Re: [PATCH 2/8] rhashtable: remove nulls_base and related code.

Herbert Xu
2018-05-05T09:12:15Z

On Fri, May 04, 2018 at 01:54:14PM +1000, NeilBrown wrote:
> This "feature" is unused, undocumented, and untested and so
> doesn't really belong. If a use for the nulls marker
> is found, all this code would need to be reviewed to
> ensure it works as required. It would be just as easy to
> just add the code if/when it is needed instead.
>
> This patch actually fixes a bug too. The table resizing allows a
> table to grow to 2^31 buckets, but the hash is truncated to 27 bits -
> any growth beyond 2^27 is wasteful an ineffective.
>
> This patch result in NULLS_MARKER(0) being used for all chains,
> and leave the use of rht_is_a_null() to test for it.
>
> Signed-off-by: NeilBrown <neilb@suse.com>

I disagree. This is a fundamental requirement for the use of
rhashtable in certain networking systems such as TCP/UDP. So
we know that there will be a use for this.

As to the bug fix, please separate it out of the patch and resubmit.

Thanks,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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