Cc: Linux Kernel Mailing List <linux-kernel@...>, <paulmck@...>, Nadia Derbey <Nadia.Derbey@...>, Andrew Morton <akpm@...>, Peter Zijlstra <peterz@...>, Pavel Emelianov <xemul@...>
We can't just revert that patch: with IDR, a global lock is mandatory :-(
We must either revert the whole idea of using IDR or live with the
reduced scalability.
Actually, there are further bugs: the undo structures are not
namespace-aware, thus semop with SEM_UNDO, unshare, create new array
with same id, but more semaphores, another semop with SEM_UNDO will
corrupt kernel memory :-(
I'll try to clean up the bugs first, then I'll look at the scalability
again.
--
Manfred
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