Andy Zhou <[email protected]> wrote on 03/16/2016 01:20:48 PM: > From: Andy Zhou <[email protected]> > To: Ryan Moats/Omaha/IBM@IBMUS > Cc: ovs dev <[email protected]> > Date: 03/16/2016 01:31 PM > Subject: Re: [ovs-dev] [ovs-dev, ovsdb-server, multithreading, RFC, > 1/9] ovsdb: Do not group sessions by remote. > > On Wed, Mar 16, 2016 at 10:38 AM, Ryan Moats <[email protected]> wrote: > > ---- Original Message ---- > > Currently ovsdb_jsonrpc_session are grouped together in a linked > > list within 'ovsdb_jsonrpc_remote'. This makes sense since most > > session operations applies to sessions within a remote. > > > > However, in order to scale up ovsdb-server with multi-threading, it is > > more convenient to distribute a sessions to any thread available, > > regardless which remote it is associated with. > > > > This patch introduces a set of APIs that provide operations on > > a list of sessions. Instead of group sessions by remote, they > > are linked together in a new ovs_list field 'all_sessions' in the > > ovsdb_jsonrpc_server struct. > > > > With multi-threading, the design is that all sessions managed > > by a thread will have them linked together on a thread private > > linked list. At that time, the 'all_sessions' field in > > ovsdb_jsonrpc_server struct will have all session managed > > the main process. > > > > Signed-off-by: Andy Zhou <[email protected]> > > I've given this patch a bit of a test spin and while it appears > relatively sane for simple cases, I'm concerned that the patch > should be using LIST_FOR_EACH_SAFE in more places than it currently > does. The code snippet that got me wondering was the use of > LIST_FOR_EACH in ovsdb_jsonrpc_sessions_count()...\ > > Thanks for testing it. > > LIST_FOR_EACH_SAFE is required to protect against possible list elements > removal during the list traversal. Since a session is always > assigned to a single thread, > I don't see how it can be remove from the list during the > ovsdb_jsonprc_session_count(), > Or I am still missing something here.
I'm probably misreading, but I read the all_sessions list as being accessible by all threads. That means I have to worry about thread 1 removing a session from all_sessions while thread 2 is within sessions_count. Ryan (regXboi) _______________________________________________ dev mailing list [email protected] http://openvswitch.org/mailman/listinfo/dev
