[Devel] Re: [RFC][PATCH] Do not set /proc inode->pid for non-pid-related inodes

[Eric W. Biederman]

Dave Hansen <hansendc at us.ibm.com> writes:

> On Mon, 2007-03-26 at 11:12 -0600, Eric W. Biederman wrote:
>> 
>> > In (at least one version of) Dave's patches, the /proc your pidns is
>> > automatically used when you use /proc.  In that case a /proc should
>> > just go away when the last task goes away, since noone else can use
>> > that /proc.
>> 
>> Unless I am rather confused that does extremely nasty things to
>> the VFS dentry cache.  Because a dentry can point at one process
>> one minute and another process the next.  It is doable but only
>> at the cost of decreased performance.
>
> By using, I think Serge meant "mounting".  We're going to statically
> assign a /proc mount to a namespace when the mount is created, not fudge
> it around at runtime.

I think Serge misread that.  He specifically talked about not having
to remount /proc.  Therefore I believe he understood it did something
at runtime.

> How does this thrash the dcache?

Fudging at runtime is horrible.

Caching the pid_mnt in the pid_namespace appears fine, as long as
we get the reference counting correct.

Eric
_______________________________________________
Containers mailing list
Containers at lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/containers