From patchwork Tue May 21 07:16:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thomas Hellstrom X-Patchwork-Id: 13668954 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 AFE38C25B78 for ; Tue, 21 May 2024 07:18:06 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 52FDB10E426; Tue, 21 May 2024 07:18:04 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="MAuNj7bM"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.13]) by gabe.freedesktop.org (Postfix) with ESMTPS id CD4C810E36B; Tue, 21 May 2024 07:17:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1716275853; x=1747811853; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=yyCTWfTCAT0eL5il2694dnzuOZVup9F3xSYAIXXUQEI=; b=MAuNj7bMEPCh5zSn4ydwep7bElih6xwJuVQkVApS7DOB7avtMXQHFRmP 73m2OCSwAtOvzb8HAVwqgHh/Qn/Ntb35qDdnkO/o8dNDoCGm+ZH9uprlY THIaYvFgbNtF74Db58BlBVjnTXG6sXwMeeLS/tNo/JZ4LgFZmsQcbARcD Blig2sU/GpOWs6w1rhjDaBvUhNaQ/iPKUiL3zolrGB5qhhOsWB4U2S269 eoIwIjRDV0lYAoHMVeFEA+mZy//qHixbSn6DcQlf/ezTTH6/anFo3i9fj 9fb1e6MqiqImo6+uzlpRbmLRVVSD7l5kuxo5bJQSnrdwMfcJkJjSgZImi A==; X-CSE-ConnectionGUID: co0rktWqTbqUrKO/EU2fVw== X-CSE-MsgGUID: +VzAhy16Qu2jwb+9ktGppQ== X-IronPort-AV: E=McAfee;i="6600,9927,11078"; a="15393490" X-IronPort-AV: E=Sophos;i="6.08,177,1712646000"; d="scan'208";a="15393490" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2024 00:17:32 -0700 X-CSE-ConnectionGUID: FZK3yX4LRkqnQxWI1laz1Q== X-CSE-MsgGUID: /eCxpIRkSS2B0m1cz4vmog== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,177,1712646000"; d="scan'208";a="37336787" Received: from unknown (HELO fedora..) ([10.245.246.159]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 May 2024 00:17:26 -0700 From: =?utf-8?q?Thomas_Hellstr=C3=B6m?= To: intel-xe@lists.freedesktop.org Cc: =?utf-8?q?Thomas_Hellstr=C3=B6m?= , =?utf-8?q?Christian_K=C3=B6nig?= , Somalapuram Amaranath , Matthew Brost , dri-devel@lists.freedesktop.org Subject: [RFC PATCH v3 15/21] drm/exec: Add a snapshot capability Date: Tue, 21 May 2024 09:16:33 +0200 Message-ID: <20240521071639.77614-16-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240521071639.77614-1-thomas.hellstrom@linux.intel.com> References: <20240521071639.77614-1-thomas.hellstrom@linux.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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" When validating a buffer object for submission, we might need to lock a number of object for eviction to make room for the validation. This makes it pretty likely that validation will eventually succeed, since eventually the validating process will hold most dma_resv locks of the buffer objects residing in the memory type being validated for. However, once validation of a single object has succeeded it might not be beneficial to hold on to those locks anymore, and the validator would want to drop the locks of all objects taken during validation. Introduce a drm_exec snapshot functionality that can be used to record the locks held at a certain time, and a restore functionality that restores the drm_exec state to the snapshot by dropping all locks. Snapshots can be nested if needed. Cc: Christian König Cc: Somalapuram Amaranath Cc: Matthew Brost Cc: Signed-off-by: Thomas Hellström --- drivers/gpu/drm/drm_exec.c | 55 +++++++++++++++++++++++++++++++++++++- include/drm/drm_exec.h | 23 +++++++++++++++- 2 files changed, 76 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_exec.c b/drivers/gpu/drm/drm_exec.c index 1383680ffa4a..9eea5d0d3a98 100644 --- a/drivers/gpu/drm/drm_exec.c +++ b/drivers/gpu/drm/drm_exec.c @@ -57,6 +57,7 @@ static void