atomic operations in user space
LeoLi at freescale.com
Tue Aug 29 23:37:37 EST 2006
> This is exactly how it is supposed to work! That's why there is a loop
> in the atomic increment - you check if you still had the reservation
> after the transaction by checking the result from the stwcx, and if not,
I surely know all the theories you mentioned clearly. But please do
look at the case I gave. Correct me if I missed anything. Thanks
All the lwarx and stwcx operate on the same address.
> Task A Task B
// Get RESERVATION
// RESERVATION cleared
// Get RESERVATION again
//Note here: RESERVATION is valid, address is the same.
So the result is commited, no retry for task A
//RESERVATION is cleared, retry atomic op for task B
Please be noted that reservation is only identified by reservation bit
and address operated on. So different lwarx's on the same address,
may be considered as the same reservation.
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