From patchwork Fri Jun 21 12:58:18 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 2762351 Return-Path: X-Original-To: patchwork-ceph-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 052D6C0AB1 for ; Fri, 21 Jun 2013 13:00:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CBD5C2023B for ; Fri, 21 Jun 2013 13:00:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1898720235 for ; Fri, 21 Jun 2013 13:00:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422724Ab3FUM7J (ORCPT ); Fri, 21 Jun 2013 08:59:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53895 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161416Ab3FUM7G (ORCPT ); Fri, 21 Jun 2013 08:59:06 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r5LCwZdS022532 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 21 Jun 2013 08:58:35 -0400 Received: from sikun.lab.eng.rdu2.redhat.com (sikun.lab.eng.rdu2.redhat.com [10.8.0.43]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r5LCwMik014591; Fri, 21 Jun 2013 08:58:34 -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 v4 10/14] locks: turn the blocked_list into a hashtable Date: Fri, 21 Jun 2013 08:58:18 -0400 Message-Id: <1371819502-26363-11-git-send-email-jlayton@redhat.com> In-Reply-To: <1371819502-26363-1-git-send-email-jlayton@redhat.com> References: <1371819502-26363-1-git-send-email-jlayton@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 Sender: ceph-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org X-Spam-Status: No, score=-8.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 Acked-by: J. Bruce Fields --- fs/locks.c | 25 +++++++++++++++++-------- 1 files changed, 17 insertions(+), 8 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 941b714..71d847c 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -126,6 +126,7 @@ #include #include #include +#include #include @@ -160,13 +161,21 @@ int lease_break_time = 45; static HLIST_HEAD(file_lock_list); /* - * The blocked_list is used to find POSIX lock loops for deadlock detection. - * Protected by file_lock_lock. + * The blocked_hash is used to find POSIX lock loops for deadlock detection. + * It is protected by file_lock_lock. + * + * We hash locks by lockowner in order to optimize searching for the lock a + * particular lockowner is waiting on. + * + * FIXME: make this value scale via some heuristic? We generally will want more + * buckets when we have more lockowners holding locks, but that's a little + * difficult to determine without knowing what the workload will look like. */ -static HLIST_HEAD(blocked_list); +#define BLOCKED_HASH_BITS 7 +static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); /* - * This lock protects the blocked_list, and the file_lock_list. Generally, if + * This lock protects the blocked_hash and the file_lock_list. Generally, if * you're accessing one of those lists, you want to be holding this lock. * * In addition, it also protects the fl->fl_block list, and the fl->fl_next @@ -515,13 +524,13 @@ locks_delete_global_locks(struct file_lock *fl) 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); } /* Remove waiter from blocker's block list. @@ -748,7 +757,7 @@ 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; } @@ -884,7 +893,7 @@ 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) {