On my laptop running openSUSE Leap 15.4 swap usage keeps growing, until after
several days processes are killed by the OOM killer.

Swap usage isn't going down significantly even after stopping most use
processes.

After a reboot the same pattern is shown: swap usage is going up again.

After 3 days running, I'm seeing 2.5GB swap used:

# free
              total        used        free      shared  buff/cache   available
Mem:       32476508    28181440      749956    22399648    26361408     4295068
Swap:      33554428     2566144    30988284

# cat /proc/meminfo
MemTotal:       32476508 kB
MemFree:          764712 kB
MemAvailable:    4309652 kB
Buffers:             748 kB
Cached:         25370992 kB
SwapCached:        10000 kB
Active:          3887988 kB
Inactive:       25143556 kB
Active(anon):    1726396 kB
Inactive(anon): 24281868 kB
Active(file):    2161592 kB
Inactive(file):   861688 kB
Unevictable:      778528 kB
Mlocked:           13880 kB
SwapTotal:      33554428 kB
SwapFree:       30988284 kB
Dirty:              6120 kB
Writeback:             0 kB
AnonPages:       4375308 kB
Mapped:           536888 kB
Shmem:          22399772 kB
KReclaimable:     989620 kB
Slab:            1231732 kB
SReclaimable:     989620 kB
SUnreclaim:       242112 kB
KernelStack:       22832 kB
PageTables:        99672 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:    49792680 kB
Committed_AS:   36645776 kB
VmallocTotal:   34359738367 kB
VmallocUsed:       67064 kB
VmallocChunk:          0 kB
Percpu:             7296 kB
HardwareCorrupted:     0 kB
AnonHugePages:   1413120 kB
ShmemHugePages:        0 kB
ShmemPmdMapped:        0 kB
FileHugePages:         0 kB
FilePmdMapped:         0 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
Hugetlb:               0 kB
DirectMap4k:     1328552 kB
DirectMap2M:    30789632 kB
DirectMap1G:     1048576 kB

# uname -a
Linux jglap 5.14.21-150400.24.21-default #1 SMP PREEMPT_DYNAMIC Wed Sep 7
06:51:18 UTC 2022 (974d0aa) x86_64 x86_64 x86_64 GNU/Linux

# df -k | grep tmpfs
devtmpfs             4096         0       4096   0% /dev
tmpfs            16238252     11580   16226672   1% /dev/shm
tmpfs             6495304     35264    6460040   1% /run
tmpfs                4096         0       4096   0% /sys/fs/cgroup
tmpfs             3247648       140    3247508   1% /run/user/1000

# ipcs -m
------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status      
0x00000000 28         gross      600        393216     2          dest         
0x00000000 31         gross      600        524288     2          dest         
0x00000000 32         gross      600        393216     2          dest         
0x00000000 35         gross      600        524288     2          dest         
0x00000000 38         gross      600        524288     2          dest         
0x00000000 41         gross      600        524288     2          dest

Summing up different values of all processes from /proc/<pid>/smaps_rollup show
much lower swap usage:

Swap:       116900 KB
Pss_Shmem:   51861 KB
SwapPss:     96114 KB