Re: Memory mapped files question

Frank van Maarseveen (frankvm@xs4all.nl)
Mon, 14 Apr 2003 22:27:41 +0200

On Mon, Apr 14, 2003 at 04:13:52PM -0400, Richard B. Johnson wrote:
>
> Memory mapped files are supposed to be accessed through memory!
> Any program that needs to know what's on the physical disk is
> broken. If you need to write to files and know when they are
> written to the physical media, you use a journaled file-system.

It is not that simple.
Shared mmaped files are _never_ flushed, at least in 2.4.x. So,
without an explicit msync() a process (innd comes to mind) may loose
years of updates upon a system crash or power outage.

I have learned to live with it but I still find this a bit awkward.

-- 
Frank
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/