From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B5E4C433E1 for ; Mon, 6 Jul 2020 22:14:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A9D77206E9 for ; Mon, 6 Jul 2020 22:14:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9D77206E9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=hisilicon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2F1086B000D; Mon, 6 Jul 2020 18:14:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2A1816B0010; Mon, 6 Jul 2020 18:14:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 190D46B0022; Mon, 6 Jul 2020 18:14:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0068.hostedemail.com [216.40.44.68]) by kanga.kvack.org (Postfix) with ESMTP id EFB3C6B000D for ; Mon, 6 Jul 2020 18:14:21 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 99274181AEF09 for ; Mon, 6 Jul 2020 22:14:21 +0000 (UTC) X-FDA: 77009055522.25.look35_2b0213026eaf Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 4FCFE1804E3A8 for ; Mon, 6 Jul 2020 22:14:21 +0000 (UTC) X-HE-Tag: look35_2b0213026eaf X-Filterd-Recvd-Size: 5008 Received: from huawei.com (szxga03-in.huawei.com [45.249.212.189]) by imf20.hostedemail.com (Postfix) with ESMTP for ; Mon, 6 Jul 2020 22:14:20 +0000 (UTC) Received: from dggemi404-hub.china.huawei.com (unknown [172.30.72.57]) by Forcepoint Email with ESMTP id 2A032ACAB1B20B52FFF3; Tue, 7 Jul 2020 06:14:17 +0800 (CST) Received: from DGGEMI525-MBS.china.huawei.com ([169.254.6.177]) by dggemi404-hub.china.huawei.com ([10.3.17.142]) with mapi id 14.03.0487.000; Tue, 7 Jul 2020 06:14:10 +0800 From: "Song Bao Hua (Barry Song)" To: Roman Gushchin CC: "akpm@linux-foundation.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Linuxarm , Mike Kravetz , Jonathan Cameron Subject: RE: [PATCH] mm/hugetlb: avoid hardcoding while checking if cma is reserved Thread-Topic: [PATCH] mm/hugetlb: avoid hardcoding while checking if cma is reserved Thread-Index: AQHWU3HjjsPjy1jnSk6RkQtfiUWhe6j6kUUAgACKkEA= Date: Mon, 6 Jul 2020 22:14:10 +0000 Message-ID: References: <20200706084405.14236-1-song.bao.hua@hisilicon.com> <20200706214808.GB152560@carbon.lan> In-Reply-To: <20200706214808.GB152560@carbon.lan> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.126.201.98] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: 4FCFE1804E3A8 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > -----Original Message----- > From: Roman Gushchin [mailto:guro@fb.com] > Sent: Tuesday, July 7, 2020 9:48 AM > To: Song Bao Hua (Barry Song) > Cc: akpm@linux-foundation.org; linux-mm@kvack.org; > linux-kernel@vger.kernel.org; Linuxarm ; Mike > Kravetz ; Jonathan Cameron > > Subject: Re: [PATCH] mm/hugetlb: avoid hardcoding while checking if cma i= s > reserved >=20 > On Mon, Jul 06, 2020 at 08:44:05PM +1200, Barry Song wrote: >=20 > Hello, Barry! >=20 > > hugetlb_cma[0] can be NULL due to various reasons, for example, node0 h= as > > no memory. Thus, NULL hugetlb_cma[0] doesn't necessarily mean cma is no= t > > enabled. gigantic pages might have been reserved on other nodes. >=20 > Just curious, is it a real-life problem you've seen? If so, I wonder how > you're using the hugetlb_cma option, and what's the outcome? Yes. It is kind of stupid but I once got a board on which node0 has no DDR though node1 and node3 have memory. I actually prefer we get cma size of per node by: cma size of one node =3D hugetlb_cma/ (nodes with memory) rather than: cma size of one node =3D hugetlb_cma/ (all online nodes) but unfortunately, or the N_MEMORY infrastructures are not ready yet. I mea= n: for_each_node_state(nid, N_MEMORY) { int res; size =3D min(per_node, hugetlb_cma_size - reserved); size =3D round_up(size, PAGE_SIZE << order); res =3D cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order, 0, false, "hugetlb", &hugetlb_cma[nid], nid); ... } >=20 > > > > Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepag= es > using cma") > > Cc: Roman Gushchin > > Cc: Mike Kravetz > > Cc: Jonathan Cameron > > Signed-off-by: Barry Song > > --- > > mm/hugetlb.c | 18 +++++++++++++++--- > > 1 file changed, 15 insertions(+), 3 deletions(-) > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > index 57ece74e3aae..603aa854aa89 100644 > > --- a/mm/hugetlb.c > > +++ b/mm/hugetlb.c > > @@ -2571,9 +2571,21 @@ static void __init > hugetlb_hstate_alloc_pages(struct hstate *h) > > > > for (i =3D 0; i < h->max_huge_pages; ++i) { > > if (hstate_is_gigantic(h)) { > > - if (IS_ENABLED(CONFIG_CMA) && hugetlb_cma[0]) { > > - pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip > boot time allocation\n"); > > - break; > > + if (IS_ENABLED(CONFIG_CMA)) { > > + int nid; > > + bool cma_reserved =3D false; > > + > > + for_each_node_state(nid, N_ONLINE) { > > + if (hugetlb_cma[nid]) { > > + pr_warn_once("HugeTLB: hugetlb_cma is > reserved," > > + "skip boot time allocation\n"); > > + cma_reserved =3D true; > > + break; > > + } > > + } > > + > > + if (cma_reserved) > > + break; >=20 > It's a valid problem, and I like to see it fixed. But I wonder if it woul= d be better > to introduce a new helper bool hugetlb_cma_enabled()? And move both > IS_ENABLED(CONFIG_CMA) > and hugetlb_cma[nid] checks there? Yep. that would be more readable. >=20 > Thank you! Thanks Barry