Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751802Ab3FDWAV (ORCPT ); Tue, 4 Jun 2013 18:00:21 -0400 Received: from fieldses.org ([174.143.236.118]:57940 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751678Ab3FDWAR (ORCPT ); Tue, 4 Jun 2013 18:00:17 -0400 Date: Tue, 4 Jun 2013 17:59:50 -0400 From: "J. Bruce Fields" To: Jeff Layton Cc: viro@zeniv.linux.org.uk, matthew@wil.cx, 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: Re: [PATCH v1 08/11] locks: convert fl_link to a hlist_node Message-ID: <20130604215950.GE15594@fieldses.org> References: <1370056054-25449-1-git-send-email-jlayton@redhat.com> <1370056054-25449-9-git-send-email-jlayton@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1370056054-25449-9-git-send-email-jlayton@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6289 Lines: 173 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. > > Signed-off-by: Jeff Layton > --- > 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 > -- 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/