Fampidirana ny Semaphore amin'ny Linux

Ny fandikana ny lahatsoratra dia nomanina tamin'ny fiandohan'ny fianarana "Administrator Linux.Basic".

Ny semaphore dia fomba iray ahafahan'ny dingana sy kofehy mifaninana mizara loharano ary manampy amin'ny olana amin'ny fampifanarahana isan-karazany toy ny hazakazaka, ny fiatoana (mihidy), ary ny kofehy tsy mety.

Mba hamahana ireo olana ireo, ny kernel dia manome fitaovana toy ny mutexes, semaphore, famantarana ary sakana.

Misy karazany telo ny semaphore:

1. Semaphore binary
2. Semaphores-counters (fanisana semaphore)
3. Arrays of semaphore (semaphore set)

Jereo ny satan'ny IPC

Ireto baiko manaraka ireto dia manome fampahalalana momba ny toetry ny fifandraisana eo amin'ny dingana (IPC) ankehitriny.

# 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

Fikirakirana mavitrika amin'ny semaphore

Asehoy ny fampahalalana momba ny semaphore mavitrika.

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

Fizarana fahatsiarovana iombonana

Jereo ny fampahafantarana momba ny fizarana fahatsiarovana zaraina mavitrika.

# 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

fetra

ekipa ipcs -l mampiseho fahatsiarovana iombonana, semaphore ary fetran'ny hafatra.

# 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

Fahatsiarovana iombonana

Ny baiko etsy ambany dia mampiseho ny fahatsiarovana iombonana.

# 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

Mpamorona loharanon-karena

Ny baiko dia mampiseho ny mpampiasa sy ny vondron'ny tompony sy ny mpamorona ny loharano.

# 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

Mampiasa fitaovana IPC

Ao amin'ny ohatra etsy ambany, ny parameter -u mampiseho famintinana ny fampiasana ny fitaovana IPC rehetra.

# 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

Rehefa mijanona ny serivisy dia tsy maintsy esorina koa ny semaphore sy ny fizarana fahatsiarovana iombonana. Raha tsy nesorina izy ireo, dia azo atao izany amin'ny alàlan'ny baiko ipcrm, mandalo ny famantarana ny zavatra IPC.

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

Azonao atao koa ny manova ny fetran'ny semaphore amin'ny fampiasana sysctl.

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

Source: www.habr.com