From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <52AF26C1.1060300@xenomai.org> Date: Mon, 16 Dec 2013 17:13:53 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <52AEB440.5090103@xenomai.org> <52AF2686.7010907@xenomai.org> In-Reply-To: <52AF2686.7010907@xenomai.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] rehashing List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Philippe Gerum Cc: Xenomai On 12/16/2013 05:12 PM, Philippe Gerum wrote: > On 12/16/2013 09:05 AM, Gilles Chanteperdrix wrote: >> >> Hi Philippe, >> >> looking at the registry code, I had an idea: we could increase the >> number of descriptors dynamically when they are exhausted, and increase >> the hash size as well. This would make the configurable number of slots >> a starting point, but not a liimit. The access to the registry by name >> does not really need to be fast, so we could protect it with a mutex > > The registry hash is a low contention resource, so using a dedicated > mutex is likely more efficient than grabbing the big nklock in most > cases anyway. > >> (that would mean that all services accessing the registry by name would >> need to run in secondary mode, but I am not sure we care, and if we do, >> we can use an xnsynch instead). >> >> What do you think? >> > > Recent Cobalt users of the registry put aside, this is basically about > deciding whether: > > - issuing connect() on a rtipc socket should switch the caller to > secondary mode, since other in-kernel users disappeared during the Great > Refactoring (tm). bind() does have such requirement already. > > - all present and future callers of xnregistry_remove() should run in > secondary mode as well. There is only one caller remaining so far, and > it does (i.e. thread cleanup code). sem_destroy/sem_close/sem_unlink, pthread_mutex_destroy, and pthread_cond_destroy now call xnregistry_remove. -- Gilles.