Mike Kravetz <mike.kravetz@xxxxxxxxxx> writes: > On 05/14/2018 05:57 PM, Huang, Ying wrote: >> From: Huang Ying <ying.huang@xxxxxxxxx> >> >> This is to take better advantage of huge page clearing >> optimization (c79b57e462b5d, "mm: hugetlb: clear target sub-page last >> when clearing huge page"). Which will clear to access sub-page last >> to avoid the cache lines of to access sub-page to be evicted when >> clearing other sub-pages. This needs to get the address of the >> sub-page to access, that is, the fault address inside of the huge >> page. So the hugetlb no page fault handler is changed to pass that >> information. This will benefit workloads which don't access the begin >> of the huge page after page fault. >> >> With this patch, the throughput increases ~28.1% in vm-scalability >> anon-w-seq test case with 88 processes on a 2 socket Xeon E5 2699 v4 >> system (44 cores, 88 threads). The test case creates 88 processes, >> each process mmap a big anonymous memory area and writes to it from >> the end to the begin. For each process, other processes could be seen >> as other workload which generates heavy cache pressure. At the same >> time, the cache miss rate reduced from ~36.3% to ~25.6%, the >> IPC (instruction per cycle) increased from 0.3 to 0.37, and the time >> spent in user space is reduced ~19.3% > > Since this patch only addresses hugetlbfs huge pages, I would suggest > making that more explicit in the commit message. Sure. Will revise it! > Other than that, the changes look fine to me. > >> Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> > > Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Thanks! Best Regards, Huang, Ying
