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 39E63C87FD2 for ; Mon, 11 Aug 2025 13:38:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C26178E0056; Mon, 11 Aug 2025 09:38:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BD6B78E0045; Mon, 11 Aug 2025 09:38:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B136B8E0056; Mon, 11 Aug 2025 09:38:31 -0400 (EDT) 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 A0C508E0045 for ; Mon, 11 Aug 2025 09:38:31 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 407DB1A01A2 for ; Mon, 11 Aug 2025 13:38:31 +0000 (UTC) X-FDA: 83764581222.08.A53C20E Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf27.hostedemail.com (Postfix) with ESMTP id B282340006 for ; Mon, 11 Aug 2025 13:38:29 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ZuYO1pyf; spf=pass (imf27.hostedemail.com: domain of a.hindborg@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=a.hindborg@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1754919509; 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=bOfZRdM/qqYj6GeyhKBjq7vdH2qd/Dbp7Ah9gAR00ZI=; b=ZUdX/DsyNQ1PAeMz+xgzlVEXnU/eqbtfOv+iuSABQJtojfDZPSJsQA4KYMOvuDEnrLvAT1 gsvlShUgApQouIPZeBVZa5vvJXlO7RLT/zihLzlXSHF7qFfyPLmCvHnmaomEnYyBsVrj/4 gGQD2r/cFUai9V2NvEwYskQEurLfE7g= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ZuYO1pyf; spf=pass (imf27.hostedemail.com: domain of a.hindborg@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=a.hindborg@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1754919509; a=rsa-sha256; cv=none; b=crEIPok0sdXjGh3P9VvHDYn2f4XGCYVrLyyJ43BSPIhN+W57sLC7Il+6amMBLN8PsQky3O d0w54SU/ldyPtMi/VI8l/ByGT4daMra17FDsMxFTMG8DTV/I1QgZJ1gsCcDhsSWw26rqD4 59z1PMZ3nUY5cW0auwF9jaWkqqlDr6U= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 18456A56E96; Mon, 11 Aug 2025 13:38:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8109EC4CEED; Mon, 11 Aug 2025 13:38:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754919508; bh=bOfZRdM/qqYj6GeyhKBjq7vdH2qd/Dbp7Ah9gAR00ZI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=ZuYO1pyfJ9AQu5ponOsLQyI4lrsHCY5zViVB2CocdX9e7rbPaqw60Orwg/6+0Yq/C +vNz4IbebOt4JZHXP1AwcVN/ZljhPiLEM2gqB4bJgVNYvgqKPhTfNsoWlsONpjWwdS T0+gWW8CDoSo+qD5OSE7NbuOc3SXdnBQrOoZd92mCxrCaYmjBSffvVydtJaIgt/fYD pwD24D76iZ+XXUX4sE6g2IDBZxVGoT8ml9SptKfceQpzZ8YX4rk+qSdPgmuYzzawAt Eji1kTsjokpo641VRi8RT7J0tnTj4QFdXNWiCLgUPcNzC5ATkj1wt2Is/7a2ABdckj cyzuHr+mkEOaw== From: Andreas Hindborg To: Alice Ryhl , Lorenzo Stoakes , "Liam R. Howlett" , Andrew Morton , Danilo Krummrich , Matthew Wilcox , Tamir Duberstein , Miguel Ojeda Cc: Boqun Feng , Gary Guo , =?utf-8?Q?Bj=C3=B6rn?= Roy Baron , Benno Lossin , Trevor Gross , linux-mm@kvack.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Alice Ryhl Subject: Re: [PATCH v2 0/2] Take ARCH_KMALLOC_MINALIGN into account for build-time XArray check In-Reply-To: <20250811-align-min-allocator-v2-0-3386cc94f4fc@google.com> References: <20250811-align-min-allocator-v2-0-3386cc94f4fc@google.com> Date: Mon, 11 Aug 2025 15:38:20 +0200 Message-ID: <87ldnqf06r.fsf@t14s.mail-host-address-is-not-set> MIME-Version: 1.0 Content-Type: text/plain X-Stat-Signature: bre151sh7j7dq4oxdeew3a6mnq5hejj7 X-Rspam-User: X-Rspamd-Queue-Id: B282340006 X-Rspamd-Server: rspam01 X-HE-Tag: 1754919509-827563 X-HE-Meta: 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 t5eBdjYi cFdRwQeNOCw9Qyvi2hPGj46mthjP66lcPuwKdX0g0cKy/Sfkd+94Y+vJfczpkmcHYfrosE3Jsg3G8EN88PSwfMB/9VK9WjDtrGPXt1PQlPicn2QxCS5ntyZfddXiExZqYaGWfQKYGqXcj0+F0v8PDqtrvz6Pae5DXuz9a6fEHmtt6/vAmCsGp96JdCLhlcn82YsViKavHpTuPlH1rKpYgF73Uj4aicrMxWiuTJG9uxUoh9SNDp22JSQPGlMt4rJWI7B1tr3jHL9I0waJ5HI/zouOlExj+Nk8rwDMmpbzpJ5JQP90Npc0AhXrG4UwzXQbhRR/NllGTwf/CETAbOkcF0TOtTGu42OUv+ORvY6+akR46JikaCJik5/rY6ZgDUPfTChrr66+bZkJgrvyss4K4BzCykQ== 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: "Alice Ryhl" writes: > The Rust bindings for XArray include a build-time check to ensure that > you can only use the XArray with pointers that are 4-byte aligned. > Because of that, there is currently a build failure if you attempt to > create an XArray> where T is a 1-byte or 2-byte aligned type. > However, this error is incorrect as KBox<_> is guaranteed to be a > pointer that comes from kmalloc, and kmalloc always produces pointers > that are at least 4-byte aligned. > > To fix this, we augment the compile-time logic that computes the > alignment of KBox<_> to take the minimum alignment of its allocator into > account. > > Intended to land through alloc-next under the RUST [ALLOC] entry. > > Signed-off-by: Alice Ryhl Reviewed-by: Andreas Hindborg Best regards, Andreas Hindborg