Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933536AbcCHAN3 (ORCPT ); Mon, 7 Mar 2016 19:13:29 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:45116 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933952AbcCHAER (ORCPT ); Mon, 7 Mar 2016 19:04:17 -0500 Date: Mon, 7 Mar 2016 16:03:59 -0800 From: Andrew Morton To: Jan Stancek Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, n-horiguchi@ah.jp.nec.com, mike kravetz , hillf zj , kirill shutemov , dave hansen , paul gortmaker Subject: Re: [PATCH] mm/hugetlb: use EOPNOTSUPP in hugetlb sysctl handlers Message-Id: <20160307160359.c8cde2e7cc4a52234f212c0d@linux-foundation.org> In-Reply-To: <983257005.5372143.1457165390827.JavaMail.zimbra@redhat.com> References: <20160304133807.72ede1000b9bf0b846d2fb87@linux-foundation.org> <983257005.5372143.1457165390827.JavaMail.zimbra@redhat.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1059 Lines: 23 On Sat, 5 Mar 2016 03:09:50 -0500 (EST) Jan Stancek wrote: > > > Replace ENOTSUPP with EOPNOTSUPP. If hugepages are not supported, > > > this value is propagated to userspace. EOPNOTSUPP is part of uapi > > > and is widely supported by libc libraries. > > > > hm, what is the actual user-visible effect of this change? Does it fix > > some misbehaviour? > > > > It gives nicer message to user, rather than: > # cat /proc/sys/vm/nr_hugepages > cat: /proc/sys/vm/nr_hugepages: Unknown error 524 > > And also LTP's proc01 test was failing because this ret code (524) > was unexpected: > proc01 1 TFAIL : proc01.c:396: read failed: /proc/sys/vm/nr_hugepages: errno=???(524): Unknown error 524 > proc01 2 TFAIL : proc01.c:396: read failed: /proc/sys/vm/nr_hugepages_mempolicy: errno=???(524): Unknown error 524 > proc01 3 TFAIL : proc01.c:396: read failed: /proc/sys/vm/nr_overcommit_hugepages: errno=???(524): Unknown error 524 > Ah, OK, thanks. "Unknown error 524" is rather rude. I'll queue this for 4.5.