From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.13]) (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 4D92A43BDC9; Thu, 23 Jul 2026 10:04:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784801060; cv=none; b=gkpIrHDS1Bu7s6nVsw2F+P8abRgC6/IfW9pn/kTKiCwHLzh6gEnS+hgnvlYGprMHN2TY1g1IA/6LdkEpLLDMSFHORYH5dfDQJeakH63caErAOfKt3ryCxf4gpT1Aij9cjMcQDz/ExW2PDUHFv04aaXT3oKIkQXaj+WHYlrCs33o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784801060; c=relaxed/simple; bh=/k5TklTHou5l2dBOb2sTQtk7OujtNVKbrhR2IlqNeZ4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=T/lmE2TJtjHzcWkbZLo0WQoN33a1QWMXded7WudFbwL3mbb7HcV6S2F/Zm6QM1lC0G3pBVvVdXUFiWFuAhfDF3oGXOOwSmgIKAHt+SFrtgBy6ZJlfoqSxwR1AXiRUVCnkceA7HLz6b6862NTCsRODM+H2616+DIGPXNQXiNfPGg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=f8MFlBfK; arc=none smtp.client-ip=192.198.163.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="f8MFlBfK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1784801058; x=1816337058; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=/k5TklTHou5l2dBOb2sTQtk7OujtNVKbrhR2IlqNeZ4=; b=f8MFlBfKZy84K7ABB6MgiYi7Os/wJwwvps0L9N47wBXklxyHJZH3YjhE VLIDGeYZ263p0N/V3yQDA4jsKxXDR5Kq/jQSr4foSpnu7oV4nCrE0pjEn YjdlFevwcoUxFPsZaLA7x65Chcy21vhLW6K0vTsGjUl8tmZ7BL44+zXpR 4ePGTR+/HIMV9/dAOXmteapzGsFK3roB/+U7tXdxzaf2YqGYI9asp0XQC LrH1BQRWJQYnMQ6VuaRoXUihOkeh0EydAR/g/lLbkAh/jzd8lYEIjw/cu kCLgepsCqBBUIjtMt6oUt8Lg5CbAwWKHxD2D3z9IRhUR+UROR3M6eX7V3 w==; X-CSE-ConnectionGUID: 4jAVx0ztQL+GvlHgAdisFQ== X-CSE-MsgGUID: V1/673BtRVupNv7l81vPAA== X-IronPort-AV: E=McAfee;i="6800,10657,11854"; a="87991837" X-IronPort-AV: E=Sophos;i="6.25,180,1779174000"; d="scan'208";a="87991837" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2026 03:04:17 -0700 X-CSE-ConnectionGUID: /jUMWDEQRdmamFTezA5kHQ== X-CSE-MsgGUID: JR7PUPQPQTijYEq6o8dobg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,180,1779174000"; d="scan'208";a="254984847" Received: from conormcd-mobl2.ger.corp.intel.com (HELO fedora) ([10.245.244.122]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2026 03:04:12 -0700 From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= To: intel-xe@lists.freedesktop.org Cc: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Natalie Vock , Johannes Weiner , Tejun Heo , =?UTF-8?q?Michal=20Koutn=C3=BD?= , cgroups@vger.kernel.org, Huang Rui , Matthew Brost , Matthew Auld , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Simona Vetter , David Airlie , =?UTF-8?q?Christian=20K=C3=B6nig?= , Thadeu Lima de Souza Cascardo , Alex Deucher , Rodrigo Vivi , dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH v8 0/6] Add reclaim to the dmem cgroup controller Date: Thu, 23 Jul 2026 12:03:44 +0200 Message-ID: <20260723100350.16895-1-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: cgroups@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 writing a "max" limit lower than the current usage, the existing code silently failed. This series aims to improve on that by returning -EBUSY on failure and also attempt to synchronously reclaim device memory to push the usage under the new max limit to avoid the error. Patch 1 fixes a pre-existing amdgpu_vram_mgr_init() error path Patch 2 introduces struct dmem_cgroup_init for extensible region registration. Patch 3 implements and documents a reclaim callback interface for the dmem controller. Patch 4 implements a TTM reclaim callback. Patches 5-6 hook up the reclaim callback to the dmem cgroup-aware drivers xe and amdgpu. v2: - Remove the error propagation that was in a previous series (Maarten) - A number of updates in patch 1. See its commit message for details (Maarten) v3: - Add patch 1 fixing a pre-existing amdgpu_vram_mgr_init() error path bug where drmm_cgroup_register_region() was called before INIT_LIST_HEAD() and gpu_buddy_init(), causing a kernel panic on failure. (Sashiko-bot) - Use an rwsem to protect reclaim callback registration and region unregister against concurrent reclaim invocations. (Sashiko-bot) - Fix ttm_resource_manager_set_dmem_region() storing an error pointer in man->cg unconditionally. (Sashiko-bot) - Fix kernel-doc function name format for ttm_bo_evict_cgroup() and ttm_resource_manager_set_dmem_region(). v4: - Rebased on drm-tip; dropped the XE_PL_STOLEN guard in the xe patch as stolen memory uses a separate TTM manager. v5: - Add patch 2 introducing struct dmem_cgroup_init to make the dmem_cgroup_register_region() API extensible without adding positional arguments in the future. - Use nonblock=true in reset_all_resource_limits() to avoid sleeping inside rcu_read_lock() in