bpf: Convert percpu_freelist.c to rqspinlock

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Convert the percpu_freelist.c code to use rqspinlock, and remove the
extralist fallback and trylock-based acquisitions to avoid deadlocks.

Key thing to note is the retained while (true) loop to search through
other CPUs when failing to push a node due to locking errors. This
retains the behavior of the old code, where it would keep trying until
it would be able to successfully push the node back into the freelist of
a CPU.

Technically, we should start iteration for this loop from
raw_smp_processor_id() + 1, but to avoid hitting the edge of nr_cpus,
we skip execution in the loop body instead.

Closes: https://lore.kernel.org/bpf/CAPPBnEa1_pZ6W24+WwtcNFvTUHTHO7KUmzEbOcMqxp+m2o15qQ@mail.gmail.com
Closes: https://lore.kernel.org/bpf/CAPPBnEYm+9zduStsZaDnq93q1jPLqO-PiKX9jy0MuL8LCXmCrQ@mail.gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250316040541.108729-21-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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This commit is contained in:

Kumar Kartikeya Dwivedi 2025-03-15 21:05:36 -07:00 • committed by Alexei Starovoitov

parent 4fa8d68aa5

commit f2ac0e5d1c

2 changed files with 27 additions and 90 deletions

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119

kernel/bpf/percpu_freelist.c

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4

kernel/bpf/percpu_freelist.h

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