From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 94E7C3DB63C; Tue, 7 Jul 2026 10:00:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783418439; cv=none; b=f6BxthAR2Sg0aKG6osRkgd09fb4kLBhKpNoPMlIpXZSSIKWfq3dS7uqi/ux90qT4VV3Gn/FviP74Y2Oga6K0jlavxC/RppWIeSM4xm/pdXPsYcdoc+HMEhkxQ8mBEUWoNGoK3JL5TeCGrdjkoP/tIQncl6aQbgAbACdttP7k/hI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783418439; c=relaxed/simple; bh=0yR72GiJj1ZuQanz9GmH0xgCa0XSMaMr4QJoXWVgvkc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hR9WGzWMBDKWNq/8OGXWRc/lKL7eUvKtx03N6DsKb+2kmxpxINsQEfx3IJH75Ncws5sM4NTJSv4IWPu86NsQy55T1fNePDsNb0l1ckXEFNGumosgsTZ3w6+rqdc8zoRoo/nhvp3Kzghv8FG7FO+3ZAYSII9CklvoJR3y6AKgDFk= 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=gxHJGbdg; arc=none smtp.client-ip=192.198.163.7 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="gxHJGbdg" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1783418437; x=1814954437; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=0yR72GiJj1ZuQanz9GmH0xgCa0XSMaMr4QJoXWVgvkc=; b=gxHJGbdgXd8WGv/MIlQGtWhuehNcjCFqM951pI8YB8gMFLiaJRFLQKHg H67h5PKXuyKeOLYcBDSfwrRA3xu4vYub3PA4lqmLeXiUl1QSz6N7B7MqG nfZLw5FxqWPQua2qWcbT1SL7ZZRuosSEKoAMjTDdpF9gzNed04xPa2uYh vZ2wtTMncWEvbttVfMY4RAy4JYa6ijfdeicPrFTzE9C0hX2ZrAuLCb6aJ 15ns7yXXhwYEWsU/Q/mxcpPe4w2ASXgNNcIKmN1xZbkNo2to4BhMbkFKI 95a/EfcAlJUv9S/5uf0Lif7brKlLqM/2zp+vaK4yJRAwCbSxZsaEYmfcx w==; X-CSE-ConnectionGUID: eoWMJMkeSEycPkypkTje9w== X-CSE-MsgGUID: em+FTJzcT4iKcG98OJlcVA== X-IronPort-AV: E=McAfee;i="6800,10657,11839"; a="109603474" X-IronPort-AV: E=Sophos;i="6.25,153,1779174000"; d="scan'208";a="109603474" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2026 03:00:37 -0700 X-CSE-ConnectionGUID: 3G9dJ2bPSIeby/mx6IrECA== X-CSE-MsgGUID: TP4HqTkZTyyjuLeG+19bXA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,153,1779174000"; d="scan'208";a="252880536" Received: from ettammin-mobl3.ger.corp.intel.com (HELO [10.245.244.223]) ([10.245.244.223]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2026 03:00:32 -0700 Message-ID: <6317e0b2-1534-4be1-8c58-fa9d2ad54b20@linux.intel.com> Date: Tue, 7 Jul 2026 12:01:12 +0200 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 3/6] cgroup/dmem: Add reclaim callback for lowering max below current usage To: Tejun Heo , =?UTF-8?Q?Thomas_Hellstr=C3=B6m?= Cc: intel-xe@lists.freedesktop.org, Natalie Vock , Johannes Weiner , =?UTF-8?Q?Michal_Koutn=C3=BD?= , cgroups@vger.kernel.org, Huang Rui , Matthew Brost , Matthew Auld , Maxime Ripard , Thomas Zimmermann , Simona Vetter , David Airlie , =?UTF-8?Q?Christian_K=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 References: <20260703130541.2686-1-thomas.hellstrom@linux.intel.com> <20260703130541.2686-4-thomas.hellstrom@linux.intel.com> Content-Language: en-US From: Maarten Lankhorst In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hey, On 7/6/26 21:25, Tejun Heo wrote: > Hello, > > On Fri, Jul 03, 2026 at 03:05:38PM +0200, Thomas Hellström wrote: >> Also honor O_NONBLOCK so that if that flag is set during the >> max value write, no reclaim is initiated. The idea is to avoid >> charging the reclaim cost to the writer of the max value. > > Is this really necessary? I'm not necessarily against it but this is trivial > to work around from userspace and feels like a gratuitous addition. What's > the use case? The usecase is similar to the usecase in memcg's max/high, it allows the controller to lower the limit, but move the penalty for lowering the limit to the affected cgroups instead of making the controlling process block, especially when changing a lot of limits dynamically this can make a difference. Kind regards, ~Maarten Lankhorst