Hi,
nobody an idea? I had another system today:
# cat /proc/meminfo
MemTotal: 131911684 kB
MemFree: 25734836 kB
MemAvailable: 78158816 kB
Buffers: 2916 kB
Cached: 20650184 kB
SwapCached: 544016 kB
Active: 58999352 kB
Inactive: 10084060 kB
Active(anon): 43412532 kB
Inactive(anon): 5583220 kB
Active(file): 15586820 kB
Inactive(file): 4500840 kB
Unevictable: 35032 kB
Mlocked: 35032 kB
SwapTotal: 3905532 kB
SwapFree: 0 kB
Dirty: 1048 kB
Writeback: 20144 kB
AnonPages: 47923392 kB
Mapped: 775376 kB
Shmem: 561420 kB
Slab: 35798052 kB
SReclaimable: 34309112 kB
SUnreclaim: 1488940 kB
KernelStack: 42160 kB
PageTables: 248008 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 69861372 kB
Committed_AS: 100328892 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 0 kB
VmallocChunk: 0 kB
HardwareCorrupted: 0 kB
AnonHugePages: 19177472 kB
ShmemHugePages: 0 kB
ShmemPmdMapped: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 951376 kB
DirectMap2M: 87015424 kB
DirectMap1G: 48234496 kB
# cat /proc/buddyinfo
Node 0, zone DMA 1 0 0 0 2 1 1
0 1 1 3
Node 0, zone DMA32 372 418 403 395 371 322 262
179 114 0 0
Node 0, zone Normal 89147 96397 76496 56407 41671 29289 18142
10278 4075 0 0
Node 1, zone Normal 113266 0 1 1 1 1 1
1 1 0 0
But with high PSI / memory pressure values above 10-30.
Greets,
Stefan
Am 27.03.19 um 11:56 schrieb Stefan Priebe - Profihost AG:
> Hello list,
>
> i hope this is the right place to ask. If not i would be happy to point
> me to something else.
>
> I'm seeing the following behaviour on some of our hosts running a SLES
> 15 kernel (kernel v4.12 as it's base) but i don't think it's related to
> the kernel.
>
> At some "random" interval - mostly 3-6 weeks of uptime. Suddenly mem
> pressure rises and the linux cache (Cached: /proc/meminfo) drops from
> 12G to 3G. After that io pressure rises most probably due to low cache.
> But at the same time i've MemFree und MemAvailable at 19-22G.
>
> Why does this happen? How can i debug this situation? I would expect
> that the page / file cache never drops if there is so much free mem.
>
> Thanks a lot for your help.
>
> Greets,
> Stefan
>
> Not sure whether needed but these are the vm. kernel settings:
> vm.admin_reserve_kbytes = 8192
> vm.block_dump = 0
> vm.compact_unevictable_allowed = 1
> vm.dirty_background_bytes = 0
> vm.dirty_background_ratio = 10
> vm.dirty_bytes = 0
> vm.dirty_expire_centisecs = 3000
> vm.dirty_ratio = 20
> vm.dirty_writeback_centisecs = 500
> vm.dirtytime_expire_seconds = 43200
> vm.drop_caches = 0
> vm.extfrag_threshold = 500
> vm.hugepages_treat_as_movable = 0
> vm.hugetlb_shm_group = 0
> vm.laptop_mode = 0
> vm.legacy_va_layout = 0
> vm.lowmem_reserve_ratio = 256 256 32 1
> vm.max_map_count = 65530
> vm.memory_failure_early_kill = 0
> vm.memory_failure_recovery = 1
> vm.min_free_kbytes = 393216
> vm.min_slab_ratio = 5
> vm.min_unmapped_ratio = 1
> vm.mmap_min_addr = 65536
> vm.mmap_rnd_bits = 28
> vm.mmap_rnd_compat_bits = 8
> vm.nr_hugepages = 0
> vm.nr_hugepages_mempolicy = 0
> vm.nr_overcommit_hugepages = 0
> vm.nr_pdflush_threads = 0
> vm.numa_zonelist_order = default
> vm.oom_dump_tasks = 1
> vm.oom_kill_allocating_task = 0
> vm.overcommit_kbytes = 0
> vm.overcommit_memory = 0
> vm.overcommit_ratio = 50
> vm.page-cluster = 3
> vm.panic_on_oom = 0
> vm.percpu_pagelist_fraction = 0
> vm.stat_interval = 1
> vm.swappiness = 50
> vm.user_reserve_kbytes = 131072
> vm.vfs_cache_pressure = 100
> vm.watermark_scale_factor = 10
> vm.zone_reclaim_mode = 0
>
