On 12/28/18 6:26 AM, kernel test robot wrote:
Greeting,
FYI, we noticed a -4.3% regression of vm-scalability.throughput due to commit:
commit: 9c83282117778856d647ffc461c4aede2abb6742 ("[PATCH v3 1/2] hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization") url: https://github.com/0day-ci/linux/commits/Mike-Kravetz/hugetlbfs-use-i_mmap_r...
in testcase: vm-scalability on test machine: 104 threads Intel(R) Xeon(R) Platinum 8170 CPU @ 2.10GHz with 64G memory with following parameters:
runtime: 300s size: 8T test: anon-cow-seq-hugetlb cpufreq_governor: performance ucode: 0x200004d
I'll take a closer look.
The patch does introduce longer i_mmap_rwsem hold times for the sake of correctness. Need to more fully understand the test and results to determine if this is expected.