From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) (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 5D4C0242D6C for ; Tue, 5 Aug 2025 07:49:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754380153; cv=none; b=EGN8/iBJcFiu5bZdY3pILQyCzgsTK0heHEvbC4EvYvcDuZtf98g+70HfKT2QeXWUkGNWeSsfE5ozD4BuC5fsqWdDlstYZyAd1xfGRBVgw2zGEkcGZAUMx4UZ7nKXDA7xjXaDVQae8+dmi59ByleDe2J9TmPJsL2LpLqOa/x1Nyk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754380153; c=relaxed/simple; bh=1xk6aLT08ICrU8/eFnZZFifBDZYD9pMX/wD7oKxxNfM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=l8VESfoB2gcBaqyOcGyiHT5Q2H5HBh2bFoleAyDeUP5KQlVEUqnjnp5/YxArlmbAT56BYv1vgMXuqjVnbbzOg1Xp2mwcRyPyr8TQvtoU8kvradZEQ98HUYOii67MqswfeEJP9CCCcl5/FAdFlQ7TvjDOX4andf/VTpFS0jqCfdo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=fuUaY7RO; arc=none smtp.client-ip=192.198.163.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none 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="fuUaY7RO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1754380151; x=1785916151; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=1xk6aLT08ICrU8/eFnZZFifBDZYD9pMX/wD7oKxxNfM=; b=fuUaY7RO4+fDRyQf5UnBaWfup12EfdwK9OegE2FwuXtE1SK6PY5BPn2t ZZTDDQH0FLg1O4Jo4Jbm6RAAStHRvHXWGLnjnszeRkEzAYA8ebpvjv6Fx s8eAxLjndEHKDkiT9lXHSgjliN50rOclIV345zY9gqxSxOkO2/SiApBta koacQ1lC61DbdNqbotegeGu+Io56fzSeMdMLW1ukCqactbd0oHtqjL7U8 6o2A8sJhO3Qf3CR752QMwYK+fLI0izZUN7jIqFdSjsJevbKzdj6ZbBblP 8pv3WBv3U95oiDXrxUd/F2a0750RT8heWe1n/lHgjd/REde+I62i/Y6wj A==; X-CSE-ConnectionGUID: cao4jGYuTlm+m3RqOyGyuw== X-CSE-MsgGUID: o6vn85aiQKieb8qAAyx8wA== X-IronPort-AV: E=McAfee;i="6800,10657,11512"; a="56741784" X-IronPort-AV: E=Sophos;i="6.17,265,1747724400"; d="scan'208";a="56741784" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Aug 2025 00:49:10 -0700 X-CSE-ConnectionGUID: /PBRBPlQTMuf4BNk9E7UNA== X-CSE-MsgGUID: XfE+Mv47Q2epk38YexRrCg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.17,265,1747724400"; d="scan'208";a="168572594" Received: from cpetruta-mobl1.ger.corp.intel.com (HELO fedora) ([10.245.245.229]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Aug 2025 00:49:09 -0700 From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= To: intel-xe@lists.freedesktop.org Cc: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , melvyn , Summers Stuart , stable@vger.kernel.org Subject: [PATCH v2] drm/xe: Defer buffer object shrinker write-backs and GPU waits Date: Tue, 5 Aug 2025 09:48:42 +0200 Message-ID: <20250805074842.11359-1-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: stable@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 the xe buffer-object shrinker allows GPU waits and write-back, (typically from kswapd), perform multiple passes, skipping subsequent passes if the shrinker number of scanned objects target is reached. 1) Without GPU waits and write-back 2) Without write-back 3) With both GPU-waits and write-back This is to avoid stalls and costly write- and readbacks unless they are really necessary. v2: - Don't test for scan completion twice. (Stuart Summers) - Update tags. Reported-by: melvyn Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/5557 Cc: Summers Stuart Fixes: 00c8efc3180f ("drm/xe: Add a shrinker for xe bos") Cc: # v6.15+ Signed-off-by: Thomas Hellström --- drivers/gpu/drm/xe/xe_shrinker.c | 51 +++++++++++++++++++++++++++++--- 1 file changed, 47 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_shrinker.c b/drivers/gpu/drm/xe/xe_shrinker.c index 1c3c04d52f55..90244fe59b59 100644 --- a/drivers/gpu/drm/xe/xe_shrinker.c +++ b/drivers/gpu/drm/xe/xe_shrinker.c @@ -54,10 +54,10 @@ xe_shrinker_mod_pages(struct xe_shrinker *shrinker, long shrinkable, long purgea write_unlock(&shrinker->lock); } -static s64 xe_shrinker_walk(struct xe_device *xe, - struct ttm_operation_ctx *ctx, - const struct xe_bo_shrink_flags flags, - unsigned long to_scan, unsigned long *scanned) +static s64 __xe_shrinker_walk(struct xe_device *xe, + struct ttm_operation_ctx *ctx, + const struct xe_bo_shrink_flags flags, + unsigned long to_scan, unsigned long *scanned) { unsigned int mem_type; s64 freed = 0, lret; @@ -93,6 +93,48 @@ static s64 xe_shrinker_walk(struct xe_device *xe, return freed; } +/* + * Try shrinking idle objects without writeback first, then if not sufficient, + * try also non-idle objects and finally if that's not sufficient either, + * add writeback. This avoids stalls and explicit writebacks with light or + * moderate memory pressure. + */ +static s64 xe_shrinker_walk(struct xe_device *xe, + struct ttm_operation_ctx *ctx, + const struct xe_bo_shrink_flags flags, + unsigned long to_scan, unsigned long *scanned) +{ + bool no_wait_gpu = true; + struct xe_bo_shrink_flags save_flags = flags; + s64 lret, freed; + + swap(no_wait_gpu, ctx->no_wait_gpu); + save_flags.writeback = false; + lret = __xe_shrinker_walk(xe, ctx, save_flags, to_scan, scanned); + swap(no_wait_gpu, ctx->no_wait_gpu); + if (lret < 0 || *scanned >= to_scan) + return lret; + + freed = lret; + if (!ctx->no_wait_gpu) { + lret = __xe_shrinker_walk(xe, ctx, save_flags, to_scan, scanned); + if (lret < 0) + return lret; + freed += lret; + if (*scanned >= to_scan) + return freed; + } + + if (flags.writeback) { + lret = __xe_shrinker_walk(xe, ctx, flags, to_scan, scanned); + if (lret < 0) + return lret; + freed += lret; + } + + return freed; +} + static unsigned long xe_shrinker_count(struct shrinker *shrink, struct shrink_control *sc) { @@ -199,6 +241,7 @@ static unsigned long xe_shrinker_scan(struct shrinker *shrink, struct shrink_con runtime_pm = xe_shrinker_runtime_pm_get(shrinker, true, 0, can_backup); shrink_flags.purge = false; + lret = xe_shrinker_walk(shrinker->xe, &ctx, shrink_flags, nr_to_scan, &nr_scanned); if (lret >= 0) -- 2.50.1