On Tue, 4 Jun 2013 17:59:50 -0400 "J. Bruce Fields" <bfie...@fieldses.org> wrote:
> On Fri, May 31, 2013 at 11:07:31PM -0400, Jeff Layton wrote: > > Testing has shown that iterating over the blocked_list for deadlock > > detection turns out to be a bottleneck. In order to alleviate that, > > begin the process of turning it into a hashtable. We start by turning > > the fl_link into a hlist_node and the global lists into hlists. A later > > patch will do the conversion of the blocked_list to a hashtable. > > Even simpler would be if we could add a pointer to the (well, a) lock > that a lockowner is blocking on, and then we'd just have to follow a > pointer. I haven't thought that through, though, perhaps that's hard ot > make work.... > > --b. > I considered that as well and it makes sense for the simple local filesystem case where you just track ownership based on fl_owner_t. But...what about lockd? It considers ownership to be a tuple of the nlm_host and the pid sent in a lock request. I can't seem to wrap my brain around how to make such an approach work there. I'll confess though that I haven't tried *too* hard yet though since I had bigger problems to sort through at the time. Maybe we can consider that for a later set? > > > > Signed-off-by: Jeff Layton <jlay...@redhat.com> > > --- > > fs/locks.c | 32 ++++++++++++++++---------------- > > include/linux/fs.h | 2 +- > > 2 files changed, 17 insertions(+), 17 deletions(-) > > > > diff --git a/fs/locks.c b/fs/locks.c > > index fc35b9e..5ed056b 100644 > > --- a/fs/locks.c > > +++ b/fs/locks.c > > @@ -163,8 +163,8 @@ int lease_break_time = 45; > > #define for_each_lock(inode, lockp) \ > > for (lockp = &inode->i_flock; *lockp != NULL; lockp = > > &(*lockp)->fl_next) > > > > -static LIST_HEAD(file_lock_list); > > -static LIST_HEAD(blocked_list); > > +static HLIST_HEAD(file_lock_list); > > +static HLIST_HEAD(blocked_list); > > > > /* Protects the two list heads above */ > > static DEFINE_SPINLOCK(file_lock_lock); > > @@ -173,7 +173,7 @@ static struct kmem_cache *filelock_cache __read_mostly; > > > > static void locks_init_lock_heads(struct file_lock *fl) > > { > > - INIT_LIST_HEAD(&fl->fl_link); > > + INIT_HLIST_NODE(&fl->fl_link); > > INIT_LIST_HEAD(&fl->fl_block); > > init_waitqueue_head(&fl->fl_wait); > > } > > @@ -207,7 +207,7 @@ void locks_free_lock(struct file_lock *fl) > > { > > BUG_ON(waitqueue_active(&fl->fl_wait)); > > BUG_ON(!list_empty(&fl->fl_block)); > > - BUG_ON(!list_empty(&fl->fl_link)); > > + BUG_ON(!hlist_unhashed(&fl->fl_link)); > > > > locks_release_private(fl); > > kmem_cache_free(filelock_cache, fl); > > @@ -486,7 +486,7 @@ static inline void > > locks_insert_global_blocked(struct file_lock *waiter) > > { > > spin_lock(&file_lock_lock); > > - list_add(&waiter->fl_link, &blocked_list); > > + hlist_add_head(&waiter->fl_link, &blocked_list); > > spin_unlock(&file_lock_lock); > > } > > > > @@ -494,7 +494,7 @@ static inline void > > locks_delete_global_blocked(struct file_lock *waiter) > > { > > spin_lock(&file_lock_lock); > > - list_del_init(&waiter->fl_link); > > + hlist_del_init(&waiter->fl_link); > > spin_unlock(&file_lock_lock); > > } > > > > @@ -502,7 +502,7 @@ static inline void > > locks_insert_global_locks(struct file_lock *waiter) > > { > > spin_lock(&file_lock_lock); > > - list_add_tail(&waiter->fl_link, &file_lock_list); > > + hlist_add_head(&waiter->fl_link, &file_lock_list); > > spin_unlock(&file_lock_lock); > > } > > > > @@ -510,7 +510,7 @@ static inline void > > locks_delete_global_locks(struct file_lock *waiter) > > { > > spin_lock(&file_lock_lock); > > - list_del_init(&waiter->fl_link); > > + hlist_del_init(&waiter->fl_link); > > spin_unlock(&file_lock_lock); > > } > > > > @@ -705,7 +705,7 @@ static struct file_lock > > *what_owner_is_waiting_for(struct file_lock *block_fl) > > { > > struct file_lock *fl, *ret = NULL; > > > > - list_for_each_entry(fl, &blocked_list, fl_link) { > > + hlist_for_each_entry(fl, &blocked_list, fl_link) { > > if (posix_same_owner(fl, block_fl)) { > > ret = fl->fl_next; > > if (likely(ret)) > > @@ -867,7 +867,7 @@ static int __posix_lock_file(struct inode *inode, > > struct file_lock *request, str > > goto out; > > error = FILE_LOCK_DEFERRED; > > locks_insert_block(fl, request); > > - if (list_empty(&request->fl_link)) > > + if (hlist_unhashed(&request->fl_link)) > > locks_insert_global_blocked(request); > > goto out; > > } > > @@ -882,10 +882,10 @@ static int __posix_lock_file(struct inode *inode, > > struct file_lock *request, str > > * Now that we know the request is no longer blocked, we can take it > > * off the global list. Some callers send down partially initialized > > * requests, so we only do this if FL_SLEEP is set. Also, avoid taking > > - * the lock if the list is empty, as that indicates a request that > > + * the lock if the hlist is unhashed, as that indicates a request that > > * never blocked. > > */ > > - if ((request->fl_flags & FL_SLEEP) && !list_empty(&request->fl_link)) > > + if ((request->fl_flags & FL_SLEEP) && > > !hlist_unhashed(&request->fl_link)) > > locks_delete_global_blocked(request); > > > > /* > > @@ -2277,11 +2277,11 @@ static int locks_show(struct seq_file *f, void *v) > > { > > struct file_lock *fl, *bfl; > > > > - fl = list_entry(v, struct file_lock, fl_link); > > + fl = hlist_entry(v, struct file_lock, fl_link); > > > > lock_get_status(f, fl, *((loff_t *)f->private), ""); > > > > - list_for_each_entry(bfl, &blocked_list, fl_link) { > > + hlist_for_each_entry(bfl, &blocked_list, fl_link) { > > if (bfl->fl_next == fl) > > lock_get_status(f, bfl, *((loff_t *)f->private), " ->"); > > } > > @@ -2295,14 +2295,14 @@ static void *locks_start(struct seq_file *f, loff_t > > *pos) > > > > spin_lock(&file_lock_lock); > > *p = (*pos + 1); > > - return seq_list_start(&file_lock_list, *pos); > > + return seq_hlist_start(&file_lock_list, *pos); > > } > > > > static void *locks_next(struct seq_file *f, void *v, loff_t *pos) > > { > > loff_t *p = f->private; > > ++*p; > > - return seq_list_next(v, &file_lock_list, pos); > > + return seq_hlist_next(v, &file_lock_list, pos); > > } > > > > static void locks_stop(struct seq_file *f, void *v) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > > index ccb44ea..07a009e 100644 > > --- a/include/linux/fs.h > > +++ b/include/linux/fs.h > > @@ -934,7 +934,7 @@ int locks_in_grace(struct net *); > > */ > > struct file_lock { > > struct file_lock *fl_next; /* singly linked list for this inode */ > > - struct list_head fl_link; /* doubly linked list of all locks */ > > + struct hlist_node fl_link; /* node in global lists */ > > struct list_head fl_block; /* circular list of blocked processes */ > > fl_owner_t fl_owner; > > unsigned int fl_flags; > > -- > > 1.7.1 > > -- Jeff Layton <jlay...@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html