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Date:      Thu, 23 Feb 2012 08:22:44 +0000 (UTC)
From:      Pyun YongHyeon <yongari@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r232040 - head/sys/dev/sf
Message-ID:  <201202230822.q1N8Mik4091539@svn.freebsd.org>
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Author: yongari
Date: Thu Feb 23 08:22:44 2012
New Revision: 232040
URL: http://svn.freebsd.org/changeset/base/232040

Log:
  Add check for IFF_DRV_RUNNING flag after serving an interrupt and
  don't give RX path more priority than TX path.
  Also remove infinite loop in interrupt handler and limit number of
  iteration to 32. This change addresses system load fluctuations
  under high network load.

Modified:
  head/sys/dev/sf/if_sf.c

Modified: head/sys/dev/sf/if_sf.c
==============================================================================
--- head/sys/dev/sf/if_sf.c	Thu Feb 23 07:56:19 2012	(r232039)
+++ head/sys/dev/sf/if_sf.c	Thu Feb 23 08:22:44 2012	(r232040)
@@ -1549,7 +1549,9 @@ sf_rxeof(struct sf_softc *sc)
 	 */
 	eidx = 0;
 	prog = 0;
-	for (cons = sc->sf_cdata.sf_rxc_cons; ; SF_INC(cons, SF_RX_CLIST_CNT)) {
+	for (cons = sc->sf_cdata.sf_rxc_cons;
+	    (ifp->if_drv_flags & IFF_DRV_RUNNING) != 0;
+	    SF_INC(cons, SF_RX_CLIST_CNT)) {
 		cur_cmp = &sc->sf_rdata.sf_rx_cring[cons];
 		status = le32toh(cur_cmp->sf_rx_status1);
 		if (status == 0)
@@ -1852,6 +1854,7 @@ sf_intr(void *arg)
 	struct sf_softc		*sc;
 	struct ifnet		*ifp;
 	uint32_t		status;
+	int			cnt;
 
 	sc = (struct sf_softc *)arg;
 	SF_LOCK(sc);
@@ -1870,13 +1873,13 @@ sf_intr(void *arg)
 	if ((ifp->if_capenable & IFCAP_POLLING) != 0)
 		goto done_locked;
 #endif
-	if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
-		goto done_locked;
 
 	/* Disable interrupts. */
 	csr_write_4(sc, SF_IMR, 0x00000000);
 
-	for (; (status & SF_INTRS) != 0;) {
+	for (cnt = 32; (status & SF_INTRS) != 0;) {
+		if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
+			break;
 		if ((status & SF_ISR_RXDQ1_DMADONE) != 0)
 			sf_rxeof(sc);
 
@@ -1911,15 +1914,19 @@ sf_intr(void *arg)
 #endif
 			}
 		}
+		if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
+			sf_start_locked(ifp);
+		if (--cnt <= 0)
+			break;
 		/* Reading the ISR register clears all interrrupts. */
 		status = csr_read_4(sc, SF_ISR);
 	}
 
-	/* Re-enable interrupts. */
-	csr_write_4(sc, SF_IMR, SF_INTRS);
+	if ((ifp->if_drv_flags & IFF_DRV_RUNNING) != 0) {
+		/* Re-enable interrupts. */
+		csr_write_4(sc, SF_IMR, SF_INTRS);
+	}
 
-	if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
-		sf_start_locked(ifp);
 done_locked:
 	SF_UNLOCK(sc);
 }

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