On Thu, Apr 16, 2020 at 09:42:41PM -0400, Qian Cai wrote:
> So, this is still not enough that would still trigger storage driver offline
> under
> memory pressure for a bit longer. It looks to me that in fetch_pte() there are
> could still racy?
Yes, your patch still looks racy. You need to atomically read
domain->pt_root to a stack variable and derive the pt_root pointer and
the mode from that variable instead of domain->pt_root directly. If you
read the domain->pt_root twice there could still be an update between
the two reads.
Probably the lock in increase_address_space() can also be avoided if
pt_root is updated using cmpxchg()?
Regards,
Joerg
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