Re: [PATCH net-next 3/3] nftables: Convert nft_hash to use generic rhashtable

On 1. August 2014 11:39:01 GMT+01:00, Thomas Graf [off-list ref] wrote:

On 08/01/14 at 11:17am, Patrick McHardy wrote:

quoted

On 1. August 2014 09:52:00 GMT+01:00, Thomas Graf [off-list ref]

wrote:

quoted

quoted

If the set size is known in advance, the table is sized accordingly,
otherwise the table size will default to 64. This is a slight change
in behaviour as previously the default was 4 which eventually

required

quoted

quoted

many expansion iterations.

That's assuming a sufficient number of entries will be added. I think

there

quoted

will be many cases in nftables where the number will be lower. Since
expansion is not very expansive this number was chosen very

deliberately

quoted

and I'd prefer to keep it.

Other than that:

Acked-by: Patrick McHardy <redacted>

OK, I will change the nft_hash default size back to 4.

Thanks.

I think the expansion is more expensive than it looks though as we
are potentially calling synchronize_rcu() multiple times while
holding a mutex to protect from concurrent mutations.

True. On average it should only be a single grace period though IIRC.