fs: move mntput_no_expire() slowpath into a dedicated routine

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In the stock variant the compiler spills several registers on the stack
and employs stack smashing protection, adding even more code + a branch
on exit..

The actual fast path is small enough that the compiler inlines it for
all callers -- the symbol is no longer emitted.

Forcing noinline on it just for code-measurement purposes shows the fast
path dropping from 111 to 39 bytes.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20251114201803.2183505-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

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Mateusz Guzik 2025-11-14 21:18:03 +01:00 • committed by Christian Brauner

parent 6d228c181e

commit bfef6e1f34

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1 changed files with 22 additions and 16 deletions

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38

fs/namespace.c

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