On Thu, Jun 23, 2016 at 10:57:09PM -0700, Linus Torvalds wrote: > The non-RCU case basically never shows up in profiles (it used to, > with symlinks, but you fixed that case), and if it ever does I suspect > that the fix will be to make sure we don't fall out of rcu. > > So don't worry too much about __d_lookup() being a hot case, I don't > think it is. > > (Of course, if you have a load that shows me wrong, let's look at it > by all means. Maybe the loads I have used have been bad) BTW, speaking of that area - is there any reason why dentry_cmp() isn't simply return dentry_string_cmp(lockless_dereference(dentry->d_name.name), ct, tcount); other than "it predates lockless_dereference()"? The only difference is s/ACCESS_ONCE/READ_ONCE/, AFAICS - lockless_dereference() uses the latter these days. And that shouldn't be a problem; as the matter of fact, *all* remaining ACCESS_ONCE in fs/dcache.c look like they should become READ_ONCE. Objections? Al, digging through the barrier-related issues with dentries and peeling the paint off the walls in process... -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
