From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oa0-f41.google.com (mail-oa0-f41.google.com [209.85.219.41]) by kanga.kvack.org (Postfix) with ESMTP id 63E296B0082 for ; Tue, 1 Apr 2014 18:49:42 -0400 (EDT) Received: by mail-oa0-f41.google.com with SMTP id j17so12214735oag.0 for ; Tue, 01 Apr 2014 15:49:42 -0700 (PDT) Received: from mail-oa0-x22c.google.com (mail-oa0-x22c.google.com [2607:f8b0:4003:c02::22c]) by mx.google.com with ESMTPS id j4si22420obw.88.2014.04.01.15.49.41 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 01 Apr 2014 15:49:41 -0700 (PDT) Received: by mail-oa0-f44.google.com with SMTP id n16so12028175oag.17 for ; Tue, 01 Apr 2014 15:49:41 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20140401144801.603c288674ab8f417b42a043@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> <1396308332.18499.25.camel@buesod1.americas.hpqcorp.net> <20140331170546.3b3e72f0.akpm@linux-foundation.org> <1396371699.25314.11.camel@buesod1.americas.hpqcorp.net> <1396377083.25314.17.camel@buesod1.americas.hpqcorp.net> <1396386062.25314.24.camel@buesod1.americas.hpqcorp.net> <20140401142947.927642a408d84df27d581e36@linux-foundation.org> <20140401144801.603c288674ab8f417b42a043@linux-foundation.org> From: KOSAKI Motohiro Date: Tue, 1 Apr 2014 18:49:21 -0400 Message-ID: Subject: Re: [PATCH] ipc,shm: increase default size for shmmax Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Davidlohr Bueso , Manfred Spraul , aswin@hp.com, LKML , "linux-mm@kvack.org" On Tue, Apr 1, 2014 at 5:48 PM, Andrew Morton wrote: > On Tue, 1 Apr 2014 17:41:54 -0400 KOSAKI Motohiro wrote: > >> >> > Hmmm so 0 won't really work because it could be weirdly used to disable >> >> > shm altogether... we cannot go to some negative value either since we're >> >> > dealing with unsigned, and cutting the range in half could also hurt >> >> > users that set the limit above that. So I was thinking of simply setting >> >> > SHMMAX to ULONG_MAX and be done with it. Users can then set it manually >> >> > if they want a smaller value. >> >> > >> >> > Makes sense? >> >> >> >> I don't think people use 0 for disabling. but ULONG_MAX make sense to me too. >> > >> > Distros could have set it to [U]LONG_MAX in initscripts ten years ago >> > - less phone calls, happier customers. And they could do so today. >> > >> > But they haven't. What are the risks of doing this? >> >> I have no idea really. But at least I'm sure current default is much worse. >> >> 1. Solaris changed the default to total-memory/4 since Solaris 10 for DB. >> http://www.postgresql.org/docs/9.1/static/kernel-resources.html >> >> 2. RHEL changed the default to very big size since RHEL5 (now it is >> 64GB). Even tough many box don't have 64GB memory at that time. > > Ah-hah, that's interesting info. > > Let's make the default 64GB? 64GB is infinity at that time, but it no longer near infinity today. I like very large or total memory proportional number. But I'm open. Please let me see if anyone know the disadvantage of very large value. -- 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