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 833F0CEFC24 for ; Tue, 8 Oct 2024 15:22:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 16E636B0095; Tue, 8 Oct 2024 11:22:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 11F406B0096; Tue, 8 Oct 2024 11:22:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F024F6B0098; Tue, 8 Oct 2024 11:22:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id D16FE6B0095 for ; Tue, 8 Oct 2024 11:22:08 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id CEC2BAB634 for ; Tue, 8 Oct 2024 15:22:05 +0000 (UTC) X-FDA: 82650800736.18.ED4B02C Received: from mail-qk1-f174.google.com (mail-qk1-f174.google.com [209.85.222.174]) by imf08.hostedemail.com (Postfix) with ESMTP id AE88F160027 for ; Tue, 8 Oct 2024 15:22:06 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=gourry.net header.s=google header.b=sx2vbUvR; spf=pass (imf08.hostedemail.com: domain of gourry@gourry.net designates 209.85.222.174 as permitted sender) smtp.mailfrom=gourry@gourry.net; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1728400858; 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=XZ67u8RxgzRAwx2Ool9AQUwW74l6Qtl1I/8HA1yVK7o=; b=mvf7WeOH67hFSFENeg9xi43z/fBPxthXS44Byh/3VFIoNXcYnhR39emnB0h6lsuwozT2wv kCIGWPvEoBV37TvDrzPtqzg+ybpnQ3EVr8o2ZIaN3Rq+aLa507T47Lft6vcD7tEnFZcwvD sKGJosdsauH4oic0Ot+vKx4WwYbMWKQ= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=gourry.net header.s=google header.b=sx2vbUvR; spf=pass (imf08.hostedemail.com: domain of gourry@gourry.net designates 209.85.222.174 as permitted sender) smtp.mailfrom=gourry@gourry.net; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1728400858; a=rsa-sha256; cv=none; b=clgrI6aURE5Q78NI6aernapBkj7Z92pU0GPlhrl3hrfAYTErhvrRk04UQXtTUhsOnMOSVw /a+Eu7ZOWVnv0l8toPCbg3XMqiZSB6v2e34OeAUJ0MoZbdO5iPCgkexUGFBCAqjMAGbx9X le4YWbapnVW9pZHRsPbx1yKfaOCJfYk= Received: by mail-qk1-f174.google.com with SMTP id af79cd13be357-7ac83a98e5eso498659485a.0 for ; Tue, 08 Oct 2024 08:22:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1728400926; x=1729005726; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=XZ67u8RxgzRAwx2Ool9AQUwW74l6Qtl1I/8HA1yVK7o=; b=sx2vbUvRiqpeq1OUr+DU20raiYAu5nx72DEM9lMLMqRZG/VtwJCThTRJDbQ5e14mFX r6SNiO4gqttqSGz3wd6EFxI+S69pla9ZIx7q4G5iCi1gDqA/PCMg/lX/bKPcwTUiUOHI hUPEHsekpU1i/aFAetR//fDmt+JZBc4tjG1e7XkLMjnM3AriPxs2OPttWFHrZkjQmWVN fU6lXbmr9l5p2P4kCdOBs9mv53G1PlG4XJ6nFoZJeuW47sGcdcOw4IL3dGdqHl9Bxjz7 5UXN3KLvXQCxqg8hCJS3Ik5yLFfhyPxbV2amZDogfpaT06KfPxWeq7LvRmFztbSh3nUD 3Y+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728400926; x=1729005726; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=XZ67u8RxgzRAwx2Ool9AQUwW74l6Qtl1I/8HA1yVK7o=; b=NJYWw+z/VO9Wt08t53TV6Tb5f7dhQc7fqNrQGP1lJbGw365uGtOxiisIFU7sZna3zs XvJHX0flgb/LL1MfOKoNp6LEtTELETYyCVWZm8kIYeZzt0C8m8OgNxBbNg6x+q6svao2 Y0By6YWnqUBGS8Bhu2POwsXubOKA+W0I8Qql7dzKuOoK47uakKTfOM6p/++1O/lfcRuc Xx0S6sl7NhvYfLJeDUQKPUk/h9wnnMIIYmrItsvuqv3J3l91nCZ0/HeRWjloJdfWops9 XAhqEb9UEWWn8sL2w+kO/jA1w81sQz9hlvEY6H2ce61ixbUKNw/KNrCzz8EindqGs6G1 +F1w== X-Forwarded-Encrypted: i=1; AJvYcCXAkJNrdGAh7dYT6iBVcfnZpxR4QTbQaIk1GnVSwKKy2FqY3gIQq+iw7DiOHZQJZIJK0Af/5j0eZg==@kvack.org X-Gm-Message-State: AOJu0YwpX7eUq3DDciXOn1CcL+nn0tymc91ZfRd0wfs7RhiJbHvRFrWE hCxVNZbrgp4qCj2oxNjik4gTun0qnTMKnYchSGz7POGGOuXVtTV5Ir7HDNCMDI8= X-Google-Smtp-Source: AGHT+IGMO0Tvvi9+VmcOsgILzXspWMlWZQ5WxVaJLr0S8i8w6Q2UsaoDkhwE/bfLc/fA5kw9BP3AeA== X-Received: by 2002:a05:620a:1791:b0:7a9:95f6:e372 with SMTP id af79cd13be357-7afcf03a0e9mr69595385a.2.1728400925668; Tue, 08 Oct 2024 08:22:05 -0700 (PDT) Received: from PC2K9PVX.TheFacebook.com (pool-173-79-56-208.washdc.fios.verizon.net. [173.79.56.208]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7ae7562caf3sm361427285a.36.2024.10.08.08.22.