From: Matthew Wilcox <willy@infradead.org>
To: Mike Rapoport <rppt@kernel.org>
Cc: "Nam Cao" <namcao@linutronix.de>,
"Björn Töpel" <bjorn@kernel.org>,
"Christian Brauner" <brauner@kernel.org>,
"Andreas Dilger" <adilger@dilger.ca>,
"Al Viro" <viro@zeniv.linux.org.uk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"Jan Kara" <jack@suse.cz>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-riscv@lists.infradead.org, "Theodore Ts'o" <tytso@mit.edu>,
"Ext4 Developers List" <linux-ext4@vger.kernel.org>,
"Conor Dooley" <conor@kernel.org>,
"Anders Roxell" <anders.roxell@linaro.org>,
"Alexandre Ghiti" <alex@ghiti.fr>
Subject: Re: riscv32 EXT4 splat, 6.8 regression?
Date: Tue, 16 Apr 2024 17:31:51 +0100 [thread overview]
Message-ID: <Zh6n952Y7qKRMnMj@casper.infradead.org> (raw)
In-Reply-To: <Zh6lD8d7cUZdkZJb@kernel.org>
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.
next prev parent reply other threads:[~2024-04-16 16:31 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-12 14:57 riscv32 EXT4 splat, 6.8 regression? Björn Töpel
2024-04-12 15:43 ` Theodore Ts'o
2024-04-12 16:59 ` Björn Töpel
2024-04-13 4:35 ` Theodore Ts'o
2024-04-13 10:01 ` Conor Dooley
2024-04-13 14:43 ` Nam Cao
2024-04-14 0:24 ` Theodore Ts'o
2024-04-14 1:46 ` Andreas Dilger
2024-04-14 2:04 ` Theodore Ts'o
2024-04-14 2:18 ` Al Viro
2024-04-14 2:15 ` Al Viro
2024-04-14 4:16 ` Andreas Dilger
2024-04-14 14:08 ` Björn Töpel
2024-04-15 13:04 ` Christian Brauner
2024-04-15 16:04 ` Björn Töpel
2024-04-16 6:44 ` Nam Cao
2024-04-16 8:25 ` Christian Brauner
2024-04-16 11:02 ` Björn Töpel
2024-04-16 14:24 ` Mike Rapoport
2024-04-16 15:17 ` Nam Cao
2024-04-16 15:30 ` Nam Cao
2024-04-16 15:56 ` Björn Töpel
2024-04-16 16:19 ` Nam Cao
2024-04-16 16:31 ` Mike Rapoport
2024-04-16 17:00 ` Matthew Wilcox
2024-04-16 18:34 ` Mike Rapoport
2024-04-16 22:36 ` Nam Cao
2024-04-17 15:31 ` Theodore Ts'o
2024-04-17 18:06 ` Nam Cao
2024-04-17 19:34 ` Mike Rapoport
2024-04-17 22:09 ` Andreas Dilger
2024-04-18 9:17 ` Nam Cao
2024-04-16 18:05 ` Björn Töpel
2024-04-16 18:09 ` Nam Cao
2024-04-16 16:19 ` Mike Rapoport
2024-04-16 16:31 ` Matthew Wilcox [this message]
2024-04-16 18:18 ` Mike Rapoport
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