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由 Toshi Kani 提交于
The kernel initializes CPU & memory's NUMA topology from ACPI SRAT table. Some other ACPI tables, such as NFIT and DMAR, also contain proximity IDs for their device's NUMA topology. This information can be used to improve performance of these devices. This patch introduces acpi_map_pxm_to_online_node(), which is similar to acpi_map_pxm_to_node(), but always returns an online node. When the mapped node from a given proximity ID is offline, it looks up the node distance table and returns the nearest online node. ACPI device drivers, which are called after the NUMA initialization has completed in the kernel, can call this interface to obtain their device NUMA topology from ACPI tables. Such drivers do not have to deal with offline nodes. A node may be offline when a device proximity ID is unique, SRAT memory entry does not exist, or NUMA is disabled, ex. "numa=off" on x86. This patch also moves the pxm range check from acpi_get_node() to acpi_map_pxm_to_node(). Signed-off-by: NToshi Kani <toshi.kani@hp.com> Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>> Signed-off-by: NDan Williams <dan.j.williams@intel.com>
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