On 1/19/2018 12:21 AM, Steven Rostedt wrote:
On Thu, 18 Jan 2018 13:01:46 +0900
Byungchul Park <byungchul.park@xxxxxxx> wrote:
I disagree. It is like a spinlock. You can say a spinlock() that is
blocked is also waiting for an event. That event being the owner does a
spin_unlock().
That's exactly what I was saying. Excuse me but, I don't understand
what you want to say. Could you explain more? What do you disagree?
I guess I'm confused at what you are asking for then.
Sorry for not enough explanation. What I asked you for is:
1. Relocate acquire()s/release()s.
2. So make it simpler and remove unnecessary one.
3. So make it look like the following form,
because it's a thing simulating "wait and event".
A context
---------
lock_map_acquire(wait); /* Or lock_map_acquire_read(wait) */
/* "Read" one is better though.. */
/* A section, we suspect a wait for an event might happen. */
...
lock_map_release(wait);
The place actually doing the wait
---------------------------------
lock_map_acquire(wait);
lock_map_release(wait);
wait_for_event(wait); /* Actually do the wait */
Honestly, you used acquire()s/release()s as if they are cross-
release stuff which mainly handles general waits and events,
not only things doing "acquire -> critical area -> release".
But that's not in the mainline at the moment.
I find your way confusing. I'm simulating a spinlock not a wait for
completion. A wait for completion usually initiates something then
I used the word, *event* instead of *completion*. wait_for_completion()
and complete() are just an example of a pair of waiter and event.
Lock and unlock can also be another example, too.
Important thing is that who waits and who triggers the event. Using the
pair, we can achieve various things, for examples:
1. Synchronization like wait_for_completion() does.
2. Control exclusively entering into a critical area.
3. Whatever.
waits for it to complete. This is trying to get into a critical area
but another task is currently in it. It's simulating a spinlock as far
as I can see.
Anyway it's an example of "waiter for an event, and the event".
JFYI, spinning or sleeping does not matter. Those are just methods to
^
whether spining or sleeping doesn't matter.
achieve a wait. I know you're not talking about this though. It's JFYI.
OK, if it is just FYI.
Actually, the last paragraph is JFYI tho.
-- Steve
--
Thanks,
Byungchul
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
