From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 9633818C19; Wed, 17 Apr 2024 18:06:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713377183; cv=none; b=ifNPw6CnXWpvH2EtCdWQIZSn4/x8MIFP5ZBAu51Wd2FZF4ocxBOdyQ8a0hTv98WNT/3F69CdlMytIiH8bBTKVuZH6I9SETDVHKCVqTB/vNzP8gtNkWiNk3/nYPthiuWMRSIeFn8mo2ppR/p6er5uvJnLxMBw9dYySQJJlLQwFCo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713377183; c=relaxed/simple; bh=qDjvN97rYs9sHi5cS2z/zYzz/cV7lJgX2WvDgQPJW9s=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HRJQeUsg+YSu7/sUgT6OgJe3JZjqgBH7peO+OH7y24BhwVFifyPY77Gx6v2P4DzTTwdmSUkv4Dm4UQ4JHdXWTIjkxM1eW9/YpcewXyV7CWnWoVPnbJF3DPYIbNEfNkc1UoNPoSU04fVzDidQQ8LoJx5gnNj/JnusB3WS4aBeFWY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=PTnXRkL0; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=u0uvNqcx; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="PTnXRkL0"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="u0uvNqcx" Date: Wed, 17 Apr 2024 20:06:17 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1713377180; h=from:from: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; bh=pwylh6Dtd2mdV0b8+p19DcG02NblOYqwKMD1VZyGC1o=; b=PTnXRkL0Gx3ZvvovCOtl8ojNWOUmAw0Lw3c3YU2zdLPSfYxMnMlL0SvFTTJKO51paktGUV RGEh5iibetSJew8rfbQDbYxMPFffMsoVjmnPSMeFkKrqUAEttHCCzIN4d08NeOU8dnEXS6 tDoJj3Z0v4BSN1CBw6h4fiuzW/JMdPGt7RrAaPnPtGew3KXkHGx9qlYIDVa3+/LSAeysJx jylL0OQycAkKMO23FGGqqC0ilWzMUCyIjO6NiMh0QLRJXDeU5WrScnumsF4mZJDaVysAmb dYzAzJBTuZCDbDDplVOSCAv7rBJ+AKYUx1sdDUAZwpRE5Wl0W/t0FlhE9HQvZQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1713377180; h=from:from: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; bh=pwylh6Dtd2mdV0b8+p19DcG02NblOYqwKMD1VZyGC1o=; b=u0uvNqcxsrxeHeclsTeo2hclmfvQKtnv7ZQIvprFID5UogtYQNXGwTi1vc+sqQegdsu+K4 43uPtNQkpiHk8KCA== From: Nam Cao To: "Theodore Ts'o" Cc: Mike Rapoport , Matthew Wilcox , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Christian Brauner , Andreas Dilger , Al Viro , linux-fsdevel , Jan Kara , Linux Kernel Mailing List , linux-riscv@lists.infradead.org, Ext4 Developers List , Conor Dooley , Anders Roxell , Alexandre Ghiti Subject: Re: riscv32 EXT4 splat, 6.8 regression? Message-ID: <20240417200617.2f54bc7b@namcao> In-Reply-To: <20240417153122.GE2277619@mit.edu> References: <8734rlo9j7.fsf@all.your.base.are.belong.to.us> <20240416171713.7d76fe7d@namcao> <20240416173030.257f0807@namcao> <87v84h2tee.fsf@all.your.base.are.belong.to.us> <20240416181944.23af44ee@namcao> <20240417003639.13bfd801@namcao> <20240417153122.GE2277619@mit.edu> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On 2024-04-17 Theodore Ts'o wrote: > On Wed, Apr 17, 2024 at 12:36:39AM +0200, Nam Cao wrote: > > > > However, I am confused about one thing: doesn't this make one page of > > physical memory inaccessible? > > So are these riscv32 systems really having multiple terabytes of > memory? Why is this page in the physical memory map in the first > place? It's 32 bit, so it doesn't take much to fill up the entire address space. Here's the memory layout from kernel boot log: [ 0.000000] Virtual kernel memory layout: [ 0.000000] fixmap : 0x9c800000 - 0x9d000000 (8192 kB) [ 0.000000] pci io : 0x9d000000 - 0x9e000000 ( 16 MB) [ 0.000000] vmemmap : 0x9e000000 - 0xa0000000 ( 32 MB) [ 0.000000] vmalloc : 0xa0000000 - 0xc0000000 ( 512 MB) [ 0.000000] lowmem : 0xc0000000 - 0x00000000 (1024 MB) Note that lowmem occupies the last 1GB, including ERR_PTR (the last address wraps to zero) Best regards, Nam