Nick Piggin wrote:
Zachary Amsden wrote:
Similar to the last bug, on set_pte, we don't want the compiler to
re-order
the write of the PTE, even in non-SMP configurations, since if the
write of
the low word occurs first, the TLB could prefetch a bad highmem
mapping which
has been aliased into low memory.
wmb() means that it also orders IO memory. It is no difference for
i386, but smp_wmb() actually has the right semantics of the abstract
Linux memory model.
The name is pretty confused. smp_wmb seems to imply an SMP-only
barrier, whereas we want here a write barrier on regular memory. Both
smp_wmb and wmb() are identical in that they both reduce to barrier
today, but I confess not to know which one semantically is correct.
Your call on this patch - it is unecessary, I thought it was more
semantically correct, but you probably know that better than me. So,
drop part 2 of this patch?
Zach
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
