[dm-devel] Re: [Q] don't allow tmpfs to page out

[christophe.varoqui at free.fr]

Selon Arjan van de Ven <arjanv at redhat.com>:

> 
> On Thu, Jul 15, 2004 at 09:58:37AM +0200, christophe.varoqui at free.fr wrote:
> > > 
> > > just do 
> > > mount -t ramfs none /mnt/point
> > > 
> > Would that be a suitable solution to store callout binaries for daemons
> like
> > multipathd that need to work in case of system-disk outage (/bin & swap on
> SAN
> > for example) ?
> 
> somewhat, as long as ALL requirements are there, including all libraries ;)
> 
ok, sure.
klibc linked static binaries in my case (scsi_id & multipath), so it should be ok.

> > If so, is it possible and/or correct for the daemon to do a private ramfs
> mount
> > for this purpose ?
> 
> sure; namespaces can do a LOT

Somehow "man 2 mount" is not so verbose about that "lot" :)
Can you feed a pointer to a doc explaining how to achieve such privacy ?

> > 
> > And while I'm at throwing all the questions I have on my mind :
> > * how can I disable on-demand loading for the daemon ?
> > * does mlockall() provides all the necessary garanties ?
> 
> mlockall does not guarantee that syscalls you do don't cause memory
> allocations, nor does the ramfs approach.
> 
mmm ... more questions than I had before :)
any hint about how to solve this issue ?

regards,
cvaroqui


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