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From: Pasha Tatashin <pasha.tatashin@soleen.com>
Date: Mon, 11 Mar 2024 20:23:40 -0400
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Subject: Re: [RFC 11/14] x86: add support for Dynamic Kernel Stacks
To: Andy Lutomirski <luto@kernel.org>
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> >
> > You can't block when scheduling, either.  What if you can't refill the pool?
>
> Why can't we (I am not a scheduler guy)? IRQ's are not yet disabled,
> what prevents us from blocking while the old process has not yet been
> removed from the CPU?

Answering my own question: single cpu machine, the thread is going
away, but tries to refill the dynamic-pages, alloc_page() goes into
slow path i.e (__alloc_pages_slowpath), where it performs
cond_resched() while waiting for oom kills, and yet we cannot leave
the CPU.