[12/17] Virtual Compound page allocation from interrupt context.

In an interrupt context we cannot wait for the vmlist_lock in __get_vm_area_node(). So use a trylock instead. If the trylock fails then the atomic allocation will fail and subsequently be retried. This only works because the flush_cache_vunmap in use for allocation is never performing any IPIs in

[12/17] Virtual Compound page allocation from interrupt context.

In an interrupt context we cannot wait for the vmlist_lock in __get_vm_area_node(). So use a trylock instead. If the trylock fails then the atomic allocation will fail and subsequently be retried. This only works because the flush_cache_vunmap in use for allocation is never performing any IPIs in