[PATCH bpf-next v2 11/26] rqspinlock: Add deadlock detection and recovery
Peter Zijlstra
peterz at infradead.org
Mon Feb 10 02:36:25 PST 2025
On Thu, Feb 06, 2025 at 02:54:19AM -0800, Kumar Kartikeya Dwivedi wrote:
> + /*
> + * Find the CPU holding the lock that we want to acquire. If there is a
> + * deadlock scenario, we will read a stable set on the remote CPU and
> + * find the target. This would be a constant time operation instead of
> + * O(NR_CPUS) if we could determine the owning CPU from a lock value, but
> + * that requires increasing the size of the lock word.
> + */
Is increasing the size of rqspinlock_t really a problem? For the kernel
as a whole there's very little code that really relies on spinlock_t
being u32 (lockref is an example that does care).
And it seems to me this thing might benefit somewhat significantly from
adding this little extra bit.
More information about the linux-arm-kernel
mailing list