From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 69A303CCFDE for ; Fri, 10 Jul 2026 21:54:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783720492; cv=none; b=D2xqXZuBJPcid3u5ZOSflSh7LX2dy0OTuLb6uWm2CR/uuYf11rdqbEfoji5wVmJ4g5Gn9vnvEIWwraDvp1as87kNelILicivTYAmkOiGncLRksdO7DV9iBh9SsWGbfq9qvX5qck0bU/74nUaoGBuNzEUsWXwzWvL5OxWeBIEQu4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783720492; c=relaxed/simple; bh=D5ratfSKQyG0DWPv8Mc6SI6ySPvUU7Hy5HH+2ucW/cU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=X7Coaq8JRMNMHpkR0Jopo0SnwVe2r41RarpQOBUwutCLnbjmUuqtBqz+lEGHrMZn74B9qv0W0sIU7iOSn04/FOFjCVIxnNxX0r05qnOAWrdjcrMe7VSNSsYEsy8HcoVY/P3CBQUYGeLRCnnNp594yg3uhv3fu3ECUp1SGHNxS0A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=eCZ2HpBs; arc=none smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="eCZ2HpBs" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1783720490; x=1815256490; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=D5ratfSKQyG0DWPv8Mc6SI6ySPvUU7Hy5HH+2ucW/cU=; b=eCZ2HpBsVtfo72u/8AzIQz4cIVRRwiImlxv4KoHkhooqZk6cE87fU3pF qcXcloTo6URFo6Rr+H3XeaLdET/uWPRBiBgRLedN8Opd28dS8yvf0UZ65 1ffFcHE4/45iSbA1aZDw/xtSCzeDWXwPDNkf/n9Oix4W/2UM8p+H3Zvu2 ENItNPwBrucmh6jyU5csjXbfC4zyXwlBslSc82m92YSw2H2VFCZkkg5rP YetgD3Yk1nfD32PepGQuTjTb+xc8tnEItWT115HQukqrtCZQOIJxjzEJY 34Dmq2LPA99zeUD1a7qs5CIC/7J6XQieURow/8W8qyii4Q3IdhknZM7lq Q==; X-CSE-ConnectionGUID: KRrBG2MmSH6imgoAWULNRw== X-CSE-MsgGUID: OHSOMgFgRq61I8IxS8Tx7g== X-IronPort-AV: E=McAfee;i="6800,10657,11841"; a="83543057" X-IronPort-AV: E=Sophos;i="6.25,154,1779174000"; d="scan'208";a="83543057" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jul 2026 14:54:48 -0700 X-CSE-ConnectionGUID: YNfWI//TTDmFoVpuafDa0Q== X-CSE-MsgGUID: LhcWHhIWTKW/n/x5HX1Nqw== X-ExtLoop1: 1 Received: from gsse-cloud1.jf.intel.com ([10.54.39.91]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jul 2026 14:54:48 -0700 From: Matthew Brost To: intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org Cc: Carlos Santa , Ryan Neph , Christian Koenig , Huang Rui , Matthew Auld , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , linux-kernel@vger.kernel.org, =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= Subject: [PATCH v2 03/33] drm/ttm: Record sub-optimal page order allocations in ttm_tt Date: Fri, 10 Jul 2026 14:54:12 -0700 Message-Id: <20260710215442.2444235-4-matthew.brost@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260710215442.2444235-1-matthew.brost@intel.com> References: <20260710215442.2444235-1-matthew.brost@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When __ttm_pool_alloc() fails to allocate a chunk at the device's beneficial order and falls back to a smaller order, the object ends up backed by a sub-optimal set of pages. Nothing currently records this, so a driver has no way to know an object would benefit from being re-backed with beneficial-order pages later. Add TTM_TT_FLAG_BENEFICIAL_ORDER_FAILED to struct ttm_tt page_flags, cleared at the start of every fresh allocation (in both ttm_pool_alloc() and ttm_pool_restore_and_alloc()). Set it in __ttm_pool_alloc() when an allocation at exactly the beneficial order fails before dropping to a lower order. Drivers can use this hint to queue the buffer object for later defragmentation. Cc: Carlos Santa Cc: Ryan Neph Cc: Christian Koenig Cc: Huang Rui Cc: Matthew Auld Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Simona Vetter Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Cc: Thomas Hellström Assisted-by: GitHub_Copilot:claude-opus-4.8 Signed-off-by: Matthew Brost --- drivers/gpu/drm/ttm/ttm_pool.c | 13 +++++++++++++ include/drm/ttm/ttm_tt.h | 24 +++++++++++++++++++++++- 2 files changed, 36 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index d34592d4dbc7..370d991c9882 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -796,6 +796,7 @@ static int __ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt, struct ttm_pool_alloc_state *alloc, struct ttm_pool_tt_restore *restore) { + const unsigned int beneficial_order = ttm_pool_beneficial_order(pool); enum ttm_caching page_caching; gfp_t gfp_flags = GFP_USER; pgoff_t caching_divide; @@ -846,6 +847,16 @@ static int __ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt, /* If that fails, lower the order if possible and retry. */ if (!p) { if (order) { + /* + * Failing to allocate at the device's beneficial + * order means we are about to back this object + * with a sub-optimal (smaller order) set of + * pages. Record it so the driver can later try to + * defragment the object back to beneficial order. + */ + if (beneficial_order && order == beneficial_order) + tt->page_flags |= + TTM_TT_FLAG_BENEFICIAL_ORDER_FAILED; --order; page_caching = tt->caching; allow_pools = true; @@ -910,6 +921,7 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt, if (WARN_ON(ttm_tt_is_backed_up(tt))) return -EINVAL; + tt->page_flags &= ~TTM_TT_FLAG_BENEFICIAL_ORDER_FAILED; ttm_pool_alloc_state_init(tt, &alloc); return __ttm_pool_alloc(pool, tt, ctx, &alloc, NULL); @@ -942,6 +954,7 @@ int ttm_pool_restore_and_alloc(struct ttm_pool *pool, struct ttm_tt *tt, if (!restore) { gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; + tt->page_flags &= ~TTM_TT_FLAG_BENEFICIAL_ORDER_FAILED; ttm_pool_alloc_state_init(tt, &alloc); if (ctx->gfp_retry_mayfail) gfp |= __GFP_RETRY_MAYFAIL; diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h index 406437ad674b..ce7533677d77 100644 --- a/include/drm/ttm/ttm_tt.h +++ b/include/drm/ttm/ttm_tt.h @@ -90,6 +90,14 @@ struct ttm_tt { * TTM_TT_FLAG_BACKED_UP: TTM internal only. This is set if the * struct ttm_tt has been (possibly partially) backed up. * + * TTM_TT_FLAG_BENEFICIAL_ORDER_FAILED: Set by the TTM pool allocator + * when at least one chunk that could have been allocated at the pool's + * beneficial order had to fall back to a smaller order. This indicates + * that a sub-optimal set of pages was chosen for this object, and can + * be used by drivers to queue the buffer object for later + * defragmentation. Drivers should access this via the + * ttm_tt_is_beneficial_order_failed() helper. + * * TTM_TT_FLAG_PRIV_POPULATED: TTM internal only. DO NOT USE. This is * set by TTM after ttm_tt_populate() has successfully returned, and is * then unset when TTM calls ttm_tt_unpopulate(). @@ -101,8 +109,9 @@ struct ttm_tt { #define TTM_TT_FLAG_EXTERNAL_MAPPABLE BIT(3) #define TTM_TT_FLAG_DECRYPTED BIT(4) #define TTM_TT_FLAG_BACKED_UP BIT(5) +#define TTM_TT_FLAG_BENEFICIAL_ORDER_FAILED BIT(6) -#define TTM_TT_FLAG_PRIV_POPULATED BIT(6) +#define TTM_TT_FLAG_PRIV_POPULATED BIT(7) uint32_t page_flags; /** @num_pages: Number of pages in the page array. */ uint32_t num_pages; @@ -179,6 +188,19 @@ static inline void ttm_tt_clear_backed_up(struct ttm_tt *tt) tt->page_flags &= ~TTM_TT_FLAG_BACKED_UP; } +/** + * ttm_tt_is_beneficial_order_failed() - Whether the tt is backed at a + * sub-optimal page order + * @tt: The struct ttm_tt. + * + * Return: true if the pool allocator had to fall back below the pool's + * beneficial order when backing this tt, false otherwise. + */ +static inline bool ttm_tt_is_beneficial_order_failed(const struct ttm_tt *tt) +{ + return tt->page_flags & TTM_TT_FLAG_BENEFICIAL_ORDER_FAILED; +} + /** * ttm_tt_create * -- 2.34.1