17 Oct
2019
17 Oct
'19
11:25 a.m.
From: Michal Hocko
Sent: 17 October 2019 12:05
...
Plus, I don't see any locking here, should this be WRITE_ONCE() at minimum?
Why would that matter? Do you expect several root processes race to set the value?
One of them wins. No one is going to notice is the value is set an extra time.
WRITE_ONCE() is rarely required. Probably only if other code is going to update the value after seeing the first write. (eg if you are unlocking a mutex - although they have to be more complex)
READ_ONCE() is a different matter. IMHO the compiler shouldn't be allowed to do more reads than the source requests.
David
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