Date: Wed, 23 May 2012 12:51:49 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r235829 - head/sys/vm Message-ID: <201205231251.q4NCpnat073340@svn.freebsd.org>
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Author: avg Date: Wed May 23 12:51:49 2012 New Revision: 235829 URL: http://svn.freebsd.org/changeset/base/235829 Log: vm_pager_object_lookup: small performance optimization do not needlessly lock an object if its handle doesn't match Reviewed by: kib, alc MFC after: 1 week Modified: head/sys/vm/vm_pager.c Modified: head/sys/vm/vm_pager.c ============================================================================== --- head/sys/vm/vm_pager.c Wed May 23 11:26:28 2012 (r235828) +++ head/sys/vm/vm_pager.c Wed May 23 12:51:49 2012 (r235829) @@ -271,14 +271,15 @@ vm_pager_object_lookup(struct pagerlst * vm_object_t object; TAILQ_FOREACH(object, pg_list, pager_object_list) { - VM_OBJECT_LOCK(object); - if (object->handle == handle && - (object->flags & OBJ_DEAD) == 0) { - vm_object_reference_locked(object); + if (object->handle == handle) { + VM_OBJECT_LOCK(object); + if ((object->flags & OBJ_DEAD) == 0) { + vm_object_reference_locked(object); + VM_OBJECT_UNLOCK(object); + break; + } VM_OBJECT_UNLOCK(object); - break; } - VM_OBJECT_UNLOCK(object); } return (object); }
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