From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id D6BD76B0038 for ; Mon, 20 Nov 2017 03:35:51 -0500 (EST) Received: by mail-wr0-f200.google.com with SMTP id v8so5560492wrd.21 for ; Mon, 20 Nov 2017 00:35:51 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id z37si1771543edd.59.2017.11.20.00.35.50 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 20 Nov 2017 00:35:50 -0800 (PST) Date: Mon, 20 Nov 2017 09:35:48 +0100 From: Michal Hocko Subject: Re: [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for stateless idle loops Message-ID: <20171120083548.stupram6kpi5iu7i@dhcp22.suse.cz> 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: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org On Fri 17-11-17 20:45:03, 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: > > > It is common for services to be stateless around their main event loop. > > > If a process sets PR_SET_IDLE to PR_IDLE_MODE_KILLME then it > > > signals to the kernel that epoll_wait() and friends may not complete, > > > and the kernel may send SIGKILL if resources get tight. > > > > > > See my systemd patch: https://github.com/shawnl/systemd/tree/prctl > > > > > > Android uses this memory model for all programs, and having it in the > > > kernel will enable integration with the page cache (not in this > > > series). > > > > > > 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. I do not understand. What I meant to say is that we do have a proper user api to hint OOM killer decisions. -- Michal Hocko SUSE Labs -- 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