+cc linux-mm@kvack.org <mailto:linux-mm@kvack.org>

On 2020/4/26 19:21, Yang Yingliang wrote:
> Hi,
>
> When I doing the follow test in kernel-5.7-rc2, I found mem-free is 
> decreased
>
> #!/bin/sh
> cd /sys/fs/cgroup/memory/
>
> for((i=0;i<45;i++))
> do
>         for((j=0;j<60000;j++))
>         do
>                 mkdir /sys/fs/cgroup/memory/yyl-cg$j
>         done
>         sleep 1
>         ls /sys/fs/cgroup/memory/ | grep yyl | xargs rmdir
> done
>
>
> before test the /proc/meminfo is:
>
> MemTotal:       493554824 kB
> MemFree:        491240912 kB
> MemAvailable:   489424520 kB
> Buffers:            4112 kB
> Cached:            65400 kB
> SwapCached:            0 kB
> Active:           156016 kB
> Inactive:          37720 kB
> Active(anon):     128372 kB
> Inactive(anon):     7188 kB
> Active(file):      27644 kB
> Inactive(file):    30532 kB
> Unevictable:           0 kB
> Mlocked:               0 kB
> SwapTotal:       4194300 kB
> SwapFree:        4194300 kB
> Dirty:               112 kB
> Writeback:             0 kB
> AnonPages:        124356 kB
> Mapped:            53724 kB
> Shmem:             11036 kB
> KReclaimable:      93488 kB
> Slab:             599660 kB
> SReclaimable:      93488 kB
> SUnreclaim:       506172 kB
> KernelStack:       23008 kB
> PageTables:         4340 kB
> NFS_Unstable:          0 kB
> Bounce:                0 kB
> WritebackTmp:          0 kB
> CommitLimit:    250971712 kB
> Committed_AS:    1834448 kB
> VmallocTotal:   135290159040 kB
> VmallocUsed:      229284 kB
> VmallocChunk:          0 kB
> Percpu:            80896 kB
> HardwareCorrupted:     0 kB
> AnonHugePages:     43008 kB
> ShmemHugePages:        0 kB
> ShmemPmdMapped:        0 kB
> FileHugePages:         0 kB
> FilePmdMapped:         0 kB
> CmaTotal:          65536 kB
> CmaFree:           40480 kB
> HugePages_Total:       0
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:       2048 kB
> Hugetlb:               0 kB
>
> after test:
> MemTotal:       493554824 kB
> MemFree:        484492920 kB
> MemAvailable:   482801124 kB
> Buffers:           21984 kB
> Cached:           151380 kB
> SwapCached:            0 kB
> Active:           230000 kB
> Inactive:          68068 kB
> Active(anon):     130108 kB
> Inactive(anon):    13804 kB
> Active(file):      99892 kB
> Inactive(file):    54264 kB
> Unevictable:           0 kB
> Mlocked:               0 kB
> SwapTotal:       4194300 kB
> SwapFree:        4194300 kB
> Dirty:                36 kB
> Writeback:             0 kB
> AnonPages:        125080 kB
> Mapped:            55520 kB
> Shmem:             19220 kB
> KReclaimable:     246696 kB
> Slab:            5381572 kB
> SReclaimable:     246696 kB
> SUnreclaim:      5134876 kB
> KernelStack:       27360 kB
> PageTables:         4172 kB
> NFS_Unstable:          0 kB
> Bounce:                0 kB
> WritebackTmp:          0 kB
> CommitLimit:    250971712 kB
> Committed_AS:    1588600 kB
> VmallocTotal:   135290159040 kB
> VmallocUsed:      230836 kB
> VmallocChunk:          0 kB
> Percpu:          1827840 kB
> HardwareCorrupted:     0 kB
> AnonHugePages:     43008 kB
> ShmemHugePages:        0 kB
> ShmemPmdMapped:        0 kB
> FileHugePages:         0 kB
> FilePmdMapped:         0 kB
> CmaTotal:          65536 kB
> CmaFree:           40480 kB
> HugePages_Total:       0
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:       2048 kB
> Hugetlb:               0 kB
>
> after echo 3 > /proc/sys/vm/drop_caches
> MemTotal:       493554824 kB
> MemFree:        485104048 kB
> MemAvailable:   483358392 kB
> Buffers:            6168 kB
> Cached:            79904 kB
> SwapCached:            0 kB
> Active:           165348 kB
> Inactive:          45780 kB
> Active(anon):     130528 kB
> Inactive(anon):    13800 kB
> Active(file):      34820 kB
> Inactive(file):    31980 kB
> Unevictable:           0 kB
> Mlocked:               0 kB
> SwapTotal:       4194300 kB
> SwapFree:        4194300 kB
> Dirty:                 8 kB
> Writeback:             0 kB
> AnonPages:        125236 kB
> Mapped:            55516 kB
> Shmem:             19220 kB
> KReclaimable:     226332 kB
> Slab:            5353952 kB
> SReclaimable:     226332 kB
> SUnreclaim:      5127620 kB
> KernelStack:       23040 kB
> PageTables:         4212 kB
> NFS_Unstable:          0 kB
> Bounce:                0 kB
> WritebackTmp:          0 kB
> CommitLimit:    250971712 kB
> Committed_AS:    1672424 kB
> VmallocTotal:   135290159040 kB
> VmallocUsed:      230436 kB
> VmallocChunk:          0 kB
> Percpu:          1379840 kB
> HardwareCorrupted:     0 kB
> AnonHugePages:     43008 kB
> ShmemHugePages:        0 kB
> ShmemPmdMapped:        0 kB
> FileHugePages:         0 kB
> FilePmdMapped:         0 kB
> CmaTotal:          65536 kB
> CmaFree:           40480 kB
> HugePages_Total:       0
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:       2048 kB
> Hugetlb:               0 kB
>
> after test and drop caches, the /proc/cgroups is:
> #subsys_name    hierarchy       num_cgroups     enabled
> cpuset  11      1       1
> cpu     2       1       1
> cpuacct 2       1       1
> blkio   8       1       1
> memory  5       83      1
> devices 3       41      1
> freezer 6       1       1
> net_cls 9       1       1
> perf_event      10      1       1
> net_prio        9       1       1
> hugetlb 4       1       1
> pids    7       51      1
> rdma    12      1       1
>
> All the dir that created by the script is already removed, but I got:
>  - MemFree is decreased about 6.7G
>  - SUnreclaim is increased about 4.6G
>  - Percpu is increased about 1.7G
>
> It seems we have memory leak in cgroup ?