Re: [PATCH] Profile likely/unlikely macros

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Andrew Morton wrote:
Daniel Walker <[email protected]> wrote:

+	if (likeliness->type & LIKELY_UNSEEN) {
+		if (atomic_dec_and_test(&likely_lock)) {
+			if (likeliness->type & LIKELY_UNSEEN) {
+				likeliness->type &= (~LIKELY_UNSEEN);
+				likeliness->next = likeliness_head;
+				likeliness_head = likeliness;
+			}
+		}
+		atomic_inc(&likely_lock);


hm, good enough I guess.  It does need a comment explaining why we
don't just do spin_lock().

I guess it is so it can be used in NMIs and interrupts without turning
interrupts off (so is somewhat lightweight).

But please Daniel, just use spinlocks and trylock. This is buggy because
it doesn't get the required release consistency correct.

--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com -
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux