On Wed, May 27, 2020 at 06:46:06PM +0800, Feng Tang wrote: > Hi Qian, > > On Tue, May 26, 2020 at 10:25:39PM -0400, Qian Cai wrote: > > > > > > [1] https://lkml.org/lkml/2020/3/5/57 > > > > > > > > > > Reverted this series fixed a warning under memory pressue. > > > > > > > > Andrew, Stephen, can you drop this series? > > > > > > > > > > > > > > [ 3319.257898] LTP: starting oom01 > > > > > [ 3319.284417] ------------[ cut here ]------------ > > > > > [ 3319.284439] memory commitment underflow > > > > > > Thanks for the catch! > > > > > > Could you share the info about the platform, like the CPU numbers > > > and RAM size, and what's the mmap test size of your test program. > > > It would be great if you can point me the link to the test program. > > > > I have been reproduced this on both AMD and Intel. The test just > > allocating memory and swapping. > > > > https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/oom/oom01.c > > https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/tunable/overcommit_memory.c > > > > It might be better to run the whole LTP mm tests if none of the above > > triggers it for you which has quite a few memory pressurers. > > > > /opt/ltp/runltp -f mm > > Thanks for sharing. I tried to reproduce this on 2 server plaforms, > but can't reproduce it, and they are still under testing. > > Meanwhile, could you help to try the below patch, which is based on > Andi's suggestion and have some debug info. The warning is a little > strange, as the condition is > > (percpu_counter_read(&vm_committed_as) < > -(s64)vm_committed_as_batch * num_online_cpus()) > > while for your platform (48 CPU + 128 GB RAM), the > '-(s64)vm_committed_as_batch * num_online_cpus()' > is a s64 value: '-32G', which makes the condition hard to be true, > and when it is, it could be triggered by some magic for s32/s64 > operations around the percpu-counter. Here is the information on AMD and powerpc below affected by this. It could need a bit patient to reproduce, but our usual daily CI would trigger it eventually after a few tries. # git clone https://github.com/cailca/linux-mm.git # cd linux-mm # ./compile.sh # systemctl reboot # ./test.sh == AMD == # lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 128 On-line CPU(s) list: 0-127 Thread(s) per core: 2 Core(s) per socket: 32 Socket(s): 2 NUMA node(s): 8 Vendor ID: AuthenticAMD CPU family: 23 Model: 1 Model name: AMD EPYC 7601 32-Core Processor Stepping: 2 CPU MHz: 3184.974 CPU max MHz: 2200.0000 CPU min MHz: 1200.0000 BogoMIPS: 4391.87 Virtualization: AMD-V L1d cache: 32K L1i cache: 64K L2 cache: 512K L3 cache: 8192K NUMA node0 CPU(s): 0-7,64-71 NUMA node1 CPU(s): 8-15,72-79 NUMA node2 CPU(s): 16-23,80-87 NUMA node3 CPU(s): 24-31,88-95 NUMA node4 CPU(s): 32-39,96-103 NUMA node5 CPU(s): 40-47,104-111 NUMA node6 CPU(s): 48-55,112-119 NUMA node7 CPU(s): 56-63,120-127 # numactl -H available: 8 nodes (0-7) node 0 cpus: 0 1 2 3 4 5 6 7 64 65 66 67 68 69 70 71 node 0 size: 20028 MB node 0 free: 3837 MB node 1 cpus: 8 9 10 11 12 13 14 15 72 73 74 75 76 77 78 79 node 1 size: 0 MB node 1 free: 0 MB node 2 cpus: 16 17 18 19 20 21 22 23 80 81 82 83 84 85 86 87 node 2 size: 0 MB node 2 free: 0 MB node 3 cpus: 24 25 26 27 28 29 30 31 88 89 90 91 92 93 94 95 node 3 size: 0 MB node 3 free: 0 MB node 4 cpus: 32 33 34 35 36 37 38 39 96 97 98 99 100 101 102 103 node 4 size: 31391 MB node 4 free: 21309 MB node 5 cpus: 40 41 42 43 44 45 46 47 104 105 106 107 108 109 110 111 node 5 size: 0 MB node 5 free: 0 MB node 6 cpus: 48 49 50 51 52 53 54 55 112 113 114 115 116 117 118 119 node 6 size: 0 MB node 6 free: 0 MB node 7 cpus: 56 57 58 59 60 61 62 63 120 121 122 123 124 125 126 127 node 7 size: 0 MB node 7 free: 0 MB node distances: node 0 1 2 3 4 5 6 7 0: 10 16 16 16 32 32 32 32 1: 16 10 16 16 32 32 32 32 2: 16 16 10 16 32 32 32 32 3: 16 16 16 10 32 32 32 32 4: 32 32 32 32 10 16 16 16 5: 32 32 32 32 16 10 16 16 6: 32 32 32 32 16 16 10 16 7: 32 32 32 32 16 16 16 10 == powerpc == # lscpu Architecture: ppc64le Byte Order: Little Endian CPU(s): 128 On-line CPU(s) list: 0-127 Thread(s) per core: 4 Core(s) per socket: 16 Socket(s): 2 NUMA node(s): 2 Model: 2.2 (pvr 004e 1202) Model name: POWER9 (raw), altivec supported CPU max MHz: 3800.0000 CPU min MHz: 2300.0000 L1d cache: 32K L1i cache: 32K L2 cache: 512K L3 cache: 10240K NUMA node0 CPU(s): 0-63 NUMA node8 CPU(s): 64-127 # numactl -H available: 2 nodes (0,8) node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 node 0 size: 130138 MB node 0 free: 125654 MB node 8 cpus: 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 node 8 size: 130781 MB node 8 free: 124756 MB node distances: node 0 8 0: 10 40 8: 40 10
