On Fri, 2006-07-14 at 20:22 -0600, Matthew Wilcox wrote: > On Fri, Jul 14, 2006 at 04:05:01PM -0400, Steven Rostedt wrote: > > There are some more advanced barrier functions: > > > > (*) set_mb(var, value) > > - (*) set_wmb(var, value) > > > > - These assign the value to the variable and then insert at least a > > write > > - barrier after it, depending on the function. They aren't guaranteed > > to > > + This assigns the value to the variable and then inserts at least a > > write > > + barrier after it, depending on the function. It isn't guaranteed to > > insert anything more than a compiler barrier in a UP compilation. > > "There is one more advanced barrier function"? ;-) Or did you want to > remove set_mb()?
Actually below the patch area we still have: (*) smp_mb__before_atomic_dec(); (*) smp_mb__after_atomic_dec(); (*) smp_mb__before_atomic_inc(); (*) smp_mb__after_atomic_inc(); So that "There are" references them too :) > > Plus, the "depending on the function" bit means "respectively". So what > you really want as help is something like: > > This assigns the value to the variable and then inserts a > barrier after the assignment. It isn't guaranteed to insert > anything more than a compiler barrier in a UP compilation. OK, you're right here, that "depending on the function" needs to go. Here's a better version: Thanks, -- Steve Signed-off-by: Steven Rostedt <[EMAIL PROTECTED]> Index: linux-2.6.18-rc1/Documentation/memory-barriers.txt =================================================================== --- linux-2.6.18-rc1.orig/Documentation/memory-barriers.txt 2006-07-14 15:38:23.000000000 -0400 +++ linux-2.6.18-rc1/Documentation/memory-barriers.txt 2006-07-14 22:31:01.000000000 -0400 @@ -1015,11 +1015,10 @@ CPU from reordering them. There are some more advanced barrier functions: (*) set_mb(var, value) - (*) set_wmb(var, value) - These assign the value to the variable and then insert at least a write - barrier after it, depending on the function. They aren't guaranteed to - insert anything more than a compiler barrier in a UP compilation. + This assigns the value to the variable and then inserts a memory barrier + after it. It isn't guaranteed to insert anything more than a compiler + barrier in a UP compilation. (*) smp_mb__before_atomic_dec(); - To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
