From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3x72YN71xRzDqgF for ; Thu, 13 Jul 2017 01:14:32 +1000 (AEST) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v6CEx8EG097250 for ; Wed, 12 Jul 2017 11:14:30 -0400 Received: from e35.co.us.ibm.com (e35.co.us.ibm.com [32.97.110.153]) by mx0b-001b2d01.pphosted.com with ESMTP id 2bnn25uwn5-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 12 Jul 2017 11:14:30 -0400 Received: from localhost by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 12 Jul 2017 09:14:29 -0600 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Date: Wed, 12 Jul 2017 12:15:10 -0300 From: victora To: "Aneesh Kumar K.V" Cc: Victor Aoqui , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au Subject: Re: [PATCH] powerpc/mm: Implemented default_hugepagesz verification for powerpc In-Reply-To: References: <20170703200559.3743-1-victora@br.ibm.com> <1f549637-773a-868c-effd-5614e85aa892@linux.vnet.ibm.com> Message-Id: <231a6e252020968b7eff8dd25dbb126b@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Em 2017-07-05 13:03, victora escreveu: > Em 2017-07-05 01:26, Aneesh Kumar K.V escreveu: >> On Tuesday 04 July 2017 01:35 AM, Victor Aoqui wrote: >>> Implemented default hugepage size verification (default_hugepagesz=) >>> in order to allow allocation of defined number of pages (hugepages=) >>> only for supported hugepage sizes. >>> >>> Signed-off-by: Victor Aoqui >>> --- >>> arch/powerpc/mm/hugetlbpage.c | 15 +++++++++++++++ >>> 1 file changed, 15 insertions(+) >>> >>> diff --git a/arch/powerpc/mm/hugetlbpage.c >>> b/arch/powerpc/mm/hugetlbpage.c >>> index a4f33de..464e72e 100644 >>> --- a/arch/powerpc/mm/hugetlbpage.c >>> +++ b/arch/powerpc/mm/hugetlbpage.c >>> @@ -797,6 +797,21 @@ static int __init hugepage_setup_sz(char *str) >>> } >>> __setup("hugepagesz=", hugepage_setup_sz); >>> >>> +static int __init default_hugepage_setup_sz(char *str) >>> +{ >>> + unsigned long long size; >>> + >>> + size = memparse(str, &str); >>> + >>> + if (add_huge_page_size(size) != 0) { >>> + hugetlb_bad_size(); >>> + pr_err("Invalid default huge page size >>> specified(%llu)\n", size); >>> + } >>> + >>> + return 1; >>> +} >>> +__setup("default_hugepagesz=", default_hugepage_setup_sz); >> >> isn't that a behavior change in what we have now ? . Right now if size >> specified is not supported, we fallback to HPAGE_SIZE. > > Yes, it is. However, is this a correct behavior? If we specify an > unsupported value, for example default_hugepagesz=1M and > hugepages=1000, 1M will be ignored and 1000 pages of 16M (arch > default) will be allocated. This could lead to non-expected out of of > memory/performance issue. > >> >> mm/hugetlb.c >> >> if (!size_to_hstate(default_hstate_size)) { >> default_hstate_size = HPAGE_SIZE; >> if (!size_to_hstate(default_hstate_size)) >> hugetlb_add_hstate(HUGETLB_PAGE_ORDER); >> } >> >> >>> + >>> struct kmem_cache *hugepte_cache; >>> static int __init hugetlbpage_init(void) >>> { >>> >> >> Even if we want to do this, this should be done in generic code and >> should not be powerpc specific >> > > The verification of supported powerpc hugepage size (hugepagesz=) is > being performed on add_huge_page_size(), which is currently defined in > arch/powerpc/mm/hugetlbpage.c. I think it makes more sense to > implement default_hugepagesz= verification on arch/powerpc, don't you > think? > >> -aneesh Hi Aneesh, Did you have time to review the comments above? Thanks Victor