542687] balance_pgdat+0x241/0x5c0 <4> [437.542690] kswapd+0x229/0x4f0 <4> [437.542694] kthread+0xed/0x120 <4> [437.542697] ret_from_fork+0x1f/0x30 <4> [437.542701] other info that might help us debug this: <4> [437.542705] Chain exists of: acpi_wakeup_lock --> acpi_device_lock --> fs_reclaim <4> [437.542713] Possible unsafe locking scenario: <4> [437.542716] CPU0 CPU1 <4> [437.542719] ---- ---- <4> [437.542721] lock(fs_reclaim); <4> [437.542725] lock(acpi_device_lock); <4> [437.542728] lock(fs_reclaim); <4> [437.542732] lock(acpi_wakeup_lock); <4> [437.542736] *** DEADLOCK *** Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/6449 Fixes: 3e817471a34c ("drm/i915/gem: Take runtime-pm wakeref prior to unbinding") Signed-off-by: Chris Wilson Cc: Matthew Auld Cc: # v5.6+ Signed-off-by: Janusz Krzysztofik --- drivers/gpu/drm/i915/i915_gem.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 702e5b89be22..910a6fde5726 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -119,8 +119,8 @@ int i915_gem_object_unbind(struct drm_i915_gem_object *obj, { struct intel_runtime_pm *rpm = &to_i915(obj->base.dev)->runtime_pm; bool vm_trylock = !!(flags & I915_GEM_OBJECT_UNBIND_VM_TRYLOCK); + intel_wakeref_t wakeref = 0; LIST_HEAD(still_in_list); - intel_wakeref_t wakeref; struct i915_vma *vma; int ret; @@ -135,7 +135,8 @@ int i915_gem_object_unbind(struct drm_i915_gem_object *obj, * as they are required by the shrinker. Ergo, we wake the device up * first just in case. */ - wakeref = intel_runtime_pm_get(rpm); + if (!(flags & I915_GEM_OBJECT_UNBIND_TEST)) + wakeref = intel_runtime_pm_get(rpm); try_again: ret = 0; @@ -200,7 +201,8 @@ int i915_gem_object_unbind(struct drm_i915_gem_object *obj, goto try_again; } - intel_runtime_pm_put(rpm, wakeref); + if (wakeref) + intel_runtime_pm_put(rpm, wakeref); return ret; } -- 2.25.1