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sukadev@linux.vnet.ibm.com authored
The 24x7 counters are continuously running and not updated on an interrupt. So we record the event counts when stopping the event or deleting it. But to "read" a single counter in 24x7, we allocate a page and pass it into the hypervisor (The HV returns the page full of counters from which we extract the specific counter for this event). We allocate a page using GFP_USER and when deleting the event, we end up with the following warning because we are blocking in interrupt context. [ 698.641709] BUG: scheduling while atomic: swapper/0/0/0x10010000 We could use GFP_ATOMIC but that could result in failures. Pre-allocate a buffer so we don't have to allocate in interrupt context. Further as Michael Ellerman suggested, use Per-CPU buffer so we only need to allocate once per CPU. Cc: stable@vger.kernel.org Signed-off-by:
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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