Re: [PATCH v3 2/2] blk-mq: expose tag starvation counts via debugfs

[Bart Van Assche]

On 3/19/26 3:19 PM, Aaron Tomlin wrote:
To guarantee zero performance overhead for production kernels compiled
without debugfs, the underlying atomic_t variables and their associated
increment routines are strictly guarded behind CONFIG_BLK_DEBUG_FS.
When this configuration is disabled, the tracking logic compiles down
to a safe no-op.

I don't think that's sufficient. Please use per-cpu counters to minimize 
the overhead for kernels in which debugfs is enabled.

Thanks,

Bart.