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Date:      Fri, 6 Feb 2009 16:05:00 +0000 (UTC)
From:      John Baldwin <jhb@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: r188239 - in stable/7/sys: . contrib/pf dev/ath/ath_hal dev/cxgb kern
Message-ID:  <200902061605.n16G50pb065704@svn.freebsd.org>
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Author: jhb
Date: Fri Feb  6 16:05:00 2009
New Revision: 188239
URL: http://svn.freebsd.org/changeset/base/188239

Log:
  MFC: Push down Giant in the vlnru kproc main loop so that it is only acquired
  around calls to vlrureclaim() on non-MPSAFE filesystems.

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/kern/vfs_subr.c

Modified: stable/7/sys/kern/vfs_subr.c
==============================================================================
--- stable/7/sys/kern/vfs_subr.c	Fri Feb  6 15:28:08 2009	(r188238)
+++ stable/7/sys/kern/vfs_subr.c	Fri Feb  6 16:05:00 2009	(r188239)
@@ -717,15 +717,13 @@ static void
 vnlru_proc(void)
 {
 	struct mount *mp, *nmp;
-	int done;
+	int done, vfslocked;
 	struct proc *p = vnlruproc;
 	struct thread *td = curthread;
 
 	EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
 	    SHUTDOWN_PRI_FIRST);
 
-	mtx_lock(&Giant);
-
 	for (;;) {
 		kthread_suspend_check(p);
 		mtx_lock(&vnode_free_list_mtx);
@@ -742,19 +740,13 @@ vnlru_proc(void)
 		done = 0;
 		mtx_lock(&mountlist_mtx);
 		for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
-			int vfsunlocked;
 			if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
 				nmp = TAILQ_NEXT(mp, mnt_list);
 				continue;
 			}
-			if (!VFS_NEEDSGIANT(mp)) {
-				mtx_unlock(&Giant);
-				vfsunlocked = 1;
-			} else
-				vfsunlocked = 0;
+			vfslocked = VFS_LOCK_GIANT(mp);
 			done += vlrureclaim(mp);
-			if (vfsunlocked)
-				mtx_lock(&Giant);
+			VFS_UNLOCK_GIANT(vfslocked);
 			mtx_lock(&mountlist_mtx);
 			nmp = TAILQ_NEXT(mp, mnt_list);
 			vfs_unbusy(mp, td);

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