From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id BF7AB1A2C20 for ; Tue, 15 Sep 2015 13:44:32 +1000 (AEST) Received: from e23smtp02.au.ibm.com (e23smtp02.au.ibm.com [202.81.31.144]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 17F4F140291 for ; Tue, 15 Sep 2015 13:44:31 +1000 (AEST) Received: from /spool/local by e23smtp02.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 15 Sep 2015 13:44:28 +1000 Received: from d23relay09.au.ibm.com (d23relay09.au.ibm.com [9.185.63.181]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 353552BB0057 for ; Tue, 15 Sep 2015 13:44:26 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t8F3iIcb55836840 for ; Tue, 15 Sep 2015 13:44:26 +1000 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t8F3hrAR008307 for ; Tue, 15 Sep 2015 13:43:54 +1000 Message-ID: <55F793E8.7050909@linux.vnet.ibm.com> Date: Tue, 15 Sep 2015 09:13:36 +0530 From: Anshuman Khandual MIME-Version: 1.0 To: Nishanth Aravamudan , "Aneesh Kumar K.V" CC: linuxppc-dev@ozlabs.org, mikey@neuling.org Subject: Re: [RFC] powerpc/hugetlb: Add warning message when gpage allocation request fails References: <1442212051-15235-1-git-send-email-khandual@linux.vnet.ibm.com> <87egi1f7t6.fsf@linux.vnet.ibm.com> <20150914162426.GA54362@linux.vnet.ibm.com> In-Reply-To: <20150914162426.GA54362@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 09/14/2015 09:54 PM, Nishanth Aravamudan wrote: > On 14.09.2015 [18:59:25 +0530], Aneesh Kumar K.V wrote: >> > Anshuman Khandual writes: >> > >>> > > When a 16GB huge page is requested on POWER platform through kernel command >>> > > line interface, it silently fails because of the lack of any gigantic pages >>> > > on the system which the platform should have communicated through 16GB memory >>> > > blocks in the device tree during boot time. For example >>> > > >>> > > [ 0.480940] HugeTLB registered 16 GB page size, pre-allocated 0 pages >>> > > [ 0.480945] HugeTLB registered 16 MB page size, pre-allocated 16 pages >>> > > >>> > > This adds a warning message during alloc_bootmem_huge_page request both on >>> > > book3e and book3s powerpc platforms. After this change >>> > > >>> > > [ 0.000000] Gigantic HugeTLB page not available >>> > > [ 0.473417] HugeTLB registered 16 GB page size, pre-allocated 0 pages >>> > > [ 0.473423] HugeTLB registered 16 MB page size, pre-allocated 16 pages >> > >> > >> > That info is already part of the second line isn't it ? ie >> > >> > [ 0.473417] HugeTLB registered 16 GB page size, pre-allocated 0 pages >> > >> > pre-allocated 0 pages indicate we didn't allocate anything. So why do we >> > need to add more details fo kernel output ? > Agreed, the '0 pages' message indicates we failed to pre-allocate any > pages. The 'pre-allocate' messages are specifically about the kernel > command-line requests for hugepages. > > Not sure I understand the motivation for this? The motivation was just to add a cause to the failure of allocation of requested 16G huge pages. I think "pre-allocated 0 pages" does not hint about the cause of the failure.