dmemcs_offline(). (Sashiko-bot) - Compare usage against the truncated limit stored in cnt.max, not the original u64. (Sashiko-bot) - Use DMEM_MAX_RECLAIM_RETRIES (16) retry budget instead of 5, matching the memcg controller; only -ENOSPC (no progress) counts against the budget, other errors abort immediately. - Handle NULL region in ttm_resource_manager_set_dmem_region() to clear the reclaim callback, preventing use-after-free when the manager is torn down while the dmem region outlives it. (Sashiko-bot) - Return 0 on any eviction progress; reserve -ENOSPC for zero progress. - Clear the reclaim callback in xe and amdgpu fini paths to prevent use-after-free after driver unbind with open DRM file descriptors. (Sashiko-bot) - Register xe fini devres action before drmm_cgroup_register_region() so LIFO teardown runs unregister first, draining callbacks before the manager is destroyed. (Sashiko-bot) - Switch amdgpu to explicit dmem_cgroup_unregister_region() at the top of amdgpu_vram_mgr_fini() before any manager teardown, since amdgpu's fini is called explicitly during driver unbind before drmm cleanup. (Sashiko-bot) - Wrap the xe reclaim callback with drm_dev_enter()/drm_dev_exit() to prevent TTM reclaim from running after driver unbind. v6: - Move the ops check inside down_read() in set_resource_max(), guarded by region->unregistered, to close a UAF race against dmem_cgroup_unregister_region(). (Sashiko-bot) - Fix dmem_cgroup_ops->reclaim docstring: -ENOSPC is retried up to DMEM_MAX_RECLAIM_RETRIES times, not an immediate stop. (Sashiko-bot) - Fix mgr->cg_region never being assigned in amdgpu_vram_mgr_init(), causing dmem_cgroup_unregister_region() in fini to silently no-op. (Sashiko-bot) - Reorder amdgpu_vram_mgr_fini() to call set_used(false) and evict_all() before dmem_cgroup_unregister_region(), so ttm_resource_free() can uncharge via man->cg during eviction; clear man->cg after unregister. (Sashiko-bot) v7: - Replace the per-region rw_semaphore with a static SRCU domain (dmemcg_srcu). SRCU is a better fit: it avoids per-region lock overhead on every reclaim call, and synchronize_srcu() at unregister time is a rare, shutdown-time operation. (Maarten) - Trim in-function comments to focus on what rather than how. - Switch back to drmm_cgroup_register_region() with a drm_dev_enter/ exit guard in the reclaim callback (matching xe), rather than manual register/unregister. drm_dev_unplug() fires before vram_mgr_fini(), so drm_dev_enter() returning false prevents any reclaim from touching the manager during teardown. This also fixes the "vram" name collision on multi-GPU systems, since drmm_cgroup_register_region() automatically prefixes with "drm//". (Sashiko-bot) v8: - Fix ttm_resource_manager_set_dmem_region() using IS_ERR_OR_NULL(), which skipped the assignment for a NULL region and thus never cleared man->cg. Use IS_ERR() so that a NULL region detaches the region as the kernel-doc and the v5 changelog intended. (Sashiko-bot) - Move the amdgpu dmem cgroup region teardown back into amdgpu_vram_mgr_fini() with an explicit dmem_cgroup_unregister_region() after evict_all(), keeping the drm_dev_enter() guard. The v7 drmm-only approach left a use-after-free on the probe-error teardown path, where drm_dev_unplug() is never called so the drm_dev_enter() guard stays open while drm_driver.release destroys the manager before the drmm action unregisters the region. (Sashiko-bot) User-space tests are at https://patchwork.freedesktop.org/series/163935/ Test-with: 20260428065411.4222-1-thomas.hellstrom@linux.intel.com Thomas Hellström (6): drm/amdgpu: Fix init ordering in amdgpu_vram_mgr_init() cgroup/dmem: Introduce struct dmem_cgroup_init for region initialization cgroup/dmem: Add reclaim callback for lowering max below current usage drm/ttm: Hook up a cgroup-aware reclaim callback for the dmem controller drm/xe: Wire up dmem cgroup reclaim for VRAM manager drm/amdgpu: Wire up dmem cgroup reclaim for VRAM manager drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 52 ++++++++++- drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.h | 3 + drivers/gpu/drm/drm_drv.c | 8 +- drivers/gpu/drm/ttm/ttm_bo.c | 95 +++++++++++++++++++- drivers/gpu/drm/ttm/ttm_bo_util.c | 3 +- drivers/gpu/drm/ttm/ttm_resource.c | 52 +++++++++++ drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 53 +++++++++-- include/drm/drm_drv.h | 4 +- include/drm/ttm/ttm_bo.h | 10 +++ include/drm/ttm/ttm_resource.h | 7 ++ include/linux/cgroup_dmem.h | 38 +++++++- kernel/cgroup/dmem.c | 90 +++++++++++++++---- 13 files changed, 380 insertions(+), 37 deletions(-) -- 2.55.0