Re: [RESEND RFC PATCH 0/3] Provide fast access to thread specific data

On Mon, Sep 13, 2021 at 10:36 AM Prakash Sangappa
[off-list ref] wrote:

[...]

quoted

This sounds, again, as if the kernel should be aware of the kind of
items being allocated; having a more generic mechanism of allocating
pinned memory for the userspace to use at its discretion would be more
generally useful, I think. But how then the kernel/system should be
protected from a buggy or malicious process trying to grab too much?

One option would be to have a generic in-kernel mechanism for this,
but expose it to the userspace via domain-specific syscalls that do
the accounting you hint at. This sounds a bit like an over-engineered
solution, though…

What will this pinned memory be used for in your use case,
can you explain?

For userspace scheduling, to share thread/task state information
between the kernel and the userspace. This memory will be allocated
per task/thread; both the kernel and the userspace will write to the
shared memory, and these reads/writes will happen not only in the
memory regions belonging to the "current" task/thread, but also to
remote tasks/threads.

Somewhat detailed doc/rst is here:
https://lore.kernel.org/lkml/20210908184905.163787-5-posk@google.com/ (local)