Post Syndicated from original https://lwn.net/Articles/835426/rss

The kernel’s tracing infrastructure is designed to be fast and to interfere
as little as possible with the normal operation of the system. One
consequence of this requirement is that the code that runs when a
tracepoint is hit cannot sleep; otherwise execution of the tracepoint could
add an arbitrary delay to the execution of the real work the kernel should
be doing. There are times, though, that the ability to sleep within a
tracepoint would be handy, delays notwithstanding. The sleepable
tracepoints patch set from Michael Jeanson sets the stage
to make it possible for (some) tracepoint
handlers to take a nap while performing their tasks — but stops short of
completing the job for now.