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Andres Lagar-Cavilla authored
Per page operations in the paging, sharing, and access tracking subsystems are all implemented with domctls (e.g. a domctl to evict one page, or to share one page). Under heavy load, the domctl path reveals a lack of scalability. The domctl lock serializes dom0's vcpus in the hypervisor. When performing thousands of per-page operations on dozens of domains, these vcpus will spin in the hypervisor. Beyond the aggressive locking, an added inefficiency of blocking vcpus in the domctl lock is that dom0 is prevented from re-scheduling any of its other work-starved processes. We retain the domctl interface for setting up and tearing down paging/sharing/mem access for a domain. But we migrate all the per page operations to use the memory_op hypercalls (e.g XENMEM_*). Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla> Signed-off-by: Adin Scannell <adin@scannell.ca> Acked-by: Tim Deegan <tim@xen.org> Acked-by: Ian Jackson <ian.jackson@eu.citrix.com> Committed-by: Tim Deegan <tim@xen.org>
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