Ifihan si Semaphores ni Linux

Itumọ nkan naa ni a pese sile ni aṣalẹ ti ibẹrẹ ikẹkọ naa "Alakoso Linux.Basic".

Semaphore jẹ ẹrọ ti o fun laaye awọn ilana idije ati awọn okun lati ṣiṣẹ pẹlu awọn orisun pinpin ati ṣe iranlọwọ ni yanju ọpọlọpọ awọn iṣoro amuṣiṣẹpọ gẹgẹbi awọn ere-ije, awọn titiipa ati iwa aiṣedeede okun.

Lati yanju awọn iṣoro wọnyi, ekuro ni awọn irinṣẹ bii mutexes, semaphores, awọn ifihan agbara ati awọn idena.

Awọn oriṣi mẹta ti semaphores lo wa:

1. Semaphore alakomeji
2. Kika semaphore
3. Awọn akojọpọ Semaphore (ṣeto semaphore)

Wo Ipo IPC

Awọn aṣẹ wọnyi le ṣee lo lati gba alaye nipa ipo lọwọlọwọ ti ibaraẹnisọrọ laarin ilana (IPC).

# ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x00000000 65536 root 600 393216 2 dest
0x00000000 98305 root 600 393216 2 dest
0x00000000 131074 root 600 393216 2 dest
0x00000000 163843 root 600 393216 2 dest
0x00000000 196612 root 600 393216 2 dest
0x00000000 229381 root 600 393216 2 dest
0x00000000 262150 root 600 393216 2 dest
0x00000000 294919 root 600 393216 2 dest
0x00000000 327688 root 600 393216 2 dest
------ Semaphore Arrays --------

key semid owner perms nsems

------ Message Queues --------
key msqid owner perms used-bytes messages

Awọn akojọpọ semaphore ti nṣiṣe lọwọ

Ṣe afihan alaye nipa awọn akojọpọ semaphore ti nṣiṣe lọwọ.

# ipcs -s
------ Semaphore Arrays --------
key semid owner perms nsems

Pipin iranti apa

Wo alaye nipa awọn abala iranti pinpin ti nṣiṣe lọwọ.

# ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x00000000 65536 root 600 393216 2 dest
0x00000000 98305 root 600 393216 2 dest

Awọn ifilelẹ lọ

Egbe ipcs -l han pín iranti, semaphore ati ifiranṣẹ ifilelẹ.

# ipcs -l
------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 4194303
max total shared memory (kbytes) = 1073741824
min seg size (bytes) = 1

------ Semaphore Limits --------
max number of arrays = 128
max semaphores per array = 250
max semaphores system wide = 32000
max ops per semop call = 32
semaphore max value = 32767

------ Messages: Limits --------
max queues system wide = 16
max size of message (bytes) = 65536
default max size of queue (bytes) = 65536

Pipin iranti

Awọn pipaṣẹ ni isalẹ han awọn pín iranti.

# ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x00000000 65536 root 600 393216 2 dest
0x00000000 98305 root 600 393216 2 dest
0x00000000 131074 root 600 393216 2 dest
0x00000000 163843 root 600 393216 2 dest
0x00000000 196612 root 600 393216 2 dest
0x00000000 229381 root 600 393216 2 dest
0x00000000 262150 root 600 393216 2 dest
0x00000000 294919 root 600 393216 2 dest
0x00000000 327688 root 600 393216 2 dest

Awọn olupilẹṣẹ orisun

Aṣẹ naa ṣafihan olumulo ati ẹgbẹ ti eni ati ẹlẹda ti orisun naa.

# ipcs -m -c

------ Shared Memory Segment Creators/Owners --------
shmid perms cuid cgid uid gid
65536 600 root root root root
98305 600 root root root root
131074 600 root root root root
163843 600 root root root root
196612 600 root root root root
229381 600 root root root root
262150 600 root root root root
294919 600 root root root root
327688 600 root root root root

Lilo Awọn irinṣẹ IPC

Ni apẹẹrẹ ni isalẹ, paramita -u Ṣe afihan akopọ ti lilo gbogbo awọn irinṣẹ IPC.

# ipcs -u

------ Shared Memory Status --------
segments allocated 9
pages allocated 864
pages resident 477
pages swapped 0
Swap performance: 0 attempts 0 successes

------ Semaphore Status --------
used arrays = 0
allocated semaphores = 0

------ Messages: Status --------
allocated queues = 0
used headers = 0
used space = 0 bytes

Nigbati awọn iṣẹ ba duro, semaphores ati awọn abala iranti pinpin gbọdọ tun paarẹ. Ti wọn ko ba yọ kuro, eyi le ṣee ṣe nipa lilo aṣẹ ipcrm, ti o kọja idanimọ ohun elo IPC.

# ipcs -a
# ipcrm -s < sem id>

O tun le yi awọn opin semaphore pada nipa lilo sysctl.

# /sbin/sysctl -w kernel.sem=250

orisun: www.habr.com