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=-23.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 E1489C433DB for ; Mon, 1 Feb 2021 21:31:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 92D0E64DDB for ; Mon, 1 Feb 2021 21:31:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 92D0E64DDB Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2924C6B0005; Mon, 1 Feb 2021 16:31:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 243146B0006; Mon, 1 Feb 2021 16:31:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 159C26B006E; Mon, 1 Feb 2021 16:31:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0005.hostedemail.com [216.40.44.5]) by kanga.kvack.org (Postfix) with ESMTP id F3B6A6B0005 for ; Mon, 1 Feb 2021 16:31:56 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id BE1308249980 for ; Mon, 1 Feb 2021 21:31:56 +0000 (UTC) X-FDA: 77770996632.23.shock98_620d251275c5 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id A772237608 for ; Mon, 1 Feb 2021 21:31:56 +0000 (UTC) X-HE-Tag: shock98_620d251275c5 X-Filterd-Recvd-Size: 4868 Received: from mail-pf1-f172.google.com (mail-pf1-f172.google.com [209.85.210.172]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Mon, 1 Feb 2021 21:31:56 +0000 (UTC) Received: by mail-pf1-f172.google.com with SMTP id b145so5722752pfb.4 for ; Mon, 01 Feb 2021 13:31:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=Db9wzFspMKv2GZMUp3j8AjHx8VTQiM19HjB9nvBRaLU=; b=lt/Aa4uQ8poWCQc2Nz7076yxPFNeImt5BPs9gtS0QSIHvFmRQ+ed8VhKEkhOTsh1T9 S3kmC7fgGI3pJK69d9qfuvaiHZmP1dCydmj3yEQwiP5yjC82Gu5DmVTuX+yu15nisv4I FyJnk6sVTW9MfHesCSPTwEGKfvyyHv6Vb1FFzBpJSxP2hoexC6K+Q59k/sYzfKqJV8et AxZUztLba78aHKyFyzQflBEkQUqCdWxcRP7wZ/ir5vBdJ21nDFuq0pQEiEp3OfCR5iWV I6ZO2EifAn+M9KgJikMJBGY1muYYTjOfwq72WyTGwYsvyoaa927iD8KkghKAd530GkH1 pOtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=Db9wzFspMKv2GZMUp3j8AjHx8VTQiM19HjB9nvBRaLU=; b=rtzP4wNPraSRIsmO4bEKg/PrrmUDBewXNBx334QEGrU1CG5SCCNUsq/vG4yxlmRad0 QdZXQdo1KAn1iwT74L28TbvZFWZFXHIa1HK12ygdM0Tv/2wzkuHxzR4pCLmPgub0cEWW kRs6uG+KaSj1usBI45gDfMJUF8prxnko1ALtAVCMQ7xkfgUZhTPWx8YKK8oqASY3Gvz6 P1dG3LMJ4mM4QQUaok4uQ3BI9VSnCd6zDa2bdZ0VzcP3DV1/qJdXxwThZegfR4+pnseW 79px66NvhcyFmVqqWiLhq28NYGHkyAF39DehVew86GMm//I61pp6wUFtJ1Dj9gMNkJHm b9Pw== X-Gm-Message-State: AOAM530/sgBfu6mtMFzSq+3h/ypMoAIKZbwJJZDUInaI4koGkY3/mwh3 USgT4YuyZXUsp1l0+mMTVa2xPw== X-Google-Smtp-Source: ABdhPJwDtVQ/1GoQJP95AYbpB6XU4+QBaoUMIhtqYBJo9OpVXWoOnvzaXeQuY3/MRAGVyxXX1kPZBA== X-Received: by 2002:a62:64c9:0:b029:1b9:6b48:7901 with SMTP id y192-20020a6264c90000b02901b96b487901mr18528679pfb.0.1612215115053; Mon, 01 Feb 2021 13:31:55 -0800 (PST) Received: from [2620:15c:17:3:4a0f:cfff:fe51:6667] ([2620:15c:17:3:4a0f:cfff:fe51:6667]) by smtp.gmail.com with ESMTPSA id b27sm19920266pgb.82.2021.02.01.13.31.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Feb 2021 13:31:54 -0800 (PST) Date: Mon, 1 Feb 2021 13:31:53 -0800 (PST) From: David Rientjes To: Miaohe Lin cc: akpm@linux-foundation.org, mike.kravetz@oracle.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] hugetlbfs: show pagesize in unit of GB if possible In-Reply-To: <24ab70d6-1d23-d118-f1e7-473f01615dcc@huawei.com> Message-ID: References: <20210130090339.4378-1-linmiaohe@huawei.com> <24ab70d6-1d23-d118-f1e7-473f01615dcc@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 1 Feb 2021, Miaohe Lin wrote: > >> Hugepage size in unit of GB is supported. We could show pagesize in unit of > >> GB to make it more friendly to read. Also rework the calculation code of > >> page size unit to make it more readable. > >> > >> Signed-off-by: Miaohe Lin > >> --- > >> fs/hugetlbfs/inode.c | 12 ++++++++---- > >> 1 file changed, 8 insertions(+), 4 deletions(-) > >> > >> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > >> index 3a08fbae3b53..40a9795f250a 100644 > >> --- a/fs/hugetlbfs/inode.c > >> +++ b/fs/hugetlbfs/inode.c > >> @@ -1014,11 +1014,15 @@ static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root) > >> if (sbinfo->max_inodes != -1) > >> seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes); > >> > >> - hpage_size /= 1024; > >> - mod = 'K'; > >> - if (hpage_size >= 1024) { > >> - hpage_size /= 1024; > >> + if (hpage_size >= SZ_1G) { > >> + hpage_size /= SZ_1G; > >> + mod = 'G'; > >> + } else if (hpage_size >= SZ_1M) { > >> + hpage_size /= SZ_1M; > >> mod = 'M'; > >> + } else { > >> + hpage_size /= SZ_1K; > >> + mod = 'K'; > >> } > >> seq_printf(m, ",pagesize=%lu%c", hpage_size, mod); > >> if (spool) { > > > > NACK, this can break existing userspace parsing. > > . > > > > I see. I should take care of this. Many thanks. > Thanks. It's an important point to emphasize because it shows how important user-facing interfaces are. Once the hugetlbfs mount options are printed in the way they are, it becomes very difficult to change them because there can be userspace in the wild that would break as a result. This is why it's crucial to be very careful when specifying user-facing interfaces the first time so they are extensible.