Re: [libvirt] [PATCH v2 0/6] nwfilter adjustments for common object

ping - perhaps at least the first 3... I'm now beginning to think/wonder if using the rwlock_rdlock would be the solution at least for nwfilter objs. It seems from a quick scan of the man page that they are designed to be recursive as long as the consumer guarantees that there is an Unlock for every LockRead. A lot better than rolling my own recursive lock algorithm that I tried in patch 4. Would require some other adjustments (and concessions) along the way, but seemingly possible. Tks - John On 07/18/2017 04:57 PM, John Ferlan wrote: > v1: https://www.redhat.com/archives/libvir-list/2017-June/msg00079.html > > Changes since v1 (if I can recall all of them!): > > Patches 1, 4, 8-13 were pushed > Patches 2, 3, 5-7 are dropped > > This this is a rework of patches 14-17 > > Patch 1 (former patch14): > * Requested adjustments made to ACK'd patch, but since this and the > remaining ones were related I didn't yet push it. > > Patch 2 (new): > * From review though... As it turns out, virNWFilterDefEqual doesn't > require the @cmpUUIDs patch. > > Patch 3 (fromer patch 15): > * Fixed the line as requested. Patch was ACK'd by like Patch 1 I held > onto it since it was related. > > Patch 4 (former patch 16): > * Let's call it a complete rewrite. Rather than rely solely on the > refcnt of the object, I've added/implemented a 'trylock' mechanism > which essentially will allow the subsequent patch to use the > virObjectLockable (e.g. a non recursive lock). Of course as I got > further into the code - I think I've come to the conclusion that > there isn't a way for a @def to disappear between threads with a > refcnt only mechanism because there's a few other serialized locks > which would need to be hurdled before hand. Still as I found out > while running the Avocado test 'nwfilter_update_vm_running.update_arp_rule' > the recursion would occur because the AssignDef code would call the > Instantiation with the lock from the def being updated and that's > where all the awful magic needs to occur. Additionally, I found that > one wouldn't want to attempt to lock the nwfilters list inside the > virNWFilterObjListFindInstantiateFilter because AssignDef already > had that lock. I debated needing a recursive lock there until I > came to the conclusion that the list couldn't change because the > DefineXML is protected by a driver level lock (as is the Undefine > and Reload paths). > > Patch 5 (former patch 17): > * No changes, it was ACK'd, but without 1-4 is useless > > Patch 6 (NEW): > * Remove the need for the driver level lock for a few API's since > we have self locking nwfilters list. Also left comments in the > 3 places where that lock remained to hopefully cause someone great > anxiety if they decided to attempt to remove the lock without > first consulting a specialist. > > NB: Ran all of the changes through the 'nwfilter' tests found in > the Avocado test suite. > > John Ferlan (6): > nwfilter: Add @refs logic to __virNWFilterObj > nwfilter: Remove unnecessary UUID comparison bypass > nwfilter: Convert _virNWFilterObjList to be a virObjectLockable > nwfilter: Remove recursive locking for nwfilter instantiation > nwfilter: Convert virNWFilterObj to use virObjectLockable > nwfilter: Remove need for nwfilterDriverLock in some API's > > src/conf/virnwfilterobj.c | 635 ++++++++++++++++++++++++--------- > src/conf/virnwfilterobj.h | 12 +- > src/libvirt_private.syms | 6 +- > src/nwfilter/nwfilter_driver.c | 66 ++-- > src/nwfilter/nwfilter_gentech_driver.c | 66 +++- > src/util/virobject.c | 24 ++ > src/util/virobject.h | 4 + > src/util/virthread.c | 5 + > src/util/virthread.h | 1 + > 9 files changed, 586 insertions(+), 233 deletions(-) > -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list