On Fri 23-10-15 15:06:59, Jeff Layton wrote: > At the time that this code was originally written, call_srcu didn't > exist, so this thread was required to ensure that we waited for that > SRCU grace period to settle before finally freeing the object. > > It does exist now however and we can much more efficiently use call_srcu > to handle this. That also allows us to potentially use srcu_barrier > to ensure that they are all of the callbacks have run before proceeding. > In order to conserve space, we union the rcu_head with the g_list. > > This will be necessary for nfsd which will allocate marks from a > dedicated slabcache. We have to be able to ensure that all of the > objects are destroyed before destroying the cache. That's fairly > difficult to ensure with dedicated thread doing the destruction.
The patch looks good. Just one nit below: > diff --git a/include/linux/fsnotify_backend.h > b/include/linux/fsnotify_backend.h > index 533c4408529a..6b7e89f45aa4 100644 > --- a/include/linux/fsnotify_backend.h > +++ b/include/linux/fsnotify_backend.h > @@ -220,7 +220,10 @@ struct fsnotify_mark { > /* List of marks by group->i_fsnotify_marks. Also reused for queueing > * mark into destroy_list when it's waiting for the end of SRCU period > * before it can be freed. [group->mark_mutex] */ Please update this comment to not speak about destroy_list. After that feel free to add: Reviewed-by: Jan Kara <j...@suse.com> Honza > - struct list_head g_list; > + union { > + struct list_head g_list; > + struct rcu_head g_rcu; > + }; > /* Protects inode / mnt pointers, flags, masks */ > spinlock_t lock; > /* List of marks for inode / vfsmount [obj_lock] */ Honza -- Jan Kara <j...@suse.com> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/