Andi Kleen wrote:
I always wondered why the xchg is necessary here at all. If the process of
tearing down a page table entry has started, other users of the mapped
linear address are broken anyway - why is it necessary to still monitor the
effect they may have on the A/D bits, unless this is a transient tear down?
Checking for the uses of ptep_get_and_clear, I would judge that the use in
change_pte_range() may in fact need the xchg, but the uses in
vunmap_pte_range() and zap_pte_range() shouldn't.
Yes I agree. Might be a nice speed up for exit to distingush the cases.
That is what I did in this patch - but with care zap_pte_range can also
be called in non-teardown cases when unmapping (when !fullmm) and user
mappings could still be in effect on remote processors.
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]
