Date: Wed, 25 Feb 2009 11:44:03 +0000 (UTC) From: Robert Watson <rwatson@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org Subject: svn commit: r189031 - in stable/7/sys: . contrib/pf dev/ath/ath_hal dev/cxgb security/audit Message-ID: <200902251144.n1PBi3Jp095313@svn.freebsd.org>
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Author: rwatson Date: Wed Feb 25 11:44:03 2009 New Revision: 189031 URL: http://svn.freebsd.org/changeset/base/189031 Log: Merge r186825 from head to stable/7: Do a lockless read of the audit pipe list before grabbing the audit pipe lock in order to avoid the lock acquire hit if the pipe list is very likely empty. Obtained from: TrustedBSD Project Sponsored by: Apple, Inc. Modified: stable/7/sys/ (props changed) stable/7/sys/contrib/pf/ (props changed) stable/7/sys/dev/ath/ath_hal/ (props changed) stable/7/sys/dev/cxgb/ (props changed) stable/7/sys/security/audit/audit_pipe.c Modified: stable/7/sys/security/audit/audit_pipe.c ============================================================================== --- stable/7/sys/security/audit/audit_pipe.c Wed Feb 25 11:37:19 2009 (r189030) +++ stable/7/sys/security/audit/audit_pipe.c Wed Feb 25 11:44:03 2009 (r189031) @@ -407,6 +407,10 @@ audit_pipe_preselect(au_id_t auid, au_ev { struct audit_pipe *ap; + /* Lockless read to avoid acquiring the global lock if not needed. */ + if (TAILQ_EMPTY(&audit_pipe_list)) + return (0); + AUDIT_PIPE_LIST_RLOCK(); TAILQ_FOREACH(ap, &audit_pipe_list, ap_list) { AUDIT_PIPE_LOCK(ap);
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