From patchwork Fri Jan 22 15:45:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Auld X-Patchwork-Id: 12039763 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A8CEC433E6 for ; Fri, 22 Jan 2021 15:46:01 +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 EEE4220702 for ; Fri, 22 Jan 2021 15:46:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EEE4220702 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 34AC36EA03; Fri, 22 Jan 2021 15:46:00 +0000 (UTC) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 221CA6E9FB for ; Fri, 22 Jan 2021 15:45:59 +0000 (UTC) IronPort-SDR: qBAj+Y+ay1wlcVn3pRdW6xDJ3Qlh6XTHAbfSY2elag2NDHOuh/WrbpMUWOPDwtLhcUXvvZuAG+ LXIFXDI5TySQ== X-IronPort-AV: E=McAfee;i="6000,8403,9872"; a="179606448" X-IronPort-AV: E=Sophos;i="5.79,366,1602572400"; d="scan'208";a="179606448" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jan 2021 07:45:57 -0800 IronPort-SDR: ikxHz5J0mpmgR6CefdbdI4VHqYMOuUd6FCzTu5LyoH2skX9G5D2bqntehD3p/BIrxdBl7Ln05G HHeJ77a33EJw== X-IronPort-AV: E=Sophos;i="5.79,366,1602572400"; d="scan'208";a="428003980" Received: from lcfenner-mobl1.ger.corp.intel.com (HELO mwauld-desk1.ger.corp.intel.com) ([10.252.20.148]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jan 2021 07:45:56 -0800 From: Matthew Auld To: intel-gfx@lists.freedesktop.org Date: Fri, 22 Jan 2021 15:45:46 +0000 Message-Id: <20210122154547.502685-1-matthew.auld@intel.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH] drm/i915/buddy: document the unused header bits 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" The largest possible order is (63-12), given that our min chunk size is 4K. With that we should only need at most 6 bits to represent all possible orders, giving us back 4 bits for other potential uses. Include a simple selftest to verify this. Signed-off-by: Matthew Auld Reviewed-by: Chris Wilson Reported-by: kernel test robot --- drivers/gpu/drm/i915/i915_buddy.c | 3 ++ drivers/gpu/drm/i915/i915_buddy.h | 7 ++- drivers/gpu/drm/i915/selftests/i915_buddy.c | 47 +++++++++++++++++++++ 3 files changed, 55 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_buddy.c b/drivers/gpu/drm/i915/i915_buddy.c index 20babbdb297d..650613ae2a7b 100644 --- a/drivers/gpu/drm/i915/i915_buddy.c +++ b/drivers/gpu/drm/i915/i915_buddy.c @@ -56,6 +56,9 @@ static struct i915_buddy_block *i915_block_alloc(struct i915_buddy_block *parent block->header |= order; block->parent = parent; + GEM_BUG_ON(block->header & I915_BUDDY_HEADER_UNUSED); + GEM_BUG_ON(order > I915_BUDDY_MAX_ORDER); + return block; } diff --git a/drivers/gpu/drm/i915/i915_buddy.h b/drivers/gpu/drm/i915/i915_buddy.h index ed41f3507cdc..d37e03587637 100644 --- a/drivers/gpu/drm/i915/i915_buddy.h +++ b/drivers/gpu/drm/i915/i915_buddy.h @@ -15,7 +15,9 @@ struct i915_buddy_block { #define I915_BUDDY_ALLOCATED (1 << 10) #define I915_BUDDY_FREE (2 << 10) #define I915_BUDDY_SPLIT (3 << 10) -#define I915_BUDDY_HEADER_ORDER GENMASK_ULL(9, 0) +/* Free to be used, if needed in the future */ +#define I915_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6) +#define I915_BUDDY_HEADER_ORDER GENMASK_ULL(5, 0) u64 header; struct i915_buddy_block *left; @@ -34,7 +36,8 @@ struct i915_buddy_block { struct list_head tmp_link; }; -#define I915_BUDDY_MAX_ORDER I915_BUDDY_HEADER_ORDER +/* Order-zero must be at least PAGE_SIZE */ +#define I915_BUDDY_MAX_ORDER (63 - 12) /* * Binary Buddy System. diff --git a/drivers/gpu/drm/i915/selftests/i915_buddy.c b/drivers/gpu/drm/i915/selftests/i915_buddy.c index 632b912b0bc9..39c470a0e28d 100644 --- a/drivers/gpu/drm/i915/selftests/i915_buddy.c +++ b/drivers/gpu/drm/i915/selftests/i915_buddy.c @@ -727,6 +727,52 @@ static int igt_buddy_alloc_range(void *arg) return err; } +static int igt_buddy_alloc_limit(void *arg) +{ + struct i915_buddy_block *block; + struct i915_buddy_mm mm; + const u64 size = U64_MAX; + int err; + + err = i915_buddy_init(&mm, size, PAGE_SIZE); + if (err) + return err; + + if (mm.max_order != I915_BUDDY_MAX_ORDER) { + pr_err("mm.max_order(%d) != %d\n", + mm.max_order, I915_BUDDY_MAX_ORDER); + err = -EINVAL; + goto out_fini; + } + + block = i915_buddy_alloc(&mm, mm.max_order); + if (IS_ERR(block)) { + err = PTR_ERR(block); + goto out_fini; + } + + if (i915_buddy_block_order(block) != I915_BUDDY_MAX_ORDER) { + pr_err("block order(%d) != %d\n", + i915_buddy_block_order(block), I915_BUDDY_MAX_ORDER); + err = -EINVAL; + goto out_free; + } + + if (i915_buddy_block_size(&mm, block) != rounddown_pow_of_two(size)) { + pr_err("block size(%llu) != %lu\n", + i915_buddy_block_size(&mm, block), + rounddown_pow_of_two(size)); + err = -EINVAL; + goto out_free; + } + +out_free: + i915_buddy_free(&mm, block); +out_fini: + i915_buddy_fini(&mm); + return err; +} + int i915_buddy_mock_selftests(void) { static const struct i915_subtest tests[] = { @@ -735,6 +781,7 @@ int i915_buddy_mock_selftests(void) SUBTEST(igt_buddy_alloc_pathological), SUBTEST(igt_buddy_alloc_smoke), SUBTEST(igt_buddy_alloc_range), + SUBTEST(igt_buddy_alloc_limit), }; return i915_subtests(tests, NULL);