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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79452C48260 for ; Fri, 16 Feb 2024 09:31:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E43FF8D0006; Fri, 16 Feb 2024 04:31:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DCCCE8D0001; Fri, 16 Feb 2024 04:31:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C46E08D0006; Fri, 16 Feb 2024 04:31:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id AE4818D0001 for ; Fri, 16 Feb 2024 04:31:35 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 2E8BAA0378 for ; Fri, 16 Feb 2024 09:31:35 +0000 (UTC) X-FDA: 81797149350.09.26B930E Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf14.hostedemail.com (Postfix) with ESMTP id 67A6A10001E for ; Fri, 16 Feb 2024 09:31:31 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=PABjN2KR; dmarc=none; spf=none (imf14.hostedemail.com: domain of BATV+0975fe26c86320a24587+7481+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+0975fe26c86320a24587+7481+infradead.org+hch@bombadil.srs.infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1708075893; 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=Hicma0LaStbdWVQEFGL/bnJpIAjnQ4a5jIR0FW4imjs=; b=7v154+D5NIP/CH0LZnBszvOcHIKnLC80bLimlZ2sb9WAjQ9u3VwONFLqMPFtRkhxz5pHCA nRZqR9kA4ncoqxd/EKXt5hUV81GlH/WvDej7SEDuOiXJ8aMvoWc3RhRcgZU2FjX1uF5Gdf V8G1Gtv91v45uaaAN6f2LTHJxG27adQ= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=PABjN2KR; dmarc=none; spf=none (imf14.hostedemail.com: domain of BATV+0975fe26c86320a24587+7481+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+0975fe26c86320a24587+7481+infradead.org+hch@bombadil.srs.infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1708075893; a=rsa-sha256; cv=none; b=ygIjTPjqbkb+wkAZfruToMK6+wYUGGveuvvx0fK7k7bwfJr4s/Xd7amTceWNnZtLaf1cK6 Xk1bkXDJeWZyWl16oeH6vX7o1cC8h2TPVtECws1SPHXEPoCvce517An+vU5UZpY42b/HUQ 3joZLs2+Ppz4DbkZgKFcQTnaaKVL2fI= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Hicma0LaStbdWVQEFGL/bnJpIAjnQ4a5jIR0FW4imjs=; b=PABjN2KRs75C+Vfx0CBHiMH3+a IMl809OdPIdKP2dwV4WtmyhKmonCv6z3c+yNh1PmN6xGqPGKwdMbqpSMR8WccgpTboV23sgDBtPN6 DbdMgAesHefcqhd0P324IXLgllyMtCH9Ziiy8dKsPNimINKks7E+SlaWSDO1RDWoE87KGN5uI0RTZ vWbukqoAplu9QZVoW8LOYnr/hh5gDDrij9RvwjB7i1adoKgsDN1/DWAQ/M/qwof95bm68zHecUK2y rXUc6tHxYBYprKiUL8AytPLnX23ErtT5sGWvhMsi8oSk9Bn0rqpY84HENFuL4bQzGXiHAiZItc7e4 R2OeoUGw==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rauYu-00000001jzU-2iun; Fri, 16 Feb 2024 09:31:16 +0000 Date: Fri, 16 Feb 2024 01:31:16 -0800 From: Christoph Hellwig To: Alexei Starovoitov Cc: Christoph Hellwig , Linus Torvalds , bpf , Daniel Borkmann , Andrii Nakryiko , Kumar Kartikeya Dwivedi , Eddy Z , Tejun Heo , Barret Rhoden , Johannes Weiner , Lorenzo Stoakes , Andrew Morton , Uladzislau Rezki , linux-mm , Kernel Team Subject: Re: [PATCH v2 bpf-next 04/20] mm: Expose vmap_pages_range() to the rest of the kernel. Message-ID: References: <20240209040608.98927-1-alexei.starovoitov@gmail.com> <20240209040608.98927-5-alexei.starovoitov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Queue-Id: 67A6A10001E X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: xobkc66pwaccqh3g3nd7keqi4yify1dd X-HE-Tag: 1708075891-351754 X-HE-Meta: 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 LM2b3QHh 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 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: List-Subscribe: List-Unsubscribe: On Thu, Feb 15, 2024 at 12:50:55PM -0800, Alexei Starovoitov wrote: > So, since apply_to_page_range() is available to the kernel > (xen, gpu, kasan, etc) then I see no reason why > vmap_pages_range() shouldn't be available as well, since: In case it wasn't clear before: apply_to_page_range is a bad API to be exported. We've been working on removing it but it stalled. Exposing something that allows a module to change arbitrary page table bits is not a good idea. Please take a step back and think of how to expose a vmalloc like allocation that grows only when used as a proper abstraction. I could actually think of various other uses for it.