[CRIU] [PATCH v2] early_init: Force to unlimit files on early init

[Cyrill Gorcunov]

On Wed, Mar 13, 2019 at 07:49:48AM +0200, Mike Rapoport wrote:
> On Wed, Mar 13, 2019 at 12:28:51AM +0300, Cyrill Gorcunov wrote:
> > It is so because when we checkpoint containers with huge number
> > of files opened we get
> > 
> >  | (00.659733) Error (criu/util.c:403): Can't open 57950: Too many open files
> >  | (00.659741) Error (criu/proc_parse.c:2399): Can't open 57950/task on procfs: Too many open files
> >  | (00.675635) Error (criu/cr-dump.c:2111): Dumping FAILED.
> >  | Failed to checkpoint the Container
> > 
> > simply because we're opening more files for criu itself. This mostly
> > reverts a148e87469a36dc75e263259e39ed30336343fc8
> > 
> > v2:
> >  - fix typo and naming
> > 
> > Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
> 
> Reviewed-by: Mike Rapoport <rppt at linux.ibm.com>

You know, I've been talking to Andrew about this issue and the commit
I mentioned, and he propose that we simply rise limits on checkpoint
only. Which sounds reasonable. But thinking more I conclude that we
still need to rise limits early -- on both checkpoint and restore
we might need to have _more_ files than default limit: criu allocates
additional files for service fds and these additional files might
overflow the default limit if task already has opened files equal
to limit, iow when task is too eager for file descriptors.