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 0597DC433F5 for ; Wed, 2 Feb 2022 13:04:22 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1A2D589123; Wed, 2 Feb 2022 13:04:22 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1C60610E161 for ; Wed, 2 Feb 2022 13:04:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643807061; x=1675343061; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=rGPIVCE31WBToTCyGgVTy97nhIFVoQxzTzDGebqbuZI=; b=Q6P2dUjdlq3tkYijjetnlUNHm+NlqvQE2rWnpDrKlaTH+o7dR/OnT3DP NYvQFiLtPWafTiA2s4DIkcFQxKRUp//kBWHjvOOO/bkskFoZ4QFPw9vKM 4knXJk9RN0CGTJIhjwndLu/CR2EEkPHWbnMgm7F7z/CNmTz61wvsbs4Jc RFWq1nlpk8ryVZSarSSKH84UZ9XKAdcmesshqhhKajgKoFr7lZ8L4UP0O 1Yo/c5G0GLlMNAKLQhB4W7F5CSQJZUdeBaxoccZJm7shwQsShTxxwE7XS 6SWNPgsV3gFLmGN/wuUHKDRIvyPcjBIGlX3YSEGUpRBmWIPxVOqKR0V6l A==; X-IronPort-AV: E=McAfee;i="6200,9189,10245"; a="311218116" X-IronPort-AV: E=Sophos;i="5.88,336,1635231600"; d="scan'208";a="311218116" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Feb 2022 05:04:19 -0800 X-IronPort-AV: E=Sophos;i="5.88,336,1635231600"; d="scan'208";a="565980535" Received: from dolandox-mobl1.ger.corp.intel.com (HELO [10.213.211.99]) ([10.213.211.99]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Feb 2022 05:04:18 -0800 Message-ID: Date: Wed, 2 Feb 2022 13:04:16 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH 1/2] drm/mm: Add an iterator to optimally walk over holes for an allocation Content-Language: en-US To: Vivek Kasireddy , dri-devel@lists.freedesktop.org References: <20220202011358.1409946-1-vivek.kasireddy@intel.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc In-Reply-To: <20220202011358.1409946-1-vivek.kasireddy@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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" On 02/02/2022 01:13, Vivek Kasireddy wrote: > This iterator relies on drm_mm_first_hole() and drm_mm_next_hole() > functions to identify suitable holes for an allocation of a given > size by efficently traversing the rbtree associated with the given > allocator. > > It replaces the for loop in drm_mm_insert_node_in_range() and can > also be used by drm drivers to quickly identify holes of a certain > size within a given range. > > Suggested-by: Tvrtko Ursulin > Signed-off-by: Vivek Kasireddy > --- > drivers/gpu/drm/drm_mm.c | 28 ++++++++++++---------------- > include/drm/drm_mm.h | 32 ++++++++++++++++++++++++++++++++ > 2 files changed, 44 insertions(+), 16 deletions(-) > > diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c > index 8257f9d4f619..416c849c10e5 100644 > --- a/drivers/gpu/drm/drm_mm.c > +++ b/drivers/gpu/drm/drm_mm.c > @@ -352,10 +352,10 @@ static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size) > return node; > } > > -static struct drm_mm_node * > -first_hole(struct drm_mm *mm, > - u64 start, u64 end, u64 size, > - enum drm_mm_insert_mode mode) > +struct drm_mm_node * > +drm_mm_first_hole(struct drm_mm *mm, > + u64 start, u64 end, u64 size, > + enum drm_mm_insert_mode mode) > { > switch (mode) { > default: > @@ -374,6 +374,7 @@ first_hole(struct drm_mm *mm, > hole_stack); > } > } > +EXPORT_SYMBOL(drm_mm_first_hole); > > /** > * DECLARE_NEXT_HOLE_ADDR - macro to declare next hole functions > @@ -410,11 +411,11 @@ static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \ > DECLARE_NEXT_HOLE_ADDR(next_hole_high_addr, rb_left, rb_right) > DECLARE_NEXT_HOLE_ADDR(next_hole_low_addr, rb_right, rb_left) > > -static struct drm_mm_node * > -next_hole(struct drm_mm *mm, > - struct drm_mm_node *node, > - u64 size, > - enum drm_mm_insert_mode mode) > +struct