proc_pid_status - CS50 Manual Pages

/proc/pid/status

Provides much of the information in /proc/pid/stat and /proc/pid/statm in a format that's easier for humans to parse. Here's an example:

$ cat /proc/$$/status
Name:   bash
Umask:  0022
State:  S (sleeping)
Tgid:   17248
Ngid:   0
Pid:    17248
PPid:   17200
TracerPid:      0
Uid:    1000    1000    1000    1000
Gid:    100     100     100     100
FDSize: 256
Groups: 16 33 100
NStgid: 17248
NSpid:  17248
NSpgid: 17248
NSsid:  17200
VmPeak:	  131168 kB
VmSize:	  131168 kB
VmLck:	       0 kB
VmPin:	       0 kB
VmHWM:	   13484 kB
VmRSS:	   13484 kB
RssAnon:	   10264 kB
RssFile:	    3220 kB
RssShmem:	       0 kB
VmData:	   10332 kB
VmStk:	     136 kB
VmExe:	     992 kB
VmLib:	    2104 kB
VmPTE:	      76 kB
VmPMD:	      12 kB
VmSwap:	       0 kB
HugetlbPages:          0 kB		# 4.4
CoreDumping:	0                       # 4.15
Threads:        1
SigQ:   0/3067
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000010000
SigIgn: 0000000000384004
SigCgt: 000000004b813efb
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: ffffffffffffffff
CapAmb:	0000000000000000
NoNewPrivs:     0
Seccomp:        0
Seccomp_filters:        0
Speculation_Store_Bypass:       vulnerable
Cpus_allowed:   00000001
Cpus_allowed_list:      0
Mems_allowed:   1
Mems_allowed_list:      0
voluntary_ctxt_switches:        150
nonvoluntary_ctxt_switches:     545

The fields are as follows:

Name: Command run by this process. Strings longer than TASK_COMM_LEN (16) characters (including the terminating null byte) are silently truncated.
Umask: Process umask, expressed in octal with a leading zero; see umask(2). (Since Linux 4.7.)
State: Current state of the process. One of "R (running)", "S (sleeping)", "D (disk sleep)", "T (stopped)", "t (tracing stop)", "Z (zombie)", or "X (dead)".
Tgid: Thread group ID (i.e., Process ID).
Ngid: NUMA group ID (0 if none; since Linux 3.13).
Pid: Thread ID (see gettid(2)).
PPid: PID of parent process.
TracerPid: PID of process tracing this process (0 if not being traced).
Uid Gid: Real, effective, saved set, and filesystem UIDs (GIDs).
FDSize: Number of file descriptor slots currently allocated.
Groups: Supplementary group list.
NStgid: Thread group ID (i.e., PID) in each of the PID namespaces of which pid is a member. The leftmost entry shows the value with respect to the PID namespace of the process that mounted this procfs (or the root namespace if mounted by the kernel), followed by the value in successively nested inner namespaces. (Since Linux 4.1.)
NSpid: Thread ID in each of the PID namespaces of which pid is a member. The fields are ordered as for NStgid. (Since Linux 4.1.)
NSpgid: Process group ID in each of the PID namespaces of which pid is a member. The fields are ordered as for NStgid. (Since Linux 4.1.)
NSsid: descendant namespace session ID hierarchy Session ID in each of the PID namespaces of which pid is a member. The fields are ordered as for NStgid. (Since Linux 4.1.)
VmPeak: Peak virtual memory size.
VmSize: Virtual memory size.
VmLck: Locked memory size (see mlock(2)).
VmPin: Pinned memory size (since Linux 3.2). These are pages that can't be moved because something needs to directly access physical memory.
VmHWM: Peak resident set size ("high water mark"). This value is inaccurate; see /proc/pid/statm above.
VmRSS: Resident set size. Note that the value here is the sum of RssAnon, RssFile, and RssShmem. This value is inaccurate; see /proc/pid/statm above.
RssAnon: Size of resident anonymous memory. (since Linux 4.5). This value is inaccurate; see /proc/pid/statm above.
RssFile: Size of resident file mappings. (since Linux 4.5). This value is inaccurate; see /proc/pid/statm above.
RssShmem: Size of resident shared memory (includes System V shared memory, mappings from tmpfs(5), and shared anonymous mappings). (since Linux 4.5).
VmData VmStk VmExe: Size of data, stack, and text segments. This value is inaccurate; see /proc/pid/statm above.
VmLib: Shared library code size.
VmPTE: Page table entries size (since Linux 2.6.10).
VmPMD: Size of second-level page tables (added in Linux 4.0; removed in Linux 4.15).
VmSwap: Swapped-out virtual memory size by anonymous private pages; shmem swap usage is not included (since Linux 2.6.34). This value is inaccurate; see /proc/pid/statm above.
HugetlbPages: Size of hugetlb memory portions (since Linux 4.4).
CoreDumping: Contains the value 1 if the process is currently dumping core, and 0 if it is not (since Linux 4.15). This information can be used by a monitoring process to avoid killing a process that is currently dumping core, which could result in a corrupted core dump file.
Threads: Number of threads in process containing this thread.
SigQ: This field contains two slash-separated numbers that relate to queued signals for the real user ID of this process. The first of these is the number of currently queued signals for this real user ID, and the second is the resource limit on the number of queued signals for this process (see the description of RLIMIT_SIGPENDING in getrlimit(2)).
SigPnd ShdPnd: Mask (expressed in hexadecimal) of signals pending for thread and for process as a whole (see pthreads(7) and signal(7)).
SigBlk SigIgn SigCgt: Masks (expressed in hexadecimal) indicating signals being blocked, ignored, and caught (see signal(7)).
CapInh CapPrm CapEff: Masks (expressed in hexadecimal) of capabilities enabled in inheritable, permitted, and effective sets (see capabilities(7)).
CapBnd: Capability bounding set, expressed in hexadecimal (since Linux 2.6.26, see capabilities(7)).
CapAmb: Ambient capability set, expressed in hexadecimal (since Linux 4.3, see capabilities(7)).
NoNewPrivs: Value of the no_new_privs bit (since Linux 4.10, see prctl(2)).
Seccomp: Seccomp mode of the process (since Linux 3.8, see seccomp(2)). 0 means SECCOMP_MODE_DISABLED; 1 means SECCOMP_MODE_STRICT; 2 means SECCOMP_MODE_FILTER. This field is provided only if the kernel was built with the CONFIG_SECCOMP kernel configuration option enabled.
Seccomp_filters: Number of seccomp filters attached to the process (since Linux 5.9, see seccomp(2)).
Speculation_Store_Bypass: Speculation flaw mitigation state (since Linux 4.17, see prctl(2)).
Cpus_allowed: Hexadecimal mask of CPUs on which this process may run (since Linux 2.6.24, see cpuset(7)).
Cpus_allowed_list: Same as previous, but in "list format" (since Linux 2.6.26, see cpuset(7)).
Mems_allowed: Mask of memory nodes allowed to this process (since Linux 2.6.24, see cpuset(7)).
Mems_allowed_list: Same as previous, but in "list format" (since Linux 2.6.26, see cpuset(7)).
voluntary_ctxt_switches nonvoluntary_ctxt_switches: Number of voluntary and involuntary context switches (since Linux 2.6.23).

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