Re: [PATCH 01/16] PCI/P2PDMA: Pass gfp_mask flags to upstream_bridge_distance_warn()

[John Hubbard]

On 5/3/21 11:20 AM, Logan Gunthorpe wrote:
...
> > That's the thing: memory failure should be exceedingly rare for this.
> > Therefore, just fail out entirely (which I don't expect we'll likely
> > ever see), instead of doing all this weird stuff to try to continue
> > on if you cannot allocate a single page. If you are in that case, the
> > system is not in a state that is going to run your dma p2p setup well
> > anyway.
> >
> > I think it's *less* complexity to allocate up front, fail early if
> > allocation fails, and then not have to deal with these really odd
> > quirks at the lower levels.
>
> I don't see how it's all that weird. We're skipping a warning if we
> can't allocate memory to calculate part of the message. It's really not
> necessary. If the memory really can't be allocated then something else
> will fail, but we really don't need to fail here because we couldn't
> print a verbose warning message.

Well, I really dislike the result we have in this particular patch, but
I won't stand in the way of progress if that's how you really are going
to do it.

thanks,
--
John Hubbard
NVIDIA