drm_mm_node * > +drm_mm_next_hole(struct drm_mm *mm, > + struct drm_mm_node *node, > + u64 size, > + enum drm_mm_insert_mode mode) > { > switch (mode) { > default: > @@ -432,6 +433,7 @@ next_hole(struct drm_mm *mm, > return &node->hole_stack == &mm->hole_stack ? NULL : node; > } > } > +EXPORT_SYMBOL(drm_mm_next_hole); May need to add kerneldoc since first/next_hole are now exported, or perhaps double underscore them if DRM core allows that approach to kind of signify "it is exported by shouldn't really be used"? Question for dri-devel I guess. > > /** > * drm_mm_reserve_node - insert an pre-initialized node > @@ -520,7 +522,6 @@ int drm_mm_insert_node_in_range(struct drm_mm * const mm, > { > struct drm_mm_node *hole; > u64 remainder_mask; > - bool once; > > DRM_MM_BUG_ON(range_start > range_end); > > @@ -533,13 +534,8 @@ int drm_mm_insert_node_in_range(struct drm_mm * const mm, > if (alignment <= 1) > alignment = 0; > > - once = mode & DRM_MM_INSERT_ONCE; > - mode &= ~DRM_MM_INSERT_ONCE; > - > remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0; > - for (hole = first_hole(mm, range_start, range_end, size, mode); > - hole; > - hole = once ? NULL : next_hole(mm, hole, size, mode)) { > + drm_mm_for_each_best_hole(hole, mm, range_start, range_end, size, mode) { > u64 hole_start = __drm_mm_hole_node_start(hole); > u64 hole_end = hole_start + hole->hole_size; > u64 adj_start, adj_end; > diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h > index ac33ba1b18bc..5055447697fa 100644 > --- a/include/drm/drm_mm.h > +++ b/include/drm/drm_mm.h > @@ -322,6 +322,17 @@ static inline u64 __drm_mm_hole_node_end(const struct drm_mm_node *hole_node) > return list_next_entry(hole_node, node_list)->start; > } > > +struct drm_mm_node * > +drm_mm_first_hole(struct drm_mm *mm, > + u64 start, u64 end, u64 size, > + enum drm_mm_insert_mode mode); > + > +struct drm_mm_node * > +drm_mm_next_hole(struct drm_mm *mm, > + struct drm_mm_node *node, > + u64 size, > + enum drm_mm_insert_mode mode); > + > /** > * drm_mm_hole_node_end - computes the end of the hole following @node > * @hole_node: drm_mm_node which implicitly tracks the following hole > @@ -400,6 +411,27 @@ static inline u64 drm_mm_hole_node_end(const struct drm_mm_node *hole_node) > 1 : 0; \ > pos = list_next_entry(pos, hole_stack)) > > +/** > + * drm_mm_for_each_best_hole - iterator to optimally walk over all holes >= @size > + * @pos: &drm_mm_node used internally to track progress > + * @mm: &drm_mm allocator to walk > + * @range_start: start of the allowed range for the allocation > + * @range_end: end of the allowed range for the allocation > + * @size: size of the allocation > + * @mode: fine-tune the allocation search > + * > + * This iterator walks over all holes suitable for the allocation of given > + * @size in a very efficient manner. It is implemented by calling > + * drm_mm_first_hole() and drm_mm_next_hole() which identify the > + * appropriate holes within the given range by efficently traversing the > + * rbtree associated with @mm. > + */ > +#define drm_mm_for_each_best_hole(pos, mm, range_start, range_end, size, mode) \ Probably should not have "best" in the name since the mode is passed in by the caller. > + for (pos = drm_mm_first_hole(mm, range_start, range_end, size, mode); \ > + pos; \ > + pos = mode & DRM_MM_INSERT_ONCE ? \ > + NULL : drm_mm_next_hole(mm, hole, size, mode)) I think you would need to modify the first/next_hole to mask out DRM_MM_INSERT_ONCE, otherwise it probably does not work as it stands. Regards, Tvrtko > + > /* > * Basic range manager support (drm_mm.c) > */