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| author | Pengyu Zhang <zpenya1314@gmail.com> | 2024-10-09 22:41:35 +0800 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2024-10-14 10:16:16 -0600 |
| commit | 6a32c8dfec8126040a3f5484f4f7301ca96d697c (patch) | |
| tree | 17991ba33d60984ba70185f19a3684f52fcc7213 | |
| parent | 443165227d20ad739d616b50adab4d8ade1c5296 (diff) | |
| download | lwn-6a32c8dfec8126040a3f5484f4f7301ca96d697c.tar.gz lwn-6a32c8dfec8126040a3f5484f4f7301ca96d697c.zip | |
Docs/mm: Fix a mistake for pfn in page_tables.rst
The documentation incorrectly calculate the pfn value as 0x3fffff,
which should be 0x3ffff instead. It is obtained by right-shifting
0xffffc000 by 14 bits.
This patch corrects the value to prevent any potential confusion
for developers referencing this document.
Signed-off-by: Pengyu Zhang <zpenya1314@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Zenghui Yu <zenghui.yu@linux.dev>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241009144135.12453-1-zpenya1314@gmail.com
| -rw-r--r-- | Documentation/mm/page_tables.rst | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/mm/page_tables.rst b/Documentation/mm/page_tables.rst index be47b192a596..e7c69cc32493 100644 --- a/Documentation/mm/page_tables.rst +++ b/Documentation/mm/page_tables.rst @@ -29,7 +29,7 @@ address. With a page granularity of 4KB and a address range of 32 bits, pfn 0 is at address 0x00000000, pfn 1 is at address 0x00001000, pfn 2 is at 0x00002000 and so on until we reach pfn 0xfffff at 0xfffff000. With 16KB pages pfs are -at 0x00004000, 0x00008000 ... 0xffffc000 and pfn goes from 0 to 0x3fffff. +at 0x00004000, 0x00008000 ... 0xffffc000 and pfn goes from 0 to 0x3ffff. As you can see, with 4KB pages the page base address uses bits 12-31 of the address, and this is why `PAGE_SHIFT` in this case is defined as 12 and |