| Message ID | 1370948948-31784-11-git-send-email-jlayton@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jun 11, 2013 at 07:09:04AM -0400, Jeff Layton wrote: > Break up the blocked_list into a hashtable, using the fl_owner as a key. > This speeds up searching the hash chains, which is especially significant > for deadlock detection. > > Note that the initial implementation assumes that hashing on fl_owner is > sufficient. In most cases it should be, with the notable exception being > server-side lockd, which compares ownership using a tuple of the > nlm_host and the pid sent in the lock request. So, this may degrade to a > single hash bucket when you only have a single NFS client. That will be > addressed in a later patch. > > The careful observer may note that this patch leaves the file_lock_list > alone. There's much less of a case for turning the file_lock_list into a > hashtable. The only user of that list is the code that generates > /proc/locks, and it always walks the entire list. Makes sense to me, ACK to this and the previous patch.--b. > > Signed-off-by: Jeff Layton <jlayton@redhat.com> > --- > fs/locks.c | 25 ++++++++++++++++++------- > 1 files changed, 18 insertions(+), 7 deletions(-) > > diff --git a/fs/locks.c b/fs/locks.c > index 28959bc..76fb7af 100644 > --- a/fs/locks.c > +++ b/fs/locks.c > @@ -126,6 +126,7 @@ > #include <linux/time.h> > #include <linux/rcupdate.h> > #include <linux/pid_namespace.h> > +#include <linux/hashtable.h> > > #include <asm/uaccess.h> > > @@ -153,10 +154,19 @@ int lease_break_time = 45; > #define for_each_lock(inode, lockp) \ > for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next) > > +/* > + * By breaking up the blocked locks list into a hashtable, we speed up the > + * deadlock detection. > + * > + * FIXME: make this value scale via some heuristic? > + */ > +#define BLOCKED_HASH_BITS 7 > + > +static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); > + > static HLIST_HEAD(file_lock_list); > -static HLIST_HEAD(blocked_list); > > -/* Protects the two list heads above */ > +/* Protects the file_lock_list and the blocked_hash */ > static DEFINE_SPINLOCK(file_lock_lock); > > static struct kmem_cache *filelock_cache __read_mostly; > @@ -475,13 +485,13 @@ static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) > static inline void > locks_insert_global_blocked(struct file_lock *waiter) > { > - hlist_add_head(&waiter->fl_link, &blocked_list); > + hash_add(blocked_hash, &waiter->fl_link, (unsigned long)waiter->fl_owner); > } > > static inline void > __locks_delete_global_blocked(struct file_lock *waiter) > { > - hlist_del_init(&waiter->fl_link); > + hash_del(&waiter->fl_link); > } > > static inline void > @@ -729,7 +739,7 @@ static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) > { > struct file_lock *fl; > > - hlist_for_each_entry(fl, &blocked_list, fl_link) { > + hash_for_each_possible(blocked_hash, fl, fl_link, (unsigned long)block_fl->fl_owner) { > if (posix_same_owner(fl, block_fl)) > return fl->fl_next; > } > @@ -865,7 +875,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str > /* > * New lock request. Walk all POSIX locks and look for conflicts. If > * there are any, either return error or put the request on the > - * blocker's list of waiters and the global blocked_list. > + * blocker's list of waiters and the global blocked_hash. > */ > if (request->fl_type != F_UNLCK) { > for_each_lock(inode, before) { > @@ -2284,13 +2294,14 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, > > static int locks_show(struct seq_file *f, void *v) > { > + int bkt; > struct file_lock *fl, *bfl; > > fl = hlist_entry(v, struct file_lock, fl_link); > > lock_get_status(f, fl, *((loff_t *)f->private), ""); > > - hlist_for_each_entry(bfl, &blocked_list, fl_link) { > + hash_for_each(blocked_hash, bkt, bfl, fl_link) { > if (bfl->fl_next == fl) > lock_get_status(f, bfl, *((loff_t *)f->private), " ->"); > } > -- > 1.7.1 > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/locks.c b/fs/locks.c index 28959bc..76fb7af 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -126,6 +126,7 @@ #include <linux/time.h> #include <linux/rcupdate.h> #include <linux/pid_namespace.h> +#include <linux/hashtable.h> #include <asm/uaccess.h> @@ -153,10 +154,19 @@ int lease_break_time = 45; #define for_each_lock(inode, lockp) \ for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next) +/* + * By breaking up the blocked locks list into a hashtable, we speed up the + * deadlock detection. + * + * FIXME: make this value scale via some heuristic? + */ +#define BLOCKED_HASH_BITS 7 + +static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); + static HLIST_HEAD(file_lock_list); -static HLIST_HEAD(blocked_list); -/* Protects the two list heads above */ +/* Protects the file_lock_list and the blocked_hash */ static DEFINE_SPINLOCK(file_lock_lock); static struct kmem_cache *filelock_cache __read_mostly; @@ -475,13 +485,13 @@ static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) static inline void locks_insert_global_blocked(struct file_lock *waiter) { - hlist_add_head(&waiter->fl_link, &blocked_list); + hash_add(blocked_hash, &waiter->fl_link, (unsigned long)waiter->fl_owner); } static inline void __locks_delete_global_blocked(struct file_lock *waiter) { - hlist_del_init(&waiter->fl_link); + hash_del(&waiter->fl_link); } static inline void @@ -729,7 +739,7 @@ static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) { struct file_lock *fl; - hlist_for_each_entry(fl, &blocked_list, fl_link) { + hash_for_each_possible(blocked_hash, fl, fl_link, (unsigned long)block_fl->fl_owner) { if (posix_same_owner(fl, block_fl)) return fl->fl_next; } @@ -865,7 +875,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str /* * New lock request. Walk all POSIX locks and look for conflicts. If * there are any, either return error or put the request on the - * blocker's list of waiters and the global blocked_list. + * blocker's list of waiters and the global blocked_hash. */ if (request->fl_type != F_UNLCK) { for_each_lock(inode, before) { @@ -2284,13 +2294,14 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, static int locks_show(struct seq_file *f, void *v) { + int bkt; struct file_lock *fl, *bfl; fl = hlist_entry(v, struct file_lock, fl_link); lock_get_status(f, fl, *((loff_t *)f->private), ""); - hlist_for_each_entry(bfl, &blocked_list, fl_link) { + hash_for_each(blocked_hash, bkt, bfl, fl_link) { if (bfl->fl_next == fl) lock_get_status(f, bfl, *((loff_t *)f->private), " ->"); }
Break up the blocked_list into a hashtable, using the fl_owner as a key. This speeds up searching the hash chains, which is especially significant for deadlock detection. Note that the initial implementation assumes that hashing on fl_owner is sufficient. In most cases it should be, with the notable exception being server-side lockd, which compares ownership using a tuple of the nlm_host and the pid sent in the lock request. So, this may degrade to a single hash bucket when you only have a single NFS client. That will be addressed in a later patch. The careful observer may note that this patch leaves the file_lock_list alone. There's much less of a case for turning the file_lock_list into a hashtable. The only user of that list is the code that generates /proc/locks, and it always walks the entire list. Signed-off-by: Jeff Layton <jlayton@redhat.com> --- fs/locks.c | 25 ++++++++++++++++++------- 1 files changed, 18 insertions(+), 7 deletions(-)