Messages in this thread | | | Date | Mon, 20 Mar 2017 15:28:07 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t |
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On Mon, Mar 20, 2017 at 02:10:24PM +0000, David Laight wrote: > On x86 the cpu flags from the 'lock inc/dec' could be used to reasonably > cheaply detect errors - provided you actually generate a forwards branch.
Note that currently there is no arch specific implementation. We could of course cure this.
But note that the thing you propose; using the overflow flag, can only reasonably be done on PREEMPT=n kernels, otherwise we have an incredible number of contexts that can nest.
Sure; getting all starts aligned to double overflow is incredibly rare, but I don't want to be the one to have to debug that.
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