The prlimit tool shows the soft & hard limits that apply to a process:
marc:~> prlimit -p 2569
RESOURCE DESCRIPTION SOFT HARD UNITS
AS address space limit unlimited unlimited bytes
CORE max core file size 0 unlimited blocks
CPU CPU time unlimited unlimited seconds
DATA max data size unlimited unlimited bytes
FSIZE max file size unlimited unlimited blocks
LOCKS max number of file locks held unlimited unlimited
MEMLOCK max lockedinmemory address space 65536 65536 bytes
MSGQUEUE max bytes in POSIX mqueues 819200 819200 bytes
NICE max nice prio allowed to raise 0 0
NOFILE max number of open files 1024 4096
NPROC max number of processes 4096 62905
RSS max resident set size unlimited unlimited pages
RTPRIO max realtime priority 0 0
RTTIME timeout for realtime tasks unlimited unlimited microsecs
SIGPENDING max number of pending signals 62905 62905
STACK max stack size 8388608 unlimited bytes
If we need a more parsable output to feed to some script we can use --raw:
marc:~> prlimit --raw -p 32738
RESOURCE DESCRIPTION SOFT HARD UNITS
AS addressx20spacex20limit unlimited unlimited bytes
CORE maxx20corex20filex20size 0 unlimited blocks
CPU CPUx20time unlimited unlimited seconds
DATA maxx20datax20size unlimited unlimited bytes
FSIZE maxx20filex20size unlimited unlimited blocks
LOCKS maxx20numberx20ofx20filex20locksx20held unlimited unlimited
MEMLOCK maxx20lockedinmemoryx20addressx20space 65536 65536 bytes
MSGQUEUE maxx20bytesx20inx20POSIXx20mqueues 819200 819200 bytes
NICE maxx20nicex20priox20allowedx20tox20raise 0 0
NOFILE maxx20numberx20ofx20openx20files 1024 4096
NPROC maxx20numberx20ofx20processes 62905 62905
RSS maxx20residentx20setx20size unlimited unlimited pages
RTPRIO maxx20realtimex20priority 0 0
RTTIME timeoutx20forx20realtimex20tasks unlimited unlimited microsecs
SIGPENDING maxx20numberx20ofx20pendingx20signals 62905 62905
STACK maxx20stackx20size 8388608 unlimited bytes
If we are interested in just a few parameters we can list them ...
root:~> prlimit --rss --fsize -p 32738
RESOURCE DESCRIPTION SOFT HARD UNITS
RSS max resident set size unlimited unlimited pages
FSIZE max file size unlimited unlimited blocks
If we want to chop the headings ...
root:~> prlimit --noheadings --rss --fsize -p 32738
RSS max resident set size unlimited unlimited pages
FSIZE max file size unlimited unlimited blocks
We can also change limits by specifying the limit, hard and soft limits as in the examples below:
root:~> prlimit --nofile=1024:4096 -p 32738 → set soft & hard limit
root:~> prlimit --msgqueue=:1000000 -p 29221 → set only hard limit
root:~> prlimit --nproc=2048: -p 29221 → set only soft limit
root:~> prlimit --sigpending=8192 -p 29221 → set both to the same value
root:~> prlimit --rss --locks=4096 -p 29221 → set locks limit and query rss
root:~> prlimit --rss=unlimited -p 29221 → remove limits for rss