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Oct 2024 08:22:05 -0700 (PDT) Date: Tue, 8 Oct 2024 11:21:55 -0400 From: Gregory Price To: David Hildenbrand Cc: linux-cxl@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, osalvador@suse.de, gregkh@linuxfoundation.org, rafael@kernel.org, akpm@linux-foundation.org, dan.j.williams@intel.com, Jonathan.Cameron@huawei.com, alison.schofield@intel.com, rrichter@amd.com, terry.bowman@amd.com, lenb@kernel.org, dave.jiang@intel.com, ira.weiny@intel.com Subject: Re: [PATCH 1/3] memory: extern memory_block_size_bytes and set_memory_block_size_order Message-ID: References: <20241008044355.4325-1-gourry@gourry.net> <20241008044355.4325-2-gourry@gourry.net> <039e8c87-c5da-4469-b10e-e57dd5662cff@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: AE88F160027 X-Stat-Signature: cib3fk33doaqcqt1dgoztobz5fabnyf7 X-HE-Tag: 1728400926-438023 X-HE-Meta: U2FsdGVkX1+5sFJiHiuieGmCkOmOpIJ8/Jg/sWRWBc56bIA3v/A5Y8SuyDGH0PBx6sU+eP0aZEwSVwjZLctQLXZhEq4ZbIp7J6Q7G/zSf7pH7bHFF45ADP/Z4BAeEH+waxkSgPUAa2QssimJZ/X3s9BfLC1EXSg4bZZ/ozblDMAOt728qvMCwwDI/Gz+zdxChYL0o4F7Sc2/EvqCEpJafSHIjJpFtugaJGA71BWLf2GxV9R0n64dhAozHA8iTC01LBMsfQVx+9pCi5cKzuVnvdWPOtzO0wQ6JQDrdCIZs9rHac4rY8LQKabe3G9iSCRE9uRPixpxlLOHQMOulZzTUHnm6TXYthkW89t/0mdyksSIS19RmnSaeBVXNYdwCucEiKJdycZQtLkHaSVJdHqmzXt1Xf/+npziQSWTIk2YXvKlLlZriXzVz8jRjHoVG4dmSYETieV2DpeKSepxNe3FvzBr5+QYQYF/SYDksJpWwHz/8j8qmyrLoOMtcDJkCM6sViGsLVUzyIUXj3rhybuhGiKFxeqT/h6llpRzJ0bPHxnxFepSxWVmIQvCy2dzhpqa4XFlKeKXfhS4ZRXc77bP08cTO1WDfn5i5kpb4jvRwns4xf4Ow02ycahwWrGceLWFjH0NJg45MArltmuI0Bjjs7P4Z+x9wCngUwragnr2kEayJSEXfo3v8ZC8XEsL2z5vNxe/EoEBrLogqQzxP3RglipLty7VPpI2Wg5HSbgd0989AFZ1sQKJKMyiCTR8Mvcd9Xfd7nN4VJaQLbcWN+MQbFlXxk8E3Cy3L/UV7iTCTlHyR+MO879IQ7h0R35fDkf5x6+MME5fsq0vp24qupjFyXja1336HkSYvtseh++GDCjehshA0uVMnvflHs0ID2l+3d2nEPdjNKYkTEPwwpuCvR3iyj+yWCdIe93cqJYFT+26wofXnTZeoC0EZv6RLR/IuTimDnpO82bQgb88ssR rr+zvJLf 5lJ8zeIpwXfyoenL0gj1z9YoukPmrCIvgXkfUW5XG3VSAVP5SMuOLk9E/UYwVEQChJR7LErdYKS9hD4TKz8FMyFVkCz9TR6AMPKNi/M1f+enU7Q4q4IChP1iM+qy4YmPbqDkoJCAbgbE1z9z/uqruepcpwx583waPCmgMtelpFZYkvaaXSfsEymww7y+xHp9OnTy+5wA6BKt1zPLQ1tV5XDkNbj4TTDloHmc/qvOb/+OpASrDalg1TTAqxxIV2/TKNVKJgjQj7hJRazeIgy4RLzhLp0CD0uABtDVjjb2ImB1/DakTw6kvqsWtCEytJtIr111Z9MQBDrH3Mc9jY/KlpD9g+A== 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, Oct 08, 2024 at 05:02:33PM +0200, David Hildenbrand wrote: > On 08.10.24 16:51, Gregory Price wrote: > > > > +int __weak set_memory_block_size_order(unsigned int order) > > > > +{ > > > > + return -ENODEV; > > > > +} > > > > +EXPORT_SYMBOL_GPL(set_memory_block_size_order); > > > > > > I can understand what you are trying to achieve, but letting arbitrary > > > modules mess with this sounds like a bad idea. > > > > > > > I suppose the alternative is trying to scan the CEDT from inside each > > machine, rather than the ACPI driver? Seems less maintainable. > > > > I don't entirely disagree with your comment. I hummed and hawwed over > > externing this - hence the warning in the x86 machine. > > > > Open to better answers. > > Maybe an interface to add more restrictions on the maximum size might be > better (instead of setting the size/order, you would impose another upper > limit). That is effectively what set_memory_block_size_order is, though. Once blocks are exposed to the allocators, its no longer safe to change the size (in part because it was built assuming it wouldn't change, but I imagine there are other dragons waiting in the shadows to bite me). So this would basically amount to a lock-bit being set in the architecture, beyond which block size can no longer be changed and a big ol' splat can be generated that says "NO TOUCH". > Just imagine having various users of such an interface .. I don't wanna D: > > -- > Cheers, > > David / dhildenb >