From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id D284C6B0003 for ; Wed, 21 Feb 2018 15:54:30 -0500 (EST) Received: by mail-wr0-f197.google.com with SMTP id v16so2422396wrv.14 for ; Wed, 21 Feb 2018 12:54:30 -0800 (PST) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id 199si17765868wmj.52.2018.02.21.12.54.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Feb 2018 12:54:29 -0800 (PST) Date: Wed, 21 Feb 2018 12:54:26 -0800 From: Andrew Morton Subject: Re: [PATCH v2 0/3] Directed kmem charging Message-Id: <20180221125426.464f894d29a0b6e525b2e3be@linux-foundation.org> In-Reply-To: References: <20180221030101.221206-1-shakeelb@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Shakeel Butt Cc: Christopher Lameter , Jan Kara , Amir Goldstein , Pekka Enberg , David Rientjes , Joonsoo Kim , Greg Thelen , Johannes Weiner , Michal Hocko , Vladimir Davydov , Mel Gorman , Vlastimil Babka , linux-fsdevel , Linux MM , Cgroups , LKML On Wed, 21 Feb 2018 09:18:35 -0800 Shakeel Butt wrote: > On Wed, Feb 21, 2018 at 8:09 AM, Christopher Lameter wrote: > > Another way to solve this is to switch the user context right? > > > > Isnt it possible to avoid these patches if do the allocation in another > > task context instead? > > > > Sorry, can you please explain what you mean by 'switch the user > context'. Is there any example in kernel which does something similar? > > Another way is by adding a field 'remote_memcg_to_charge' in > task_struct and set it before the allocation and in memcontrol.c, > first check if current->remote_memcg_to_charge is set otherwise use > the memcg of current. Also if we provide a wrapper to do that for the > user, there will be a lot less plumbing. > > Please let me know if you prefer this approach. That would be a lot simpler. Passing function arguments via task_struct is a bit dirty but is sometimes sooo effective. You should've seen how much mess task_struct.journal_info avoided! And reclaim_state. And one always wonders whether we should do a local save/restore before modifying the task_struct field, so it nests. What do others think? Maybe we can rename task_struct.reclaim_state to `struct task_mm_state *task_mm_state", add remote_memcg_to_charge to struct task_mm_state and avoid bloating the task_struct? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org