Messages in this thread | | | Date | Mon, 11 Mar 2002 14:45:49 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [PATCH] Futexes IV (Fast Lightweight Userspace Semaphores) |
| |
On Sat, 9 Mar 2002, Rusty Russell wrote: > > > > So I would suggest making the size (and thus alignment check) of locks at > > least 8 bytes (and preferably 16). That makes it slightly harder to put > > locks on the stack, but gcc does support stack alignment, even if the code > > sucks right now. > > Actually, I disagree. > > 1) We've left wiggle room in the second arg to sys_futex() to add rwsems > later if required. > 2) Someone needs to implement them and prove they are superior to the > pure userspace solution.
You've convinced me.
Considering how long people argued about dubious cycle measurements on the rwsem implementation, and where the crrent one actually uses a spinlock for exclusion on the fast path, the kernel lock really probably doesn't need to be expanded, and as there is provable overhead to the expansion, I'll just agree with you.
Applied.
Linus
- 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/
| |