Re: rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation

Thomas Graf
2015-12-07T15:35:32Z

On 12/05/15 at 03:06pm, Herbert Xu wrote:
> On Fri, Dec 04, 2015 at 07:15:55PM +0100, Phil Sutter wrote:
> >
> > > Only one should really do this, while others are waiting.
> >
> > Sure, that was my previous understanding of how this thing works.
>
> Yes that's clearly how it should be. Unfortunately while adding
> the locking to do this, I found out that you can't actually call
> __vmalloc with BH disabled so this is a no-go.
>
> Unless we can make __vmalloc work with BH disabled, I guess we'll
> have to go back to multi-level lookups unless someone has a better
> suggestion.

Thanks for fixing the race.

As for the remaining problem, I think we'll have to find a way to
serve a hard pounding user if we want to convert TCP hashtables
later on.

Did you look into what __vmalloc prevents to work with BH disabled?