On Mon, Feb 12, 2018 at 01:16:28PM +0100, Michal Privoznik wrote: > On 02/12/2018 01:10 PM, Peter Krempa wrote: > > On Mon, Feb 12, 2018 at 11:52:49 +0100, Michal Privoznik wrote: > >> Sometimes we need the lock in virObjectLockable to be recursive. > >> Because of the nature of pthreads we don't need a special class > >> for that - the pthread_* APIs don't distinguish between normal > >> and recursive locks. > >> > >> Based-on-work-of: John Ferlan <jferlan@xxxxxxxxxx> > >> Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx> > >> --- > >> src/libvirt_private.syms | 1 + > >> src/util/virobject.c | 22 +++++++++++++++++++--- > >> src/util/virobject.h | 4 ++++ > >> 3 files changed, 24 insertions(+), 3 deletions(-) > >> > >> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms > >> index 3b14d7d15..fcf378105 100644 > >> --- a/src/libvirt_private.syms > >> +++ b/src/libvirt_private.syms > >> @@ -2417,6 +2417,7 @@ virObjectListFreeCount; > >> virObjectLock; > >> virObjectLockableNew; > >> virObjectNew; > >> +virObjectRecursiveLockableNew; > > > > I think this was NACK'd last time since we did not want to promote usage > > of recursive locks in the code. If we provide an object that provides > > recursive locking we de-facto promote this usage. > > > > As Pavel stated in his review. Ideally the NWfilter code will be > > converted to a less convoluted locking not requiring recursive locks > > prior to this so that we don't have to add recursive locking at all. > > > > I think that is far from happening. And I don't see any difference > between virObjectRecursiveLockableNew() and > virMutexInitRecursive() in terms of promoting something. Can you shed > more light where do you see the difference? IMHO the difference is what Peter already wrote, creating new object that automatically uses recursive locks makes it easier to use and somehow promotes it, because nowadays we are rewriting a lot of code to use objects. The other argument is that we should avoid recursive locks which includes not introducing new code that works with recursive locks. I know that NWFilter code is complex and removing recursive locks is not an easy task, but for the long run I think it's worth it, it will make the code cleaner and easier to follow. In conclusion, I still stand behind my NACK. Pavel > > Michal > > -- > libvir-list mailing list > libvir-list@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/libvir-list
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