On Fri, 2 Dec 2011, Mikael Pettersson wrote: > but futexes must be 32-bit aligned (or at least not cross page > boundaries).
Don't mix up futexes with hardware-mandated atomic alignment (except that preferably the letter should not be more strict). Linux futexes must be 32-bit aligned *for all architectures*. Linux uses the two low bits for its own purposes, when it stores futex addresses internally (or something to that effect; it was a while ago I looked at this, around Feb 2009 alt. 2.6.27-ish). brgds, H-P
