On 2020-07-17 08:55, HORIGUCHI NAOYA wrote:
I ran Quan Cai's test program (https://github.com/cailca/linux-mm) on a small (4GB memory) VM, and weiredly found that (1) the target hugepages are not always dissolved and (2) dissovled hugetpages are still counted in "HugePages_Total:". See below: $ ./random 1 - start: migrate_huge_offline - use NUMA nodes 0,1. - mmap and free 8388608 bytes hugepages on node 0 - mmap and free 8388608 bytes hugepages on node 1 madvise: Cannot allocate memory $ cat /proc/meminfo MemTotal: 4026772 kB MemFree: 976300 kB MemAvailable: 892840 kB Buffers: 20936 kB Cached: 99768 kB SwapCached: 5904 kB Active: 84332 kB Inactive: 116328 kB Active(anon): 27944 kB Inactive(anon): 68524 kB Active(file): 56388 kB Inactive(file): 47804 kB Unevictable: 7532 kB Mlocked: 0 kB SwapTotal: 2621436 kB SwapFree: 2609844 kB Dirty: 56 kB Writeback: 0 kB AnonPages: 81764 kB Mapped: 54348 kB Shmem: 8948 kB KReclaimable: 22744 kB Slab: 52056 kB SReclaimable: 22744 kB SUnreclaim: 29312 kB KernelStack: 3888 kB PageTables: 2804 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 3260612 kB Committed_AS: 828196 kB VmallocTotal: 34359738367 kB VmallocUsed: 19260 kB VmallocChunk: 0 kB Percpu: 5120 kB HardwareCorrupted: 5368 kB AnonHugePages: 18432 kB ShmemHugePages: 0 kB ShmemPmdMapped: 0 kB FileHugePages: 0 kB FilePmdMapped: 0 kB CmaTotal: 0 kB CmaFree: 0 kB HugePages_Total: 1342 // still counted as hugetlb pages. HugePages_Free: 0 // all hugepage are still allocated (or leaked?) HugePages_Rsvd: 0 HugePages_Surp: 762 // some are counted in surplus. Hugepagesize: 2048 kB Hugetlb: 2748416 kB DirectMap4k: 112480 kB DirectMap2M: 4081664 kB $ page-types -b hwpoison flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000080008 421 1 ___U_______________X_______________________ uptodate,hwpoison 0x00000000000a8018 1 0 ___UD__________H_G_X_______________________ uptodate,dirty,compound_head,huge,hwpoison 0x00000000000a801c 920 3 __RUD__________H_G_X_______________________ referenced,uptodate,dirty,compound_head,huge,hwpoison total 1342 5 This means that some hugepages are dissolved, but the others not, maybe which is not desirable. I'll dig this more later but just let me share at first. A few minor comment below ...
Uhm, weird. I will be taking a look today. Thanks
