Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759341AbcCEIKO (ORCPT ); Sat, 5 Mar 2016 03:10:14 -0500 Received: from mx5-phx2.redhat.com ([209.132.183.37]:56947 "EHLO mx5-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751709AbcCEIKI (ORCPT ); Sat, 5 Mar 2016 03:10:08 -0500 Date: Sat, 5 Mar 2016 03:09:50 -0500 (EST) From: Jan Stancek To: Andrew Morton 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 Message-ID: <983257005.5372143.1457165390827.JavaMail.zimbra@redhat.com> In-Reply-To: <20160304133807.72ede1000b9bf0b846d2fb87@linux-foundation.org> References: <20160304133807.72ede1000b9bf0b846d2fb87@linux-foundation.org> Subject: Re: [PATCH] mm/hugetlb: use EOPNOTSUPP in hugetlb sysctl handlers MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.34.26.57] X-Mailer: Zimbra 8.0.6_GA_5922 (ZimbraWebClient - FF44 (Win)/8.0.6_GA_5922) Thread-Topic: mm/hugetlb: use EOPNOTSUPP in hugetlb sysctl handlers Thread-Index: 6ZWPOnTR8Jsvro37lXD/6edVynF5HA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1520 Lines: 36 ----- Original Message ----- > 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" > > Sent: Friday, 4 March, 2016 10:38:07 PM > Subject: Re: [PATCH] mm/hugetlb: use EOPNOTSUPP in hugetlb sysctl handlers > > On Thu, 3 Mar 2016 11:02:51 +0100 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 Regards, Jan