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 7382EC71136 for ; Thu, 19 Jun 2025 05:44:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 15ED26B0088; Thu, 19 Jun 2025 01:44:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 135676B0089; Thu, 19 Jun 2025 01:44:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 072786B008A; Thu, 19 Jun 2025 01:44:10 -0400 (EDT) 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 EB1926B0088 for ; Thu, 19 Jun 2025 01:44:09 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 96751A381E for ; Thu, 19 Jun 2025 05:44:09 +0000 (UTC) X-FDA: 83571059418.20.A7D2D32 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf10.hostedemail.com (Postfix) with ESMTP id E24E7C0006 for ; Thu, 19 Jun 2025 05:44:07 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=HO445R6+; spf=pass (imf10.hostedemail.com: domain of rppt@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=rppt@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=1750311847; 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=CK1n9z76ZSwHPRnwvdajkQuzJKJmvffT/21tiH1gzas=; b=cKrDjdJMRzYx8C/iwcQ0GfAdEeK9Qo5d60ld+ahMop21lnS9bQgIn70YYwLN4O+k+byc3W H9GlciTDsrPpOnitJrvp4tnh3B3upMK5Rc3OezefLbMtCcAAw1P0uYvHM/c38Td6VKc6El 8oljFPgs0G82YjXRsHNvqjrJ3/Fdp/k= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=HO445R6+; spf=pass (imf10.hostedemail.com: domain of rppt@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1750311847; a=rsa-sha256; cv=none; b=1Ro3ARDt7BbF5JTS5CSGm5skfhWX3db3E8JJ8EiIOIgUK3pLKl20mMd/Bz/rAhu25WKaTe 3ao3IJcvDjyLfUesap3uLMeRrL8HK4lEM2xpYNuPTijPtAwaDfrtZ9tTOQFUH2wHuCqxdP KhTxlYkIZUcPcgrHHwJjZbPlEcxySWI= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 25DF2A52BCC; Thu, 19 Jun 2025 05:44:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75664C4CEEA; Thu, 19 Jun 2025 05:43:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750311846; bh=52uw0NQcf5nihxhmjL59nvgPCruxZJbKveF+vLTbT9g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HO445R6+OAGiKmC8TLlHe/8nQdfhSr1pmEEVz6I5Pma5vcPbLfTtYBr+KSm8F5+W0 760Ear1g0uCvzzIVZlh0PT60BOr/fgbZOJpj9QQaebMZyAguTGmREJMvLWwOl1bIlX x+Z3/3s9QyPRnMSmL+qjtd9QwNTHKcTqXHfDzvI48pHX3ZJwlad8srJSdrH00XUAMA XvvmQsUZKlVAP8zTU7pUo9TRw2805kOM+rvlKJXBvuad2IoIM7o+ogSTw1cVPeOmsY l6abUyFPH5lkB5zXbIbt9w0NqgA1R+6fsEXpCFzS+OSShF4M1ZyCukx9OHKgDejTSL wL5r16cLytZMA== Date: Thu, 19 Jun 2025 08:43:55 +0300 From: Mike Rapoport To: Hao Ge Cc: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Richard Henderson , Matt Turner , Dennis Zhou , Tejun Heo , Christoph Lameter , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Kent Overstreet , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-s390@vger.kernel.org, Hao Ge Subject: Re: [PATCH v6] mm/percpu: Conditionally define _shared_alloc_tag via CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU Message-ID: References: <20250618015809.1235761-1-hao.ge@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250618015809.1235761-1-hao.ge@linux.dev> X-Rspamd-Server: rspam11 X-Rspam-User: X-Rspamd-Queue-Id: E24E7C0006 X-Stat-Signature: 4k17aqz7ahmmwpzceki3j3bf5nbfj5cq X-HE-Tag: 1750311847-346507 X-HE-Meta: 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 RNjVSxZA c8EG06Rwo5cNNnKB+bWqSS9noMdJTrU7/TlrkHuYHgkmBooeYzi/4EjIMobi21LBDx2O7c7ORM48OyzXxz/SXIpZkI158gEo9LPiwetHtm5e9oI+dmet66k1eFYd2nO/HbdJCBUJ8A9Si/FymWtBnxKKj9qgGKkpwtI1r0+dE52uoe8g0dSLvs16PFszgdeoM2GSVMZhKeGkK/aL6pJhBP1HKDyUjiAkNHytvx6WHyiHhdqNIAt8aXu7TSxxKxPOmkXnv+yApp8Ik9gE/3o/5E2mMxTyVNAFpk6l3e0bhtorqLaaRHPeoker/0qIQXeBTGQun7B+SOX2Sv1YmYXkKwbBYHToR3hqfAwJ12cuZgS+4BfVkHRzACDrK2Q== 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 Wed, Jun 18, 2025 at 09:58:09AM +0800, Hao Ge wrote: > From: Hao Ge > > Recently discovered this entry while checking kallsyms on ARM64: > ffff800083e509c0 D _shared_alloc_tag > > If ARCH_NEEDS_WEAK_PER_CPU is not defined(it is only defined for > s390 and alpha architectures), there's no need to statically define > the percpu variable _shared_alloc_tag. > > Therefore, we need to implement isolation for this purpose. > > When building the core kernel code for s390 or alpha architectures, > ARCH_NEEDS_WEAK_PER_CPU remains undefined (as it is gated > by #if defined(MODULE)). However, when building modules for these > architectures, the macro is explicitly defined. > > Therefore, we remove all instances of ARCH_NEEDS_WEAK_PER_CPU from > the code and introduced CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU to > replace the relevant logic. We can now conditionally define the perpcu > variable _shared_alloc_tag based on CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU. > This allows architectures (such as s390/alpha) that require weak > definitions for percpu variables in modules to include the definition, > while others can omit it via compile-time exclusion. > > Suggested-by: Suren Baghdasaryan > Acked-by: Alexander Gordeev # s390 > Signed-off-by: Hao Ge Acked-by: Mike Rapoport (Microsoft) -- Sincerely yours, Mike.