From owner-svn-src-stable-11@freebsd.org Thu Mar 23 07:57:39 2017 Return-Path: Delivered-To: svn-src-stable-11@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2996FD19FC3; Thu, 23 Mar 2017 07:57:39 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id ECD261AC; Thu, 23 Mar 2017 07:57:38 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id v2N7vcgm085923; Thu, 23 Mar 2017 07:57:38 GMT (envelope-from avg@FreeBSD.org) Received: (from avg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id v2N7vci8085922; Thu, 23 Mar 2017 07:57:38 GMT (envelope-from avg@FreeBSD.org) Message-Id: <201703230757.v2N7vci8085922@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: avg set sender to avg@FreeBSD.org using -f From: Andriy Gapon Date: Thu, 23 Mar 2017 07:57:38 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r315832 - stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs X-SVN-Group: stable-11 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable-11@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for only the 11-stable src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Mar 2017 07:57:39 -0000 Author: avg Date: Thu Mar 23 07:57:37 2017 New Revision: 315832 URL: https://svnweb.freebsd.org/changeset/base/315832 Log: MFC r314912: MFV r314910: 7843 get_clones_stat() is suboptimal for lots of clones Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c ============================================================================== --- stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c Thu Mar 23 07:56:13 2017 (r315831) +++ stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c Thu Mar 23 07:57:37 2017 (r315832) @@ -1766,11 +1766,22 @@ get_clones_stat(dsl_dataset_t *ds, nvlis zap_cursor_t zc; zap_attribute_t za; nvlist_t *propval = fnvlist_alloc(); - nvlist_t *val = fnvlist_alloc(); + nvlist_t *val; ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool)); /* + * We use nvlist_alloc() instead of fnvlist_alloc() because the + * latter would allocate the list with NV_UNIQUE_NAME flag. + * As a result, every time a clone name is appended to the list + * it would be (linearly) searched for for a duplicate name. + * We already know that all clone names must be unique and we + * want avoid the quadratic complexity of double-checking that + * because we can have a large number of clones. + */ + VERIFY0(nvlist_alloc(&val, 0, KM_SLEEP)); + + /* * There may be missing entries in ds_next_clones_obj * due to a bug in a previous version of the code. * Only trust it if it has the right number of entries.