net: openvswitch: reduce cpu_used_mask memory
Use actual CPU number instead of hardcoded value to decide the size of 'cpu_used_mask' in 'struct sw_flow'. Below is the reason. 'struct cpumask cpu_used_mask' is embedded in struct sw_flow. Its size is hardcoded to CONFIG_NR_CPUS bits, which can be 8192 by default, it costs memory and slows down ovs_flow_alloc. To address this: Redefine cpu_used_mask to pointer. Append cpumask_size() bytes after 'stat' to hold cpumask. Initialization cpu_used_mask right after stats_last_writer. APIs like cpumask_next and cpumask_set_cpu never access bits beyond cpu count, cpumask_size() bytes of memory is enough. Signed-off-by: Eddy Tao <taoyuan_eddy@hotmail.com> Acked-by: Eelco Chaudron <echaudro@redhat.com> Link: https://lore.kernel.org/r/OS3P286MB229570CCED618B20355D227AF5D59@OS3P286MB2295.JPNP286.PROD.OUTLOOK.COMSigned-off-by: Jakub Kicinski <kuba@kernel.org>
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