From: Nam Cao <namcao@linutronix.de>
To: Mike Rapoport <rppt@kernel.org>
Cc: "Matthew Wilcox" <willy@infradead.org>,
"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: Wed, 17 Apr 2024 00:36:39 +0200 [thread overview]
Message-ID: <20240417003639.13bfd801@namcao> (raw)
In-Reply-To: <Zh7Ey507KXIak8NW@kernel.org>
On 2024-04-16 Mike Rapoport wrote:
> On Tue, Apr 16, 2024 at 06:00:29PM +0100, Matthew Wilcox wrote:
> > On Tue, Apr 16, 2024 at 07:31:54PM +0300, Mike Rapoport wrote:
> > > > - if (!IS_ENABLED(CONFIG_64BIT)) {
> > > > - max_mapped_addr = __pa(~(ulong)0);
> > > > - if (max_mapped_addr == (phys_ram_end - 1))
> > > > - memblock_set_current_limit(max_mapped_addr - 4096);
> > > > - }
> > > > + memblock_reserve(__pa(-PAGE_SIZE), PAGE_SIZE);
> > >
> > > Ack.
> >
> > Can this go to generic code instead of letting architecture maintainers
> > fall over it?
>
> Yes, it's just have to happen before setup_arch() where most architectures
> enable memblock allocations.
This also works, the reported problem disappears.
However, I am confused about one thing: doesn't this make one page of
physical memory inaccessible?
Is it better to solve this by setting max_low_pfn instead? Then at
least the page is still accessible as high memory.
Best regards,
Nam
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index fa34cf55037b..6e3130cae675 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -197,7 +197,6 @@ early_param("mem", early_mem);
static void __init setup_bootmem(void)
{
phys_addr_t vmlinux_end = __pa_symbol(&_end);
- phys_addr_t max_mapped_addr;
phys_addr_t phys_ram_end, vmlinux_start;
if (IS_ENABLED(CONFIG_XIP_KERNEL))
@@ -235,23 +234,9 @@ static void __init setup_bootmem(void)
if (IS_ENABLED(CONFIG_64BIT))
kernel_map.va_pa_offset = PAGE_OFFSET - phys_ram_base;
- /*
- * memblock allocator is not aware of the fact that last 4K bytes of
- * the addressable memory can not be mapped because of IS_ERR_VALUE
- * macro. Make sure that last 4k bytes are not usable by memblock
- * if end of dram is equal to maximum addressable memory. For 64-bit
- * kernel, this problem can't happen here as the end of the virtual
- * address space is occupied by the kernel mapping then this check must
- * be done as soon as the kernel mapping base address is determined.
- */
- if (!IS_ENABLED(CONFIG_64BIT)) {
- max_mapped_addr = __pa(~(ulong)0);
- if (max_mapped_addr == (phys_ram_end - 1))
- memblock_set_current_limit(max_mapped_addr - 4096);
- }
-
min_low_pfn = PFN_UP(phys_ram_base);
- max_low_pfn = max_pfn = PFN_DOWN(phys_ram_end);
+ max_pfn = PFN_DOWN(phys_ram_end);
+ max_low_pfn = min(max_pfn, PFN_DOWN(__pa(-PAGE_SIZE)));
high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
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next prev parent reply other threads:[~2024-04-16 22:36 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 [this message]
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
2024-04-16 18:18 ` Mike Rapoport
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