From patchwork Mon Oct 18 09:10:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Matthew Auld X-Patchwork-Id: 12565423 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 03BD5C433FE for ; Mon, 18 Oct 2021 09:12:27 +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 B5A3560EE3 for ; Mon, 18 Oct 2021 09:12:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B5A3560EE3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=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 62A556E9BB; Mon, 18 Oct 2021 09:12:08 +0000 (UTC) Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by gabe.freedesktop.org (Postfix) with ESMTPS id 09AC76E9B3; Mon, 18 Oct 2021 09:12:02 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10140"; a="209001414" X-IronPort-AV: E=Sophos;i="5.85,381,1624345200"; d="scan'208";a="209001414" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Oct 2021 02:11:56 -0700 X-IronPort-AV: E=Sophos;i="5.85,381,1624345200"; d="scan'208";a="443330274" Received: from cscleary-mobl.ger.corp.intel.com (HELO mwauld-desk1.intel.com) ([10.252.13.221]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Oct 2021 02:11:55 -0700 From: Matthew Auld To: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org, =?utf-8?q?Thomas_Hellstr=C3=B6m?= Subject: [PATCH v9 5/8] drm/i915: add some kernel-doc for shrink_pin and friends Date: Mon, 18 Oct 2021 10:10:52 +0100 Message-Id: <20211018091055.1998191-5-matthew.auld@intel.com> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20211018091055.1998191-1-matthew.auld@intel.com> References: <20211018091055.1998191-1-matthew.auld@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" Attempt to document shrink_pin and the other relevant interfaces that interact with it, before we start messing with it. Signed-off-by: Matthew Auld Cc: Thomas Hellström Reviewed-by: Thomas Hellström --- .../gpu/drm/i915/gem/i915_gem_object_types.h | 24 +++++++++++++- drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 31 +++++++++++++++++++ 2 files changed, 54 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h index 7dd5f804aab3..f4233c4e8d2e 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h @@ -461,6 +461,28 @@ struct drm_i915_gem_object { * instead go through the pin/unpin interfaces. */ atomic_t pages_pin_count; + + /** + * @shrink_pin: Prevents the pages from being made visible to + * the shrinker, while the shrink_pin is non-zero. Most users + * should pretty much never have to care about this, outside of + * some special use cases. + * + * By default most objects will start out as visible to the + * shrinker(if I915_GEM_OBJECT_IS_SHRINKABLE) as soon as the + * backing pages are attached to the object, like in + * __i915_gem_object_set_pages(). They will then be removed the + * shrinker list once the pages are released. + * + * The @shrink_pin is incremented by calling + * i915_gem_object_make_unshrinkable(), which will also remove + * the object from the shrinker list, if the pin count was zero. + * + * Callers will then typically call + * i915_gem_object_make_shrinkable() or + * i915_gem_object_make_purgeable() to decrement the pin count, + * and make the pages visible again. + */ atomic_t shrink_pin; /** @@ -522,7 +544,7 @@ struct drm_i915_gem_object { struct i915_gem_object_page_iter get_dma_page; /** - * Element within i915->mm.unbound_list or i915->mm.bound_list, + * Element within i915->mm.shrink_list or i915->mm.purge_list, * locked by i915->mm.obj_lock. */ struct list_head link; diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c index ae2a8d54b7a4..66121fedc655 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c @@ -463,6 +463,16 @@ void i915_gem_shrinker_taints_mutex(struct drm_i915_private *i915, #define obj_to_i915(obj__) to_i915((obj__)->base.dev) +/** + * i915_gem_object_make_unshrinkable - Hide the object from the shrinker. By + * default all object types that support shrinking(see IS_SHRINKABLE), will also + * make the object visible to the shrinker after allocating the system memory + * pages. + * @obj: The GEM object. + * + * This is typically used for special kernel internal objects that can't be + * easily processed by the shrinker, like if they are perma-pinned. + */ void i915_gem_object_make_unshrinkable(struct drm_i915_gem_object *obj) { struct drm_i915_private *i915 = obj_to_i915(obj); @@ -513,12 +523,33 @@ static void __i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj, spin_unlock_irqrestore(&i915->mm.obj_lock, flags); } +/** + * i915_gem_object_make_shrinkable - Move the object to the tail of the + * shrinkable list. Objects on this list might be swapped out. Used with + * WILLNEED objects. + * @obj: The GEM object. + * + * MUST only be called on objects which have backing pages. + * + * MUST be balanced with previous call to i915_gem_object_make_unshrinkable(). + */ void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj) { __i915_gem_object_make_shrinkable(obj, &obj_to_i915(obj)->mm.shrink_list); } +/** + * i915_gem_object_make_purgeable - Move the object to the tail of the purgeable + * list. Used with DONTNEED objects. Unlike with shrinkable objects, the + * shrinker will attempt to discard the backing pages, instead of trying to swap + * them out. + * @obj: The GEM object. + * + * MUST only be called on objects which have backing pages. + * + * MUST be balanced with previous call to i915_gem_object_make_unshrinkable(). + */ void i915_gem_object_make_purgeable(struct drm_i915_gem_object *obj) { __i915_gem_object_make_shrinkable(obj,