Re: [PATCH 2/6] lib/rhashtable: guarantee initial hashtable allocation

[Davidlohr Bueso]

On Mon, 28 May 2018, Herbert Xu wrote:
> > +	/*
> > +	 * This is api initialization and thus we need to guarantee the
> > +	 * initial rhashtable allocation. Upon failure, retry with a
> > +	 * smallest possible size, otherwise we exhaust our options with
> > +	 * __GFP_NOFAIL.
> > +	 */
> >  	tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
> > -	if (tbl == NULL)
> > -		return -ENOMEM;
> > +	if (unlikely(tbl == NULL)) {
> > +		size = HASH_MIN_SIZE;
> > +
> > +		tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
> > +		if (tbl == NULL)
> > +			tbl = bucket_table_alloc_retry(ht, size, GFP_KERNEL);
> > +	}
>
> Perhaps you should also explain here why we don't just try the
> minimum size with __GFP_NOFAIL as the second step rather than the
> third.

Please see the comment above, I try to explain the rationale.

Thanks,
Davidlohr