Re: [PATCH v2] x86: update comment about pgd_list

["H. Peter Anvin" <hpa@zytor.com>]

On 2026-05-11 04:35, Brendan Jackman wrote:
> On Mon Mar 23, 2026 at 2:25 PM UTC, Brendan Jackman wrote:
>> This venerable comment got detached from its context when the code moved
>> in commit 394158559d4c ("x86: move all the pgd_list handling to one
>> place"). Put it back next to its context. It was originally on
>> pgd_list_add() but it actually describes pgd_list so put it there.
>>
>> While moving it, update it to strip away stale and superfluous info.
>> pageattr.c doesn't exist any more. pgd_list is now required
>> for all x86 architectures. Also be slightly more precise about what PGDs
>> are in this list.
>>
>> Signed-off-by: Brendan Jackman <jackmanb@google.com>
>> ---
>> Changes in v2:
>> - Moved it next to pgd_list instead of back to old location
>> - Strip away stale bits from the comment
>> - Added note about PGDs that _aren't_ in this list
>> - Link to v1: https://lore.kernel.org/r/20260311-pgd_list-comment-v1-1-4ea51b41adee@google.com
> 
> Hi Dave,
> 
> I think this is ready?
> 
> (I don't see it in tip/master, apologies if I'm looking in the wrong
> place).

The PAE code comment should still remain.

I don't know if the 32-bit PAE code is still suffering from Xen-induced drain
bramage (using a whole page to store 32 bytes), but it is nevertheless true in
a fashion -- as there are a maximum of 3 kernel PDE pages, they are considered
the de facto top level of the kernel page tables.

	-hpa