workqueue: Add workqueue_bh_budget_yield tracepoint

Bottom-Half (BH) workqueues execute work items in softirq context.
To prevent softirqs from starving user and kernel threads, bh_worker()
enforces execution limits (i.e., BH_WORKER_JIFFIES and BH_WORKER_RESTARTS).

When keep_working() is still true but either the time slice or restart
count is exhausted, bh_worker() yields execution and re-raises the
softirq via kick_bh_pool().

Currently, there is no observability into when a BH worker hits these
limits and is forced to yield.

Add the workqueue_bh_budget_yield tracepoint, emitted when bh_worker() exits
the processing loop with pending work items remaining. It records, the
worker pool ID, pool CPU, number of loop restarts consumed, a boolean flag
indicating whether the yield was due to a time slice timeout, and a boolean
flag indicating whether this is a high-priority BH pool.

Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

0 files changed, 0 insertions, 0 deletions