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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 25B8AC2BA19 for ; Mon, 13 Apr 2020 13:34:50 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D6FED2073E for ; Mon, 13 Apr 2020 13:34:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="dgqpBD1o" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6FED2073E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=uzai0Y4oIAPPBWJ7HvFvIHuR5iftuSDN7p65fLjiTbg=; b=dgqpBD1oIFaMH4 3Q+SKnuPqj7A/UXhFI9xur+v/OdTfftB34iuYAAQYPeAmCDgEO8AYdnGu32NvKWDoFROBFgqmGKkn j6rJubeHUl68BfXxCIEqlAibofxJHotuCLP1jSSZspo0MCdJD88q5jdlObYbJSOnv6WKr5LACASVR NQLfYEQXmHKa4RUQS5Cq/khMaOFKfBloilOUnh588sTEeEjHEtg0qH5fQtHzdiBA7Dqv+OV0+UFUu oJcWEINRvtFDCHUfneKxiuhrN5lvSW111yugc7yVakJxJASOKtQE9rYMzECnjZxR1/QsptZ3EdZwa NF7QUkIeFZ1z1zgXSvpQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jNzEc-0003wO-VZ; Mon, 13 Apr 2020 13:34:46 +0000 Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jNzEa-0003wD-Ft; Mon, 13 Apr 2020 13:34:44 +0000 Date: Mon, 13 Apr 2020 06:34:44 -0700 From: Matthew Wilcox To: Nicholas Piggin Subject: Re: [PATCH v2 1/4] mm/vmalloc: fix vmalloc_to_page for huge vmap mappings Message-ID: <20200413133444.GM21484@bombadil.infradead.org> References: <20200413125303.423864-1-npiggin@gmail.com> <20200413125303.423864-2-npiggin@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200413125303.423864-2-npiggin@gmail.com> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, "H. Peter Anvin" , Will Deacon , x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar , Borislav Petkov , Catalin Marinas , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Apr 13, 2020 at 10:53:00PM +1000, Nicholas Piggin wrote: > vmalloc_to_page returns NULL for addresses mapped by larger pages[*]. > Whether or not a vmap is huge depends on the architecture details, > alignments, boot options, etc., which the caller can not be expected > to know. Therefore HUGE_VMAP is a regression for vmalloc_to_page. > > This change teaches vmalloc_to_page about larger pages, and returns > the struct page that corresponds to the offset within the large page. > This makes the API agnostic to mapping implementation details. I'm trying to get us away from returning tail pages from various functions. How much of a pain would it be to return the head page instead of the tail page? Obviously the implementation gets simpler, but can the callers cope? I've been focusing on the page cache, so I haven't been looking at the vmalloc side of things at all. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel