Re: [PATCH] mm/page_alloc: document that alloc_pages_nolock() uses RCU

[Brendan Jackman]

On Wed May 20, 2026 at 5:16 AM CEST, Harry Yoo wrote:
>  > (I don't think there is even> any documentation of what noinstr means 
> at all, let alone the connection
>> with RCU).
>
> *flips through the documentation*
> Oh, perhaps Documentation/core-api/entry.rst?

Oh, you're right. The situation is way better than I thought, and now
I realise I have read this and it's probably where I learned about
this in the first place (I thought I learned it all from Junaid). I
apologise to the Documentation/ tree for my slander.

>> Note this is not claiming that any cgroup code called from the allocator
>> would actually break if this restriction was violated, it could very
>> well be that there's no real way for the allocator to act on a cgroup
>> that can disappear concurrently. But, since it's likely nobody has
>> verified this one way or another, better to just be safe and declare
>> that RCU is required. Allocating from an RCU-unsafe context seems a bit
>> crazy anyway.
>> 
>> Suggested-by: Junaid Shahid <jackmanb@xxxxxxxxxx>
>
> The email should be junaids@xxxxxxxxxx, not jackmanb@xxxxxxxxxx? ;)

Damn. It looks like this already went into mm-unstable but I guess
it's not a huge deal.