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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id e1-20020a056830200100b00661b5e95173sm5879346otp.35.2022.11.09.17.58.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Nov 2022 17:58:30 -0800 (PST) Date: Wed, 9 Nov 2022 17:58:17 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: "Kirill A. Shutemov" cc: Hugh Dickins , Andrew Morton , Matthew Wilcox , David Hildenbrand , Vlastimil Babka , Peter Xu , Yang Shi , John Hubbard , Mike Kravetz , Sidhartha Kumar , Muchun Song , Miaohe Lin , Naoya Horiguchi , Mina Almasry , James Houghton , Zach O'Keefe , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/3] mm,hugetlb: use folio fields in second tail page In-Reply-To: <20221105191321.572bdm67tulpva5k@box> Message-ID: <9de71a55-8f6d-a32e-cd57-f8ab8581e50@google.com> References: <5f52de70-975-e94f-f141-543765736181@google.com> <3818cc9a-9999-d064-d778-9c94c5911e6@google.com> <20221105191321.572bdm67tulpva5k@box> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1668045512; a=rsa-sha256; cv=none; b=Mpcj3fVMUiWfjzYnn6mVOK9y+21vCqdiV8CnOxRMXDUBphPEmPl3cdY4k/MJpD51b4C4gS Xm6sf8iWp5Fzt1LCI7Wl37NdHA5GuzmNXevOkxg/a8TfzEtDMk2l+4iHZlnlWWhPX4S2Dx b6nWdTQMTlVwbVhe74AlTz4g5t6lrPk= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=WgNpeFH3; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf04.hostedemail.com: domain of hughd@google.com designates 209.85.160.47 as permitted sender) smtp.mailfrom=hughd@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1668045512; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=U3+h3Jg4UrytHO9CCFQac05mLjppk7PsqbWzF0gjR58=; b=uM23qz0zsanT7p7xvkHElDDqxlD3YW62jhpbi65IuZ7ShTTZSKx6iiMJjtcp6cCHIivm4i t3Rp3e03u2szjKm3WvmXGdnpUwUE4QjSxkwg7BdoA3ZTzElABp8A3T5+TiUTufFCm/XDl8 Kz6ioPoPRAaeNW/JVejnqwMtV/H7g6A= X-Rspamd-Queue-Id: 5E92740003 Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=WgNpeFH3; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf04.hostedemail.com: domain of hughd@google.com designates 209.85.160.47 as permitted sender) smtp.mailfrom=hughd@google.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Stat-Signature: zjqud9u4sowq7xdiz5g7kahoakey9ad1 X-HE-Tag: 1668045512-674210 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 Sat, 5 Nov 2022, Kirill A. Shutemov wrote: > On Wed, Nov 02, 2022 at 06:48:45PM -0700, Hugh Dickins wrote: > > @@ -260,13 +267,16 @@ struct page { > > * to find how many references there are to this folio. > > * @memcg_data: Memory Control Group data. > > * @_flags_1: For large folios, additional page flags. > > - * @__head: Points to the folio. Do not use. > > + * @_head_1: Points to the folio. Do not use. > > * @_folio_dtor: Which destructor to use for this folio. > > * @_folio_order: Do not use directly, call folio_order(). > > * @_total_mapcount: Do not use directly, call folio_entire_mapcount(). > > * @_pincount: Do not use directly, call folio_maybe_dma_pinned(). > > * @_folio_nr_pages: Do not use directly, call folio_nr_pages(). > > - * @_private_1: Do not use directly, call folio_get_private_1(). > > Looks like it misses > > + * @_flags_2: For large folios, additional page flags. > + * @_head_2: Points to the folio. Do not use. > > to match the first tail page documentation. > > Otherwise the patch looks good to me: > > Acked-by: Kirill A. Shutemov Many thanks for all your encouragement and reviews, Kirill. Okay, I've added a couple of lines on those fields; but did not want to recommend the _flags_2 field for use (by the time we run out in _flags_1, I hope all this will be gone or look different). I'm sending an incremental fix, once I've responded to Sidhartha. Hugh