memory reclamation and kill -9

[Ed Loehr]

When a program is killed with SIGKILL, is the non-shared memory used by that process always immediately reclaimed by the kernel? If not, what determines whether or not such memory is reclaimed by the kernel?

Thanks.

Ed

[Alex Lavrov. · Accepted solution]

The non shared memory is reclaimed, but be aware of zombies. If the process becomes zombie for some reason (bad programming or crash of the father process for example), then the memory is not reclaimed as long as zombie process exists.

In the case all goes smooth and you don't see the PID in the "ps -ef" anymore, you can be pretty sure the the non-shared memory was released.

[lawrenzo]

If you need to find out any zombie processthe command # top will sow this.

see

# man top

HTH

[Alex Lavrov.]

Another way to find them (zombies):

ps -ef | grep defunct

they will show up as processes.

[Steven E. Protter]

One sure way to get rid of zombies.

Reboot.

kill -9 rarely works.

kill -9 can create zombies if you direct it at say the middle generation of a process that has a parent and a child.

As far as shared memory goes ipcrm -m or -s depending on the type you want released will sometimes help.

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