On Fri, Apr 03, 2020 at 08:30:59PM +0800, Huang, Ying wrote: > From: Huang Ying <ying.huang@xxxxxxxxx> > > Now, when read /proc/PID/smaps, the PMD migration entry in page table is simply > ignored. To improve the accuracy of /proc/PID/smaps, its parsing and processing > is added. > > To test the patch, we run pmbench to eat 400 MB memory in background, then run > /usr/bin/migratepages and `cat /proc/PID/smaps` every second. The issue as > follows can be reproduced within 60 seconds. > > Before the patch, for the fully populated 400 MB anonymous VMA, some THP pages > under migration may be lost as below. > > 7f3f6a7e5000-7f3f837e5000 rw-p 00000000 00:00 0 > Size: 409600 kB > KernelPageSize: 4 kB > MMUPageSize: 4 kB > Rss: 407552 kB > Pss: 407552 kB > Shared_Clean: 0 kB > Shared_Dirty: 0 kB > Private_Clean: 0 kB > Private_Dirty: 407552 kB > Referenced: 301056 kB > Anonymous: 407552 kB > LazyFree: 0 kB > AnonHugePages: 405504 kB > ShmemPmdMapped: 0 kB > FilePmdMapped: 0 kB > Shared_Hugetlb: 0 kB > Private_Hugetlb: 0 kB > Swap: 0 kB > SwapPss: 0 kB > Locked: 0 kB > THPeligible: 1 > VmFlags: rd wr mr mw me ac > > After the patch, it will be always, > > 7f3f6a7e5000-7f3f837e5000 rw-p 00000000 00:00 0 > Size: 409600 kB > KernelPageSize: 4 kB > MMUPageSize: 4 kB > Rss: 409600 kB > Pss: 409600 kB > Shared_Clean: 0 kB > Shared_Dirty: 0 kB > Private_Clean: 0 kB > Private_Dirty: 409600 kB > Referenced: 294912 kB > Anonymous: 409600 kB > LazyFree: 0 kB > AnonHugePages: 407552 kB > ShmemPmdMapped: 0 kB > FilePmdMapped: 0 kB > Shared_Hugetlb: 0 kB > Private_Hugetlb: 0 kB > Swap: 0 kB > SwapPss: 0 kB > Locked: 0 kB > THPeligible: 1 > VmFlags: rd wr mr mw me ac > > Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> > Reviewed-by: Zi Yan <ziy@xxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> -- Kirill A. Shutemov
