Re: pcp updates: libpcp locking and concurrency control changes

Frank,

Just a small point I noticed on re-reading an earlier response from you.

On 16/01/17 11:49, Frank Ch. Eigler wrote:
> ...
>>     [...] Additionally the lock ordering of the new local mutexes
>>     and __pmLock_extcall ensures these ones are deadlock free.
> 
> Yeah, this is simple to show because "__pmLock_extcall" is a "leaf"
> lock, beneath which nothing else (in libpcp) is nested. ...

The point I was making was that there are a bunch of newly added local mutexes as well as __pmLock_extcall ... the new ones are named foo_lock for local control within the foo.c source file ...

kenj@bozo:~/src/pcp/src/libpcp_fault/src$ grep '[a-z]_lock.*INIT' *.[cy]
auxconnect.c:static pthread_mutex_t	auxconnect_lock = PTHREAD_MUTEX_INITIALIZER;
config.c:static pthread_mutex_t	config_lock = PTHREAD_MUTEX_INITIALIZER;
fault.c:static pthread_mutex_t	fault_lock = PTHREAD_MUTEX_INITIALIZER;
pdubuf.c:static pthread_mutex_t	pdubuf_lock = PTHREAD_MUTEX_INITIALIZER;
pdu.c:static pthread_mutex_t	pdu_lock = PTHREAD_MUTEX_INITIALIZER;
util.c:static pthread_mutex_t	util_lock = PTHREAD_MUTEX_INITIALIZER;

and these ones are non-leaves in the lock graph, but are _only_ allowed to lock __pmLock_extcall once a foo_lock is held.

So I'm asserting that level N (__pmLock_extcall) and level N-1 (all the foo_lock mutexes) are deadlock free.

-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links:

You receive all messages sent to this group.

View/Reply Online (#14993): https://groups.io/g/pcp/message/14993
View All Messages In Topic (7): https://groups.io/g/pcp/topic/4185439
Mute This Topic: https://groups.io/mt/4185439?uid=174580
New Topic: https://groups.io/g/pcp/post
-=-=-
pcp mailing list
[email protected]
https://groups.io/g/pcp/messages
-=-=-
Change Your Subscription: https://groups.io/g/pcp/editsub?uid=174580
Group Home: https://groups.io/g/pcp
Contact Group Owner: [email protected]
Terms of Service: https://groups.io/static/tos
Unsubscribe: https://groups.io/g/pcp/leave/354243/563757577/xyzzy
-=-=-=-=-=-=-=-=-=-=-=-