From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f178.google.com (mail-ob0-f178.google.com [209.85.214.178]) by kanga.kvack.org (Postfix) with ESMTP id CC5946B0035 for ; Mon, 31 Mar 2014 19:25:34 -0400 (EDT) Received: by mail-ob0-f178.google.com with SMTP id wp18so10269122obc.9 for ; Mon, 31 Mar 2014 16:25:34 -0700 (PDT) Received: from g4t3426.houston.hp.com (g4t3426.houston.hp.com. [15.201.208.54]) by mx.google.com with ESMTPS id sm4si13294682obb.4.2014.03.31.16.25.34 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 31 Mar 2014 16:25:34 -0700 (PDT) Message-ID: <1396308332.18499.25.camel@buesod1.americas.hpqcorp.net> Subject: Re: [PATCH] ipc,shm: increase default size for shmmax From: Davidlohr Bueso Date: Mon, 31 Mar 2014 16:25:32 -0700 In-Reply-To: <20140331161308.6510381345cb9a1b419d5ec0@linux-foundation.org> References: <1396235199.2507.2.camel@buesod1.americas.hpqcorp.net> <20140331143217.c6ff958e1fd9944d78507418@linux-foundation.org> <1396306773.18499.22.camel@buesod1.americas.hpqcorp.net> <20140331161308.6510381345cb9a1b419d5ec0@linux-foundation.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Manfred Spraul , aswin@hp.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, 2014-03-31 at 16:13 -0700, Andrew Morton wrote: > On Mon, 31 Mar 2014 15:59:33 -0700 Davidlohr Bueso wrote: > > > > > > > - Shouldn't there be a way to alter this namespace's shm_ctlmax? > > > > Unfortunately this would also add the complexity I previously mentioned. > > But if the current namespace's shm_ctlmax is too small, you're screwed. > Have to shut down the namespace all the way back to init_ns and start > again. > > > > - What happens if we just nuke the limit altogether and fall back to > > > the next check, which presumably is the rlimit bounds? > > > > afaik we only have rlimit for msgqueues. But in any case, while I like > > that simplicity, it's too late. Too many workloads (specially DBs) rely > > heavily on shmmax. Removing it and relying on something else would thus > > cause a lot of things to break. > > It would permit larger shm segments - how could that break things? It > would make most or all of these issues go away? > So sysadmins wouldn't be very happy, per man shmget(2): EINVAL A new segment was to be created and size < SHMMIN or size > SHMMAX, or no new segment was to be created, a segment with given key existed, but size is greater than the size of that segment. Thanks, Davidlohr -- 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