Messages in this thread Patch in this message | | | From | Pierre Morel <> | Subject | [PATCH v3 3/3] s390x: optimization of the check for CPU topology change | Date | Tue, 3 Aug 2021 10:26:46 +0200 |
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Now that the PTF instruction is interpreted by the SIE we can optimize the arch_update_cpu_topology callback to check if there is a real need to update the topology by using the PTF instruction.
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> --- arch/s390/kernel/topology.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c index 26aa2614ee35..741cb447e78e 100644 --- a/arch/s390/kernel/topology.c +++ b/arch/s390/kernel/topology.c @@ -322,6 +322,9 @@ int arch_update_cpu_topology(void) struct device *dev; int cpu, rc; + if (!ptf(PTF_CHECK)) + return 0; + rc = __arch_update_cpu_topology(); on_each_cpu(__arch_update_dedicated_flag, NULL, 0); for_each_online_cpu(cpu) { -- 2.25.1
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