From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: Fwd: [PATCH] [-mm] ACPI: export ACPI events via netlink Date: Fri, 29 Jun 2007 15:12:38 +0200 Message-ID: <46850546.1050606@trash.net> References: <1179827251.7707.29.camel@localhost.localdomain> <1179831825.4121.30.camel@localhost> <1180258853.7707.53.camel@localhost.localdomain> <4466a10705270629h31977813hd2fc8330bcd87f78@mail.gmail.com> <4466a10705270634j3560c9a3j9c3630ddc20a24aa@mail.gmail.com> <1181811576.5411.27.camel@localhost.localdomain> <1181820510.4091.9.camel@localhost> <1181869285.5411.39.camel@localhost.localdomain> <1182178882.4063.11.camel@localhost> <1182223964.5411.76.camel@localhost.localdomain> <1182811210.6644.22.camel@johannes.berg> <1182986681.5155.55.camel@localhost> <1183023939.4769.76.camel@johannes.berg> <4684F25B.5090607@trash.net> <1183121180.4089.51.camel@johannes.berg> <4684FF9A.10807@trash.net> <1183122172.5188.24.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: Johannes Berg , Zhang Rui , netdev@vger.kernel.org, "linux-acpi@vger" , lenb@kernel.org, Thomas Graf To: hadi@cyberus.ca Return-path: In-Reply-To: <1183122172.5188.24.camel@localhost> Sender: linux-acpi-owner@vger.kernel.org List-Id: netdev.vger.kernel.org jamal wrote: > On Fri, 2007-29-06 at 14:48 +0200, Patrick McHardy wrote: > >>Johannes Berg wrote: > > >>>Hmm, another thought: since we have 32 bits for group numbers and 16 >>>bits for families we could just reserve 16 bits for groups within each >>>family. Or do we get trouble with that because in some place there's a >>>group bitmap or such? >> >> >>Yes, af_netlink has a bitmap per socket that is subscribed to any group. > > > > I think this is the challenge. The groups belong to a global namespace. > i.e when you do a socket bind to group - it is unique regardless of the > family. > Our philosophy in genetlink is to have dynamic resources allocated and > released - remember the real reason we even have this is because we were > running out of numbers ;-> That was more of a rumour :) We have 2^32-1 groups and I think 256 families, of which about 20 are used. > So while the static allocation of 16 bits per group will work (famous > last words "noone will ever need more than 640K of RAM";->) it will be > cleaner imo to allow dynamic allocation/release. > Maybe a mix (of a few static and mostly dynamic) as Patrick says - but > that would mean more coding for you ;-> Actually i like the idea of at > least your ID being your static mcast group and the rest are in the > dynamic pool (Hey, thanks Patrick;->). This means the first 2^16 are > static/reserved and if you want more groups, you register for them. I wouldn't reserve any, just hand them out as needed. Otherwise we'll run into problems with the af_netlink bitmaps.