From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 03F586B0038 for ; Sat, 18 Nov 2017 23:19:57 -0500 (EST) Received: by mail-pf0-f200.google.com with SMTP id p2so5838041pfk.13 for ; Sat, 18 Nov 2017 20:19:56 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id g5si4308275plk.466.2017.11.18.20.19.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 18 Nov 2017 20:19:55 -0800 (PST) Date: Sat, 18 Nov 2017 20:19:54 -0800 From: Matthew Wilcox Subject: Re: [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for stateless idle loops Message-ID: <20171119041954.GA12039@bombadil.infradead.org> References: <20171101053244.5218-1-slandden@gmail.com> <20171103063544.13383-1-slandden@gmail.com> <20171103090915.uuaqo56phdbt6gnf@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Shawn Landden Cc: Michal Hocko , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org On Fri, Nov 17, 2017 at 08:45:03PM -0800, Shawn Landden wrote: > On Fri, Nov 3, 2017 at 2:09 AM, Michal Hocko wrote: > > On Thu 02-11-17 23:35:44, Shawn Landden wrote: > > > 16 bytes per process is kinda spendy, but I want to keep > > > lru behavior, which mem_score_adj does not allow. When a supervisor, > > > like Android's user input is keeping track this can be done in > > user-space. > > > It could be pulled out of task_struct if an cross-indexing additional > > > red-black tree is added to support pid-based lookup. > > > > This is still an abuse and the patch is wrong. We really do have an API > > to use I fail to see why you do not use it. > > > When I looked at wait_queue_head_t it was 20 byes. 24 bytes actually; the compiler will add 4 bytes of padding between the spinlock and the list_head. But there's one for the entire system. Then you add a 40 byte structure (wait_queue_entry) on the stack for each sleeping process. There's no per-process cost. -- 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