2002-02-25 21:38:02

by Badari Pulavarty

Subject: SHM_LOCK question

Hi,

I am trying to understand how SHM_LOCK works on 2.4.17.
All I can see SHM_LOCKED set in shm_flags. I don't see how
it is locking the pages (that are already existing or future
pages). Can somebody explain ?

Any help is appreciated.

Thanks,
Badari

2002-02-26 13:47:02

by Christoph Rohland

Subject: Re: SHM_LOCK question

Hi Badari,

On Mon, 25 Feb 2002, Badari Pulavarty wrote:
> I am trying to understand how SHM_LOCK works on 2.4.17.
> All I can see SHM_LOCKED set in shm_flags. I don't see how
> it is locking the pages (that are already existing or future
> pages). Can somebody explain ?

This flag prevents that the pages are written to swap. shmem_writepage
honors it. SHM_LOCK does _not_ force actually swapped out pages into
memory though.

Greetings
Christoph