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Shutemov" , , Michal Hocko , Mike Kravetz , Shuah Khan , Muchun Song , Vlastimil Babka , Matthew Wilcox Subject: Re: [PATCH] mm/up: combine put_compound_head() and unpin_user_page() Message-ID: <20201209210332.GW552508@nvidia.com> References: <0-v1-6730d4ee0d32+40e6-gup_combine_put_jgg@nvidia.com> <16128311-9874-dcd4-c641-c68b34c9d634@nvidia.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <16128311-9874-dcd4-c641-c68b34c9d634@nvidia.com> X-ClientProxiedBy: MN2PR04CA0015.namprd04.prod.outlook.com (2603:10b6:208:d4::28) To DM6PR12MB3834.namprd12.prod.outlook.com (2603:10b6:5:14a::12) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from mlx.ziepe.ca (142.162.115.133) by MN2PR04CA0015.namprd04.prod.outlook.com (2603:10b6:208:d4::28) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3654.12 via Frontend Transport; Wed, 9 Dec 2020 21:03:33 +0000 Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kn6cW-008OWG-I0; Wed, 09 Dec 2020 17:03:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1607547818; bh=rc+CwgZOH6EelmjNGA5qY8iOWzJ9DtPiB7oBS9+BNIA=; h=ARC-Seal:ARC-Message-Signature:ARC-Authentication-Results:Date: From:To:CC:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:X-ClientProxiedBy:MIME-Version: X-MS-Exchange-MessageSentRepresentingType; b=kzj2+6uRcy2sBdLLJaleOerBK3GXNY+vdNfOyeuUJPQUcKUZcoQzkXx094oINA5C9 uIFqfzTackkchIrArCGnPt6VhRy6lUF3xB+jMuQdudgJ9bq45rVEZ8tLFspYGBF0JA 1qiTnmrPGNSFE/svnawgzvn5Y+ZwF433lYFENnWCI7kI7Iki4BuvZoORHysMGhXrG+ APQtHlZDiXOoi/BM/nBm1xnR40s6ShqR92KXswDrcHR95Eng0as6gjwQpgbp3+DWmL Mfjb1ngjSlgu6lN+xoWvfbe4EUTEB53EeSseWvDKIYI72uz0Rcaq+iqsdjTHTYcQKN QavPHg+LQMfwQ== 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 Wed, Dec 09, 2020 at 12:57:38PM -0800, John Hubbard wrote: > > diff --git a/mm/gup.c b/mm/gup.c > > index 98eb8e6d2609c3..7b33b7d4b324d7 100644 > > +++ b/mm/gup.c > > @@ -123,6 +123,28 @@ static __maybe_unused struct page *try_grab_compound_head(struct page *page, > > return NULL; > > } > > +static void put_compound_head(struct page *page, int refs, unsigned int flags) > > +{ > > It might be nice to rename "page" to "head", here. > > While reading this I toyed with the idea of having this at the top: > > VM_BUG_ON_PAGE(compound_head(page) != page, page); > > ...but it's overkill in a static function with pretty clear call sites. So I > think it's just right as-is. Matt's folio patches would take are of this, when that is available all this becomes a lot better. Thanks, Jason