The subject forgot to add "RT" in the brackets. On Fri, 29 Aug 2008, Andi Kleen wrote: > > I could just force all of the seqbegins to hit the slowpath by hacking > > the code and see what happens (aside from slowing down, of course ;) > > Only if you don't believe it will really crash? I think it's pretty > clear even without trying it. > > > Question: Which seqlock_t does userspace use? I assume it uses > > seqlock_t and not raw_seqlock_t. > > > But the only reason that I ask is that > > I converted raw_seqlock_t to use the new style as well to be consistent, > > There's no raw_seqlock_t anywhere in mainline? Nope, raw_seqlock_t in -rt is equivelant to seqlock_t in mainline. > > Anyways the variable is declared (in mainline) in asm-x86/vgtod.h > > > even though it is not strictly necessary for the same reasons. So if > > perchance userspace uses the raw variant, I could solve this issue by > > only re-working the seqlock_t variant. Kind of a long shot, but figured > > I would mention it :) > > I guess you could define a new seqlock_t which is explicitely user space > safe. That might avoid such issues in the future. But then > that would likely require some code duplication and be ugly. > > On the other hand whatever problem you fixing in the kernel > (to be honest it's still unclear to me what the problem is) > needs to be likely fixed for the userland lock too. I'm not convinced that the raw_seqlocks (mainline normal seqlocks) has a problem anyway. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
