From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-187.mta1.migadu.com (out-187.mta1.migadu.com [95.215.58.187]) (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 29C891B5310 for ; Thu, 29 Aug 2024 16:20:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724948440; cv=none; b=esd0s3uYlDl7Do/HjZzYMc14CQDTFP6FFCPUU56+aIK3N+x8I6+Kh36aB9X8eUr+1OozOu8xp93pfDmMAAEiuvkkU9DvdVLdL7nRSRahAo/M6kEFfp1Iy2Lu/zNV3B8A969JiKt9oeCqE9hIgWPguCtzADdhFs6tYUvFzchCTN4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724948440; c=relaxed/simple; bh=7U6Nmbh114G96KtGYBVDLAbK4d6lfvn2XssOHsbTrO4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tDLATdPTsl8FXmz/7L2wYHGwQ098WY1doDZixmVA1eRI46HVgbJXq7dBoP9SCMur25CXwWxpXoaQTZFDCyzyl3XxdvJYLbQm3z+UgtsFzy2lpBX3gT/HYq0w8opX2kcxbeq87VkFg3T1Eay9EI2fufKaX0UmCDWV93A4lMAj4B4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=qHFy6zh3; arc=none smtp.client-ip=95.215.58.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="qHFy6zh3" Date: Thu, 29 Aug 2024 16:20:28 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1724948436; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=TqnxVaBjgZfealincCR2Zh7tFE8qlNsIgLvhONXdZ1c=; b=qHFy6zh3aSVycnfwMPa+TGK1S86Y8eGqQ+lER+GugiPaxKDt1qqI5UdERHZKWVvCiRP0uJ mAc/ne4Mph2X8TNL/fp/s9L8udkV8DXLIkPNwe4JgfQchKfQE2x81o0YNdAjhxdcFzEtRz eepH/wLlvDilwHkme1dwivldLtoMDfI= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Roman Gushchin To: Shakeel Butt Cc: Vlastimil Babka , Andrew Morton , Johannes Weiner , Michal Hocko , Muchun Song , David Rientjes , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Eric Dumazet , "David S . Miller" , Jakub Kicinski , Paolo Abeni , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Meta kernel team , cgroups@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH v2] memcg: add charging of already allocated slab objects Message-ID: References: <20240827235228.1591842-1-shakeel.butt@linux.dev> <9fb06d9b-dec5-4300-acef-bbce51a9a0c1@suse.cz> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT On Thu, Aug 29, 2024 at 09:10:53AM -0700, Shakeel Butt wrote: > On Thu, Aug 29, 2024 at 11:42:10AM GMT, Vlastimil Babka wrote: > > On 8/28/24 01:52, Shakeel Butt wrote: > > > At the moment, the slab objects are charged to the memcg at the > > > allocation time. However there are cases where slab objects are > > > allocated at the time where the right target memcg to charge it to is > > > not known. One such case is the network sockets for the incoming > > > connection which are allocated in the softirq context. > > > > > > Couple hundred thousand connections are very normal on large loaded > > > server and almost all of those sockets underlying those connections get > > > allocated in the softirq context and thus not charged to any memcg. > > > However later at the accept() time we know the right target memcg to > > > charge. Let's add new API to charge already allocated objects, so we can > > > have better accounting of the memory usage. > > > > > > To measure the performance impact of this change, tcp_crr is used from > > > the neper [1] performance suite. Basically it is a network ping pong > > > test with new connection for each ping pong. > > > > > > The server and the client are run inside 3 level of cgroup hierarchy > > > using the following commands: > > > > > > Server: > > > $ tcp_crr -6 > > > > > > Client: > > > $ tcp_crr -6 -c -H ${server_ip} > > > > > > If the client and server run on different machines with 50 GBPS NIC, > > > there is no visible impact of the change. > > > > > > For the same machine experiment with v6.11-rc5 as base. > > > > > > base (throughput) with-patch > > > tcp_crr 14545 (+- 80) 14463 (+- 56) > > > > > > It seems like the performance impact is within the noise. > > > > > > Link: https://github.com/google/neper [1] > > > Signed-off-by: Shakeel Butt > > > --- > > > v1: https://lore.kernel.org/all/20240826232908.4076417-1-shakeel.butt@linux.dev/ > > > Changes since v1: > > > - Correctly handle large allocations which bypass slab > > > - Rearrange code to avoid compilation errors for !CONFIG_MEMCG builds > > > > > > RFC: https://lore.kernel.org/all/20240824010139.1293051-1-shakeel.butt@linux.dev/ > > > Changes since the RFC: > > > - Added check for already charged slab objects. > > > - Added performance results from neper's tcp_crr > > > > > > include/linux/slab.h | 1 + > > > mm/slub.c | 51 +++++++++++++++++++++++++++++++++ > > > net/ipv4/inet_connection_sock.c | 5 ++-- > > > 3 files changed, 55 insertions(+), 2 deletions(-) > > > > I can take the v3 in slab tree, if net people ack? > > Thanks. > > > > > BTW, will this be also useful for Linus's idea of charging struct files only > > after they exist? But IIRC there was supposed to be also a part where we > > have a way to quickly determine if we're not over limit (while allowing some > > overcharge to make it quicker). It should work and speed up the case when we can drop the object before charging. I'd suggest to implement it in a separate change though. Thanks!