From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D0DDE134CD0; Tue, 16 Apr 2024 18:19:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713291552; cv=none; b=IDof4kg6bRLphZVGTa90U5oL3yYJQYIXhtnDmfY8qmIhIOvHv2c4e8BIpm9vO/W4SsMudFZx7F02uNJpwcGfn76hfHv49ufSBhZtJeiVHrucb1yo+lMnqQCyNZfQkRSKQ3Da95iLy/FunRYLcjqZBQ7vwK/eIk1BJcutYCiOf3Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713291552; c=relaxed/simple; bh=OSFyHt08QH9EQT0OH6l2mjM6TDXgg4K1qPiqN9EnzTQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ktixbaK0mtmPhVBhY7SP8XepjcNYspSFTkHw+r+/R6nmHSy6B7QFl/+ZqGDvRr6tjj51VOeuWxk0Rbc3zoi9o1LrzrnQWcK1sEVzi/cMiJX3Ib68krsfhwHycXTC85KC/SIksYCUz0RVKXxexpexeiHqEfDr91dMkakuHnfF/4o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TJFISS3f; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TJFISS3f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E1C2C113CE; Tue, 16 Apr 2024 18:19:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713291552; bh=OSFyHt08QH9EQT0OH6l2mjM6TDXgg4K1qPiqN9EnzTQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TJFISS3fPUcd6DEOOP0W+iLg/MehqWAKn84NatA9HD2x9ox4VLLzoRForSafJLD5Z 7bknIRzjCT4DAd3BU/lMIEJKmiIGlav6YBMZMbz/DN4vug1w5ufeLyipa8GyG6ee/E 2VBwwcud1ujgQzDiV0AkCdaD7egYm3HrIcJ+CWH2QlbK/4r+shqzCLAI8Y66FlC6Qm Df/4O359q3sLIf8HsChGbNGebitD1yY8qQTqMgKU2HRSnIW4bSh5OtY1xFENmbcjcw CvvFesh2ElTtCjgpJuW7rKi4ipanh0qwGxR5nqaPQG5AFADuX/VcD+oLP/Ps2rpJT6 4j5kRjU+IlUHw== Date: Tue, 16 Apr 2024 21:18:02 +0300 From: Mike Rapoport To: Matthew Wilcox Cc: Nam Cao , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , Christian Brauner , Andreas Dilger , Al Viro , linux-fsdevel , Jan Kara , Linux Kernel Mailing List , linux-riscv@lists.infradead.org, Theodore Ts'o , Ext4 Developers List , Conor Dooley , Anders Roxell , Alexandre Ghiti Subject: Re: riscv32 EXT4 splat, 6.8 regression? Message-ID: References: <20240416-deppen-gasleitung-8098fcfd6bbd@brauner> <8734rlo9j7.fsf@all.your.base.are.belong.to.us> <20240416171713.7d76fe7d@namcao> Precedence: bulk X-Mailing-List: linux-fsdevel@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: On Tue, Apr 16, 2024 at 05:31:51PM +0100, Matthew Wilcox wrote: > On Tue, Apr 16, 2024 at 07:19:27PM +0300, Mike Rapoport wrote: > > > "last page of the first gigabyte" - why first gigabyte? Do you mean > > > last page of *last* gigabyte? > > > > With 3G-1G split linear map can map only 1G from 0xc0000000 to 0xffffffff > > (or 0x00000000 with 32-bit overflow): > > > > [ 0.000000] lowmem : 0xc0000000 - 0x00000000 (1024 MB) > > ... but you can't map that much. You need to reserve space for (may not > be exhaustive): > > - PCI BARs (or other MMIO) > - vmap > - kmap > - percpu > - ioremap > - modules > - fixmap > - Maybe EFI runtime services? > > You'll be lucky to get 800MB of ZONE_NORMAL. But that does not mean that the last page won't get to the buddy -- Sincerely yours, Mike.