From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F1FF1A681B; Tue, 2 Jun 2026 04:41:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780375284; cv=none; b=rF4pI20cmK2VmC2f4nFMvqYtQ5HIqRyqSOZb3RvgaZ8WUn/zYlO4f+eJkyk7PiIyqwtIQVxn8rysgQBdjBqDWUhxQMittNBOy/lUY4BfteTwRdntnyXp5WdgKz7fhMamloWDv+8N3/7fFEijI39D4MM54HoN1UedgWE5Sev7+Qc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780375284; c=relaxed/simple; bh=XIPqheZyfxMHX/MdGE3lK6sIyCyahrpLJ6uAqRJ/k2s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=M5XV2cMM2H7XibeVGHm00pHmgPBrcLjAnoUTgzDbrNN/TmApC1JfAAidqvTjrTtqALVHxAJQjyBabogD+F/j3eRvagMULGOrvDjsgDFRrhRWl86r+dHUkG5BDazjMOQNTFau7yK+igvH5ktvOzSN3dmGCHP6HmA79a9dnjztbMg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fVVCf76D; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fVVCf76D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 227081F00893; Tue, 2 Jun 2026 04:41:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780375282; bh=5iTAXR5bbzIxHxlJbNzCQ0CqrWCPbLprw+Rivi0AdWo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=fVVCf76Dx7vvRtOjppgGy1UPYStuohI+uy9DWtC+LjMgaEMLbdvFewnh94OAL+CM2 pCOKO3Nnfhfp4QVVVFHJ7pGlC0pcRPQSBoK+8qI+lMS8vE1L9za9TMoAEhapGCyg9z oSOX6UXAQ0qI8lZdcWzGnsDHIE/3SlXVTvbbZnLLGgJsb+q9w7gAY3CfUe/oXsaq3F IKCnC0jDUA164OuR9mISVXoVORX5ONpBDuDwwi+L6+sBtk7/0MupCBLirVc0R3mesL YLqI48YwygT3VSDU6XtM8NAwITqzxDNVTMAKliil4c0o+GhGmZTerIkNtW6sdsl3Fh evYO5/MHJ+rmg== Date: Tue, 2 Jun 2026 06:41:14 +0200 From: "Oscar Salvador (SUSE)" To: Muchun Song Cc: Andrew Morton , David Hildenbrand , Catalin Marinas , Will Deacon , Palmer Dabbelt , Paul Walmsley , Huacai Chen , Andreas Larsson , "David S. Miller" , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, loongarch@lists.linux.dev, sparclinux@vger.kernel.org, Alexandre Ghiti , Albert Ou , WANG Xuerui , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Subject: Re: [PATCH v3 1/5] mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd() Message-ID: References: <20260601084845.3792171-1-songmuchun@bytedance.com> <20260601084845.3792171-2-songmuchun@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260601084845.3792171-2-songmuchun@bytedance.com> On Mon, Jun 01, 2026 at 04:48:40PM +0800, Muchun Song wrote: > The two weak functions are currently no-ops on every architecture, > forcing each platform that needs them to duplicate the same handful > of lines. Provide a generic implementation: > > - vmemmap_set_pmd() simply sets a huge PMD with PAGE_KERNEL protection. > > - vmemmap_check_pmd() verifies that the PMD is present and leaf, > then calls the existing vmemmap_verify() helper. > > Architectures that need special handling can continue to override the > weak symbols; everyone else gets the standard version for free. > > Signed-off-by: Muchun Song Acked-by: Oscar Salvador (SUSE) -- Oscar Salvador SUSE Labs