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[0/8] sched: Use lock guards, wave 2

Message ID 20230809202440.012625269@infradead.org
Headers
Series sched: Use lock guards, wave 2 |

Message

Peter Zijlstra Aug. 9, 2023, 8:24 p.m. UTC 
  Hi, as promised, here is the second part of the SBRM patches.

Now that we're a little used to them, these are a little more involved.

New in this series, over the guard()() and scoped_guard () usage, is CLASS().

CLASS() is very like guard() except it also takes a name argument. So where
guard() instantiates an 'anonymous' variable, CLASS() instantiates an
explicitly named one.

  CLASS(task_rq_lock, rq_guard)(p);

which can be read like:

  class_task_rq_lock_t rq_guard __cleanup(class_task_rq_lock_destructor) =
	class_task_rq_lock_constructor(p);

[[ Notable: guard(name) := CLASS(name, __UNIQUE_ID(guard)) ]]

The advantage in this specific case is that the guard object of task_rq_lock
will contain the 'struct rq *' which we'll need.

Another use of CLASS() is:

  CLASS(find_get_task, p)(pid);

Where 'p' is of 'struct task_struct *' type and the constructor does the
pid->task_struct lookup and the destructor does put_task_struct.

Again, mostly aimed at getting rid of error gotos. The final patch is a bunch
of random conversions that happened while I was poking around and playing with
things.

Also available at:

  git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/guards2


Next in line is kernel/events/core.c, but I might not bore all of you with those
patches :-)