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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9A72DD0EE00 for ; Tue, 25 Nov 2025 17:21:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CBED56B0096; Tue, 25 Nov 2025 12:21:31 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C96BA6B00A2; Tue, 25 Nov 2025 12:21:31 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BD3A36B00A4; Tue, 25 Nov 2025 12:21:31 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id AD19C6B0096 for ; Tue, 25 Nov 2025 12:21:31 -0500 (EST) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 707E61308A8 for ; Tue, 25 Nov 2025 17:21:31 +0000 (UTC) X-FDA: 84149795982.02.8B356D1 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf08.hostedemail.com (Postfix) with ESMTP id 6C998160014 for ; Tue, 25 Nov 2025 17:21:29 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=f0+AP+ps; spf=pass (imf08.hostedemail.com: domain of akpm@linux-foundation.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1764091289; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=nFsKSOAAt+BJ2HW3Q+CmoZoy3mVn+ELlSFmfSNw3rCk=; b=DZ0pdPk1EqaxuKA+hzic2f3aCOciDQLuxfx6ziGRBY0F+M6YhzF0pAauKzVx7oVuKgE93A dlZAqZX9QCpjORinx7omRcbUhnVN/EMl5aZWudk15fwNemMY9WQnWTWd3feckluOxstxah uerxOI2xPP3h9YCJK06CXJV77gpj//M= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=f0+AP+ps; spf=pass (imf08.hostedemail.com: domain of akpm@linux-foundation.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1764091289; a=rsa-sha256; cv=none; b=ciiEPkdz7oH8o0f2M7609EsN9QweDLKiDGJ2RgtJc+Jgp3OOOSHROVHDHayCz67gbM1WHO odfIwRB/XDPYuBueSGRY1BFEUvOvafujCvwA+bW69PMDTA8/N/yLduGQhVU01upiTVO5gd kog3mGYEGTyKR4Qj0Gd/OJEFZnDI3VU= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 226CD43FF4; Tue, 25 Nov 2025 17:21:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9F6FC4CEF1; Tue, 25 Nov 2025 17:21:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1764091288; bh=5V9QV7SiBzMU5nx3Mn2uqFLHCyID9A3N1YOoa6yxqY4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=f0+AP+psoLoGzXaq00ep6BDykJP5aOdtZfoQZ4KAyuamvgXUZO/UGmEJZu88bAQIq Ph+B0PjesF0Ac7gLWJ9KCv+Omr0a+hSLWs0rbzhWkIUTz4dhCv1QM8hBT4VZXdt0Tw qAckYaIks0SEUeBlWRsbMccDVtm+g6LfRTNVGc0U= Date: Tue, 25 Nov 2025 09:21:25 -0800 From: Andrew Morton To: Lorenzo Stoakes Cc: Muchun Song , Oscar Salvador , David Hildenbrand , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Axel Rasmussen , Yuanchu Xie , Wei Xu , Peter Xu , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Kees Cook , Matthew Wilcox , Jason Gunthorpe , John Hubbard , Leon Romanovsky , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Xu Xin , Chengming Zhou , Jann Horn , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Pedro Falcato , Shakeel Butt , David Rientjes , Rik van Riel , Harry Yoo , Kemeng Shi , Kairui Song , Nhat Pham , Baoquan He , Chris Li , Johannes Weiner , Qi Zheng , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , Bjorn Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , rust-for-linux@vger.kernel.org Subject: Re: [PATCH v3 0/4] initial work on making VMA flags a bitmap Message-Id: <20251125092125.3e425e05382642ddff2db496@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: 49p5xf9ch6m7su7ah5p1dk54t6y9rxcz X-Rspam-User: X-Rspamd-Queue-Id: 6C998160014 X-Rspamd-Server: rspam09 X-HE-Tag: 1764091289-111180 X-HE-Meta: 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 ld4ZLtVW fTPXZywK0WH0v454VCxVm9RYHhHBeOITnrasWO5e+qxfOBRH7m3YucbHv+FACTvSLVKTDvTkwBYqL7I06J1NbsMLdWtcSQo/Py4cxj1bssl3xlSGvg9u7T3wYw5jDvFXRhOXmEXSkHS3bDJ1KbLC9Cm9YSyHLPRGwn5LK8BFVWvGx1cAdjONoW6RrA9Kuhhxw+am7mwL7deQaUHAFgrP4al4RJ1o2td6fSQt7+Y5bNRHC+HjVflHMsOn56jc2Ne0R8GtMdCnY4AYkFvbmmm9bs94aj5uxa403izcbDHlXnzp6nqmJlNEb6s+4nJUlyG9oayPCIILfFGPnKhTUz4iW/uPHXw== 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 Tue, 25 Nov 2025 10:00:58 +0000 Lorenzo Stoakes wrote: > We are in the rather silly situation that we are running out of VMA flags > as they are currently limited to a system word in size. > > This leads to absurd situations where we limit features to 64-bit > architectures only because we simply do not have the ability to add a flag > for 32-bit ones. > > This is very constraining and leads to hacks or, in the worst case, simply > an inability to implement features we want for entirely arbitrary reasons. > > This also of course gives us something of a Y2K type situation in mm where > we might eventually exhaust all of the VMA flags even on 64-bit systems. > > This series lays the groundwork for getting away from this limitation by > establishing VMA flags as a bitmap whose size we can increase in future > beyond 64 bits if required. All added to mm-unstable, thanks.