Messages in this thread | | | Date | Thu, 10 Aug 2006 06:41:35 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] memory ordering in __kfifo primitives |
| |
On Thu, Aug 10, 2006 at 01:48:02AM -0400, Mike Christie wrote: > Paul E. McKenney wrote: > > OK, it appears that we are even. I forgot to attach the promised > > analysis of the callers to __kfifo_put() and __kfifo_get(), and > > the open-iscsi@googlegroups.com email address listed as maintainer > > in drivers/scsi/libiscsi.c bounces complaining that, as a non-member, > > I am not allowed to send it email. ;-) > > Sorry about that. I do not have any control over the email list. I will > change the maintainer info entry to indicate that users should just send > mail to me or linux-scsi.
Sounds good!
> > Anyway, this time the analysis really is attached, sorry for my confusion! > > We have change the code a little since the analysis was made. But, it > does not really matter much now. I am fine with us just grabbing the > session lock or xmitmitex (I will send a patch and test it as well) if > your barrier patch is not accepted. We grab the session lock in the fast > path now so there is not much benefit left for us.
I am happy to go either way -- the patch with the memory barriers (which does have the side-effect of slowing down kfifo_get() and kfifo_put(), by the way), or a patch removing the comments saying that it is OK to invoke __kfifo_get() and __kfifo_put() without locking.
Any other thoughts on which is better? (1) the memory barriers or (2) requiring the caller hold appropriate locks across calls to __kfifo_get() and __kfifo_put()?
Thanx, Paul - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |