Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932482Ab3FADKZ (ORCPT ); Fri, 31 May 2013 23:10:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:4912 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757526Ab3FADIN (ORCPT ); Fri, 31 May 2013 23:08:13 -0400 From: Jeff Layton To: viro@zeniv.linux.org.uk, matthew@wil.cx, bfields@fieldses.org Cc: dhowells@redhat.com, sage@inktank.com, smfrench@gmail.com, swhiteho@redhat.com, Trond.Myklebust@netapp.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-afs@lists.infradead.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, cluster-devel@redhat.com, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, piastryyy@gmail.com Subject: [PATCH v1 09/11] locks: turn the blocked_list into a hashtable Date: Fri, 31 May 2013 23:07:32 -0400 Message-Id: <1370056054-25449-10-git-send-email-jlayton@redhat.com> In-Reply-To: <1370056054-25449-1-git-send-email-jlayton@redhat.com> References: <1370056054-25449-1-git-send-email-jlayton@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3579 Lines: 107 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 --- fs/locks.c | 24 ++++++++++++++++++------ 1 files changed, 18 insertions(+), 6 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 5ed056b..0d030ce 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -126,6 +126,7 @@ #include #include #include +#include #include @@ -163,10 +164,19 @@ 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; @@ -486,7 +496,8 @@ static inline void locks_insert_global_blocked(struct file_lock *waiter) { spin_lock(&file_lock_lock); - hlist_add_head(&waiter->fl_link, &blocked_list); + hash_add(blocked_hash, &waiter->fl_link, + (unsigned long)waiter->fl_owner); spin_unlock(&file_lock_lock); } @@ -494,7 +505,7 @@ static inline void locks_delete_global_blocked(struct file_lock *waiter) { spin_lock(&file_lock_lock); - hlist_del_init(&waiter->fl_link); + hash_del(&waiter->fl_link); spin_unlock(&file_lock_lock); } @@ -705,7 +716,7 @@ static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) { struct file_lock *fl, *ret = NULL; - 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)) { ret = fl->fl_next; if (likely(ret)) @@ -2275,13 +2286,14 @@ 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 linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/