[systemd-devel] [PATCH 3/3] kdbus: get some creds during meta append for optimization

Djalal Harouni tixxdz at opendz.org
Thu Aug 21 10:11:55 PDT 2014

On Wed, Aug 20, 2014 at 10:49:22PM +0200, Daniel Mack wrote:
> On 08/20/2014 06:16 PM, Djalal Harouni wrote:
> > On Tue, Aug 19, 2014 at 09:15:35AM +0200, Daniel Mack wrote:
> >> Hmm, I'm not convinced this buys us anything really. After all, that
> >> struct has a single user only, and factoring out these fields doesn't
> >> necessarily lead to more readability.
> > Hmm with your commit 7bde48f293f5, I guess we have to add a generic
> > struct like that, or split into multiple structs, the aim would be to
> > share the struct and operations that perform the:
> > 
> > Translate and install fields into the receiver's slice when requesting 
> > the connection info or when the receiver reads the message ?
> Atm, I think the best way is to fully populate the items at creation
> time, and override them again when installing the message. That way, we
> at least make sure not to deliver bogus data in for connection info
> calls at we get rid of the logical dependency between metadata and the
> queue items. A long-hanging fruit for optimization would be to check the
> namespaces at delivery time, and only patch over data if they differ.
> That can still be done later.
Yes, sounds good.

> > Well, yes without numbers the optimization for uid/gid perhaps is not
> > needed, but for the auxgroup perhaps ? we can allocate and get the
> > auxgrps one time, then just memdup the data into the queue->auxgrps[] ?
> But their not necessarily equal in size. After all, in the final item,
> all values are u64, so we have to walk the list again.
> > Just trying to figure out the best solution...
> Me too :)
> > BTW Daniel, sorry for this stupid question:
> > Can't the KDBUS_ATTACH_AUXGROUPS be part of the KDBUS_ATTACH_CREDS item?
> > 
> > Will be easy to parse it in the same item with uid/gid...
> Hmm, I don't think so. We designed the metadata thing in a way that it
> allows users to request individual items in a fine-grained way, and I'm
> not convinced that every user who wants the creds item is also
> interested in auxgrp information. The other way around, it might be
> different story though.
Ok, thank you for confirming.

> Thanks,
> Daniel

Djalal Harouni

More information about the systemd-devel mailing list