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 9E259F41808 for ; Mon, 9 Mar 2026 15:11:32 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0C1F410E53D; Mon, 9 Mar 2026 15:11:32 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="pNYGUDE7"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1FB9F10E531 for ; Mon, 9 Mar 2026 15:11:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1773069089; bh=w27TMdRFJpx6CB/hnSGjitr+y+Qx5oP+4mBmfM6vXY0=; h=From:To:Cc:Subject:Date:From; b=pNYGUDE7pgmY1yBo3ctOk4BsihwJhRpTNTywpne/L0u24YE8XWDCm+Zxe9fr/Xbqd FF1I8EtO2Nm241ulkFgFLN4B68+lEB+fceMrjw8c4DfyyJn0HSbnw2rmnPO8H4uobF 0wx1T53lOtUwl1UKhWhko+ireWjNhajyXIGQeSEHQueAjliQQ97Bw9YEWrCzmC5h78 aMyuhEgIRcvpLNRxsw/y9k9bzbnpwoXAmP24vPdfgp1GiOiASplo85lChoolgAN0m/ kGgjDMzp0VdpgFyt9gVHAzU5ndH+SemekYXcIX+ZJ7CCJVGg8FR/3k+IpWHwVPtKs2 ttgeyP/i1yN+g== Received: from fedora (unknown [IPv6:2a01:e0a:2c:6930:a2a7:f53:ebb0:945e]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id 0C54117E0FDB; Mon, 9 Mar 2026 16:11:29 +0100 (CET) From: Boris Brezillon To: Boris Brezillon , Steven Price , Liviu Dudau , =?UTF-8?q?Adri=C3=A1n=20Larumbe?= Cc: dri-devel@lists.freedesktop.org, David Airlie , Simona Vetter , Akash Goel , Rob Clark , Sean Paul , Konrad Dybcio , Akhil P Oommen , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Dmitry Osipenko , Chris Diamand , Danilo Krummrich , Matthew Brost , =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Alice Ryhl , Chia-I Wu , kernel@collabora.com Subject: [PATCH v5 0/9] drm/panthor: Add a GEM shrinker Date: Mon, 9 Mar 2026 16:11:10 +0100 Message-ID: <20260309151119.290217-1-boris.brezillon@collabora.com> X-Mailer: git-send-email 2.53.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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" Hello, This is an attempt at adding a GEM shrinker to panthor so the system can finally reclaim GPU memory. This implementation is losely based on the MSM shrinker (which is why I added the MSM maintainers in Cc), and it's relying on the drm_gpuvm eviction/validation infrastructure. I've only done very basic IGT-based [1] and chromium-based (opening a lot of tabs on Aquarium until the system starts reclaiming+swapping out GPU buffers) testing, but I'm posting this early so I can get preliminary feedback on the implementation. If someone knows about better tools/ways to test the shrinker, please let me know. A few words about some design/implementation choices: - No MADVISE support because I want to see if we can live with just transparent reclaim - We considered basing this implementation on the generic shrinker work started by Dmitry [2], but 1. with the activeness/idleness tracking happening at the VM granularity, having per-BO LRUs would caused a lot of list_move()s that are not really needed (the VM as a whole become active/idle, we can track individual BOs) 2. Thomas Zimmermann recently suggested that we should have our own GEM implementation instead of trying to add this extra reclaim complexity to gem-shmem. There are some plans to create a gem-uma (Unified Memory Architecture) lib that would do more than gem-shmem but in a way that doesn't force all its users to pay the overhead (size overhead of the gem object, mostly) for features they don't use. Patch "Part ways with drm_gem_shmem_object" is showing what this component-based lib API could look like if it were to be extracted - At the moment we only support swapout, but we could add an extra flag to specify when buffer content doesn't need to be preserved to avoid the swapout/swapin dance. First candidate for this DISCARD_ON_RECLAIM flag would probably be the tiler heap chunks. - Reclaim uses _try_lock() all the way because of the various lock order inversions between the reclaim path and submission paths. That means we don't try very hard to reclaim hot GPU buffers, but the locking is such a mess that I don't really see a better option to be honest. Changes in v2: - No fundamental changes in this v2, since the feedback I got were more focused on bugs than the overall approach. Check the changelog in each patch for more details. Changes in v3: - Mostly fixes (see the changelog in each patch) Changes in v4: - Only fixes (see the changelog in each patch) Changes in v5: - Only fixes (see the changelog in each patch) Regards, Boris [1]https://gitlab.freedesktop.org/bbrezillon/igt-gpu-tools/-/commit/fc76934a5579767d2aabe787d40e38a17c3f4ea4 [2]https://lkml.org/lkml/2024/1/5/665 Akash Goel (1): drm/panthor: Add a GEM shrinker Boris Brezillon (8): drm/gem: Consider GEM object reclaimable if shrinking fails drm/panthor: Move panthor_gems_debugfs_init() to panthor_gem.c drm/panthor: Group panthor_kernel_bo_xxx() helpers drm/panthor: Don't call drm_gpuvm_bo_extobj_add() if the object is private drm/panthor: Part ways with drm_gem_shmem_object drm/panthor: Lazily allocate pages on mmap() drm/panthor: Split panthor_vm_prepare_map_op_ctx() to prepare for reclaim drm/panthor: Track the number of mmap on a BO drivers/gpu/drm/drm_gem.c | 10 + drivers/gpu/drm/panthor/Kconfig | 1 - drivers/gpu/drm/panthor/panthor_device.c | 11 +- drivers/gpu/drm/panthor/panthor_device.h | 73 ++ drivers/gpu/drm/panthor/panthor_drv.c | 33 +- drivers/gpu/drm/panthor/panthor_fw.c | 16 +- drivers/gpu/drm/panthor/panthor_gem.c | 1421 ++++++++++++++++++---- drivers/gpu/drm/panthor/panthor_gem.h | 136 ++- drivers/gpu/drm/panthor/panthor_mmu.c | 475 ++++++-- drivers/gpu/drm/panthor/panthor_mmu.h | 8 + drivers/gpu/drm/panthor/panthor_sched.c | 9 +- 11 files changed, 1858 insertions(+), 335 deletions(-) -- 2.53.0