On Thu 12-03-15 08:20:23, Josef Bacik wrote: > Some filesystems don't use the VFS inode hash and fake the fact they > are hashed so that all the writeback code works correctly. However, > this means the evict() path still tries to remove the inode from the > hash, meaning that the inode_hash_lock() needs to be taken > unnecessarily. Hence under certain workloads the inode_hash_lock can > be contended even if the inode is never actually hashed. > > To avoid this add hlist_fake to test if the inode isn't actually > hashed to avoid taking the hash lock on inodes that have never been > hashed. Based on Dave Chinner's > > inode: add IOP_NOTHASHED to avoid inode hash lock in evict > > basd on Al's suggestions. Thanks, > > Signed-off-by: Josef Bacik <jbacik@xxxxxx> Looks good. You can add: Reviewed-by: Jan Kara <jack@xxxxxxx> Honza > --- > V1->V2: Argh sorry, forgot to reset the author, my bad. > > include/linux/fs.h | 2 +- > include/linux/list.h | 5 +++++ > 2 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index b4d71b5..31da757 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2528,7 +2528,7 @@ static inline void insert_inode_hash(struct inode *inode) > extern void __remove_inode_hash(struct inode *); > static inline void remove_inode_hash(struct inode *inode) > { > - if (!inode_unhashed(inode)) > + if (!inode_unhashed(inode) && !hlist_fake(&inode->i_hash)) > __remove_inode_hash(inode); > } > > diff --git a/include/linux/list.h b/include/linux/list.h > index feb773c..3e3e64a 100644 > --- a/include/linux/list.h > +++ b/include/linux/list.h > @@ -672,6 +672,11 @@ static inline void hlist_add_fake(struct hlist_node *n) > n->pprev = &n->next; > } > > +static inline bool hlist_fake(struct hlist_node *h) > +{ > + return h->pprev == &h->next; > +} > + > /* > * Move a list from one list head to another. Fixup the pprev > * reference of the first entry if it exists. > -- > 1.9.3 > -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html