drm_exec_unlock_all(struct drm_exec *exec) struct drm_gem_object *obj; unsigned long index; + WARN_ON(exec->snap); drm_exec_for_each_locked_object_reverse(exec, index, obj) { dma_resv_unlock(obj->resv); drm_gem_object_put(obj); @@ -90,6 +91,7 @@ void drm_exec_init(struct drm_exec *exec, u32 flags, unsigned nr) exec->num_objects = 0; exec->contended = DRM_EXEC_DUMMY; exec->prelocked = NULL; + exec->snap = NULL; } EXPORT_SYMBOL(drm_exec_init); @@ -301,7 +303,6 @@ int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj) goto error_unlock; return 0; - error_unlock: dma_resv_unlock(obj->resv); return ret; @@ -395,5 +396,57 @@ int drm_exec_prepare_array(struct drm_exec *exec, } EXPORT_SYMBOL(drm_exec_prepare_array); +/** + * drm_exec_restore() - Restore the drm_exec state to the point of a snapshot. + * @exec: The drm_exec object with the state. + * @snap: The snapshot state. + * + * Restores the drm_exec object by means of unlocking and dropping references + * to objects locked after the snapshot. + */ +void drm_exec_restore(struct drm_exec *exec, struct drm_exec_snapshot *snap) +{ + struct drm_gem_object *obj; + unsigned int index; + + exec->snap = snap->saved_snap; + + drm_exec_for_each_locked_object_reverse(exec, index, obj) { + if (index + 1 == snap->num_locked) + break; + + dma_resv_unlock(obj->resv); + drm_gem_object_put(obj); + exec->objects[index] = NULL; + } + + exec->num_objects = snap->num_locked; + + if (!exec->prelocked) + exec->prelocked = snap->prelocked; + else + drm_gem_object_put(snap->prelocked); +} +EXPORT_SYMBOL(drm_exec_restore); + +/** + * drm_exec_snapshot() - Take a snapshot of the drm_exec state + * @exec: The drm_exec object with the state. + * @snap: The snapshot state. + * + * Records the @exec state in @snap. The @snap object is typically allocated + * in the stack of the caller. + */ +void drm_exec_snapshot(struct drm_exec *exec, struct drm_exec_snapshot *snap) +{ + snap->num_locked = exec->num_objects; + snap->prelocked = exec->prelocked; + if (snap->prelocked) + drm_gem_object_get(snap->prelocked); + snap->saved_snap = exec->snap; + exec->snap = snap; +} +EXPORT_SYMBOL(drm_exec_snapshot); + MODULE_DESCRIPTION("DRM execution context"); MODULE_LICENSE("Dual MIT/GPL"); diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h index ea0f2117ee0c..0ce4d749511b 100644 --- a/include/drm/drm_exec.h +++ b/include/drm/drm_exec.h @@ -19,7 +19,6 @@ struct drm_exec { * @flags: Flags to control locking behavior */ u32 flags; - /** * @ticket: WW ticket used for acquiring locks */ @@ -49,6 +48,25 @@ struct drm_exec { * @prelocked: already locked GEM object due to contention */ struct drm_gem_object *prelocked; + + /** + * @snap: Pointer to the last snapshot taken or NULL if none. + */ + struct drm_exec_snapshot *snap; +}; + +/** + * struct drm_exec_snapshot - drm_exec snapshot information + */ +struct drm_exec_snapshot { + /** @saved_snap: Pointer to the previous snapshot or NULL. */ + struct drm_exec_snapshot *saved_snap; + + /** @prelocked: Refcounted pointer to the prelocked object at snapshot time. */ + struct drm_gem_object *prelocked; + + /** @num_locked: Number of locked objects at snapshot time. */ + unsigned long num_locked; }; int drm_exec_handle_contended(struct drm_exec *exec); @@ -160,5 +178,8 @@ int drm_exec_prepare_array(struct drm_exec *exec, struct drm_gem_object **objects, unsigned int num_objects, unsigned int num_fences); +void drm_exec_snapshot(struct drm_exec *exec, struct drm_exec_snapshot *snap); +void drm_exec_restore(struct drm_exec *exec, struct drm_exec_snapshot *snap); + #endif