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 12179D2CE17 for ; Wed, 10 Dec 2025 04:32:20 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C9F9E10E65A; Wed, 10 Dec 2025 04:32:19 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="FHyzFEMt"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) by gabe.freedesktop.org (Postfix) with ESMTPS id 19A4910E65A for ; Wed, 10 Dec 2025 04:32:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1765341138; x=1796877138; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=0qjy/tLAAIUPue/uH82wtJwZ2+aiDdk63WL6cdYXfR0=; b=FHyzFEMtyiH2HYWGKuPzyjuvtaM/iL11YNKMK2H/DHNJVLYwD7DPPm5G VZZRef8j0JycmLiqoMN6u7jT4KCaR7Lt34uIBNYadPB8TuExIHmVnq/yS YWuMIUN9M8CFmEAvGKccYpWjztWQS9QYTKh56Fzp7flyqCILiqEairnjN bM46Wkezr8enSkUzlA4tLTtgdhcWvE0cgl6WLQx9RbLEVv46Fx6hZl8zY hktpYLw4iR3wlEgyI4+sdoPNdyNmZ8x6IY6raFmorJ7pPEPIlXwJOELBo jHatATg0n5whH7dCccFCGdU8X4yZcqWUA7nmHtOKfwyNUeb/BN4uiajY4 w==; X-CSE-ConnectionGUID: HNEPsLM+SLy5b/LWddn/nQ== X-CSE-MsgGUID: Zv76AP23SoqTEvcVBzKU7Q== X-IronPort-AV: E=McAfee;i="6800,10657,11637"; a="78000056" X-IronPort-AV: E=Sophos;i="6.20,263,1758610800"; d="scan'208";a="78000056" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Dec 2025 20:32:18 -0800 X-CSE-ConnectionGUID: bHTJnyobSNCRRb7ia5XkEQ== X-CSE-MsgGUID: Hn+I68ciRVOHjtwPM47Q6g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.20,263,1758610800"; d="scan'208";a="196466583" Received: from varungup-desk.iind.intel.com ([10.190.238.71]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Dec 2025 20:32:16 -0800 From: Arvind Yadav To: intel-xe@lists.freedesktop.org Cc: matthew.brost@intel.com, himal.prasad.ghimiray@intel.com, thomas.hellstrom@linux.intel.com, pallavi.mishra@intel.com Subject: [RFC v3 2/8] drm/xe/bo: Add purgeable bo state tracking and field madv to xe_bo Date: Wed, 10 Dec 2025 10:00:46 +0530 Message-ID: <20251210043112.3267620-3-arvind.yadav@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251210043112.3267620-1-arvind.yadav@intel.com> References: <20251210043112.3267620-1-arvind.yadav@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" Add infrastructure for tracking purgeable state of buffer objects. This includes: Introduce enum xe_madv_purgeable_state with three states: - XE_MADV_PURGEABLE_WILLNEED (0): BO is needed and should not be purged. This is the default state for all BOs. - XE_MADV_PURGEABLE_DONTNEED (1): BO is not currently needed and can be purged by the kernel under memory pressure to reclaim resources. Only non-shared BOs can be marked as DONTNEED. - XE_MADV_PURGEABLE_PURGED (2): BO has been purged by the kernel. Accessing a purged BO results in error. Follows i915 semantics where once purged, the BO remains permanently invalid ("once purged, always purged"). Add atomic_t madv field to struct xe_bo for state tracking of purgeable state across concurrent access paths v2: - Add xe_bo_is_purged() helper, improve state documentation V3: - Add the kernel doc(Matthew Brost) - Add the new helpers xe_bo_madv_is_dontneed(Matthew Brost) Cc: Matthew Brost Cc: Thomas Hellström Cc: Himal Prasad Ghimiray Signed-off-by: Arvind Yadav --- drivers/gpu/drm/xe/xe_bo.h | 56 ++++++++++++++++++++++++++++++++ drivers/gpu/drm/xe/xe_bo_types.h | 3 ++ 2 files changed, 59 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h index 8ab4474129c3..1090a60f6ef6 100644 --- a/drivers/gpu/drm/xe/xe_bo.h +++ b/drivers/gpu/drm/xe/xe_bo.h @@ -86,6 +86,28 @@ #define XE_PCI_BARRIER_MMAP_OFFSET (0x50 << XE_PTE_SHIFT) +/** + * enum xe_madv_purgeable_state - Buffer object purgeable state enumeration + * + * This enum defines the possible purgeable states for a buffer object, + * allowing userspace to provide memory usage hints to the kernel for + * better memory management under pressure. + * + * @XE_MADV_PURGEABLE_WILLNEED: The buffer object is needed and should not be purged. + * This is the default state. + * @XE_MADV_PURGEABLE_DONTNEED: The buffer object is not currently needed and can be + * purged by the kernel under memory pressure. + * @XE_MADV_PURGEABLE_PURGED: The buffer object has been purged by the kernel. + * + * Accessing a purged buffer will result in an error. Per i915 semantics, + * once purged, a BO remains permanently invalid and must be destroyed and recreated. + */ +enum xe_madv_purgeable_state { + XE_MADV_PURGEABLE_WILLNEED, + XE_MADV_PURGEABLE_DONTNEED, + XE_MADV_PURGEABLE_PURGED, +}; + struct sg_table; struct xe_bo *xe_bo_alloc(void); @@ -214,6 +236,40 @@ static inline bool xe_bo_is_protected(const struct xe_bo *bo) return bo->pxp_key_instance; } +/** + * xe_bo_is_purged() - Check if buffer object has been purged + * @bo: The buffer object to check + * + * Checks if the buffer object's backing store has been discarded by the + * kernel due to memory pressure after being marked as purgeable (DONTNEED). + * Once purged, the BO cannot be restored and any attempt to use it will fail. + * + * Context: Caller must hold the BO's dma-resv lock + * Return: true if the BO has been purged, false otherwise + */ +static inline bool xe_bo_is_purged(struct xe_bo *bo) +{ + xe_bo_assert_held(bo); + return atomic_read(&bo->madv_purgeable) == XE_MADV_PURGEABLE_PURGED; +} + +/** + * xe_bo_madv_is_dontneed() - Check if BO is marked as DONTNEED + * @bo: The buffer object to check + * + * Checks if userspace has marked this BO as DONTNEED (i.e., its contents + * are not currently needed and can be discarded under memory pressure). + * This is used internally to decide whether a BO is eligible for purging. + * + * Context: Caller must hold the BO's dma-resv lock + * Return: true if the BO is marked DONTNEED, false otherwise + */ +static inline bool xe_bo_madv_is_dontneed(struct xe_bo *bo) +{ + xe_bo_assert_held(bo); + return atomic_read(&bo->madv_purgeable) == XE_MADV_PURGEABLE_DONTNEED; +} + static inline void xe_bo_unpin_map_no_vm(struct xe_bo *bo) { if (likely(bo)) { diff --git a/drivers/gpu/drm/xe/xe_bo_types.h b/drivers/gpu/drm/xe/xe_bo_types.h index d4fe3c8dca5b..57b4dc7012e2 100644 --- a/drivers/gpu/drm/xe/xe_bo_types.h +++ b/drivers/gpu/drm/xe/xe_bo_types.h @@ -108,6 +108,9 @@ struct xe_bo { * from default */ u64 min_align; + + /** @madv_purgeable: user space advise on BO purgeability */ + atomic_t madv_purgeable; }; #endif -- 2.43.0