From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:50792 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751401AbcJETXK (ORCPT ); Wed, 5 Oct 2016 15:23:10 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u95JIxeu019265 for ; Wed, 5 Oct 2016 15:23:09 -0400 Received: from e24smtp01.br.ibm.com (e24smtp01.br.ibm.com [32.104.18.85]) by mx0a-001b2d01.pphosted.com with ESMTP id 25w2gur45m-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 05 Oct 2016 15:23:09 -0400 Received: from localhost by e24smtp01.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 5 Oct 2016 16:23:06 -0300 Subject: Re: aio: questions with ioctx_alloc() and large num_possible_cpus() To: Benjamin LaHaise References: <20161005174146.GK23336@kvack.org> <737b5bf7-329e-c59d-7601-aea0f4ffbeab@linux.vnet.ibm.com> <20161005181741.GL23336@kvack.org> Cc: Kent Overstreet , Alexander Viro , linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-kernel@vger.kernel.org From: Mauricio Faria de Oliveira Date: Wed, 5 Oct 2016 16:22:02 -0300 MIME-Version: 1.0 In-Reply-To: <20161005181741.GL23336@kvack.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Message-Id: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Ben, On 10/05/2016 03:17 PM, Benjamin LaHaise wrote: > Anything's possible when a local user can run code. [snip] That > said, local users tend not to DoS themselves. Agree. I thought of something that could be particularly related to the aio implementation; but I guess there's nothing so special then. > [snip] It probably makes > sense to implement per-user limits rather than the current global limit, > and maybe even convert them to an rlimit to better fit in with the > available frameworks for managing these things. I see it would be a nice improvement, but unfortunately that's not a task that I can take at the moment. For now, the most I'm able to do is to continue to try to understand whether there's something we can do that may help the small nr_events case to be more on par with the large nr_events case.. or any other beginner-level fixes to the area. :) Thanks again, -- Mauricio Faria de Oliveira IBM Linux Technology Center