svn commit: r368283 - head/sys/dev/cxgbe

[Navdeep Parhar]

Author: np
Date: Wed Dec  2 20:54:03 2020
New Revision: 368283
URL: https://svnweb.freebsd.org/changeset/base/368283

Log:
  cxgbe(4): Revert r367917.
  
  r367917 fixed the backpressure on the netmap rxq being stopped but that
  doesn't help if some other netmap rxq is starved (because it is stopping
  too although the driver doesn't know this yet) and blocks the pipeline.
  An alternate fix that works in all cases will be checked in instead.
  
  Sponsored by:	Chelsio Communications

Modified:
  head/sys/dev/cxgbe/adapter.h
  head/sys/dev/cxgbe/t4_netmap.c

Modified: head/sys/dev/cxgbe/adapter.h
==============================================================================
--- head/sys/dev/cxgbe/adapter.h	Wed Dec  2 19:58:50 2020	(r368282)
+++ head/sys/dev/cxgbe/adapter.h	Wed Dec  2 20:54:03 2020	(r368283)
@@ -749,9 +749,6 @@ struct sge_nm_rxq {
 	bus_dma_tag_t fl_desc_tag;
 	bus_dmamap_t fl_desc_map;
 	bus_addr_t fl_ba;
-
-	void *bb;		/* bit bucket for packets with nowhere to go. */
-	uma_zone_t bb_zone;
 };
 
 #define INVALID_NM_TXQ_CNTXT_ID ((u_int)(-1))

Modified: head/sys/dev/cxgbe/t4_netmap.c
==============================================================================
--- head/sys/dev/cxgbe/t4_netmap.c	Wed Dec  2 19:58:50 2020	(r368282)
+++ head/sys/dev/cxgbe/t4_netmap.c	Wed Dec  2 20:54:03 2020	(r368283)
@@ -42,8 +42,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/socket.h>
 #include <sys/sockio.h>
 #include <machine/bus.h>
-#include <vm/vm.h>
-#include <vm/pmap.h>
 #include <net/ethernet.h>
 #include <net/if.h>
 #include <net/if_media.h>
@@ -588,8 +586,6 @@ cxgbe_netmap_on(struct adapter *sc, struct vi_info *vi
 
 		alloc_nm_rxq_hwq(vi, nm_rxq, tnl_cong(vi->pi, nm_cong_drop));
 		nm_rxq->fl_hwidx = hwidx;
-		nm_rxq->bb_zone = rxb->zone;
-		nm_rxq->bb = uma_zalloc(nm_rxq->bb_zone, M_WAITOK);
 		slot = netmap_reset(na, NR_RX, i, 0);
 		MPASS(slot != NULL);	/* XXXNM: error check, not assert */
 
@@ -632,31 +628,6 @@ cxgbe_netmap_on(struct adapter *sc, struct vi_info *vi
 	return (cxgbe_netmap_rss(sc, vi, ifp, na));
 }
 
-static void
-flush_nm_rxq(struct adapter *sc, struct vi_info *vi, struct sge_nm_rxq *nm_rxq)
-{
-	int i, n;
-	u_int fl_pidx, fl_pidx_target, hw_cidx_desc;
-	const uint64_t ba = pmap_kextract((vm_offset_t)nm_rxq->bb);
-
-	hw_cidx_desc = nm_rxq->fl_cidx / 8;
-	if (hw_cidx_desc == 0)
-		fl_pidx_target = nm_rxq->fl_sidx2 - 8;
-	else
-		fl_pidx_target = (hw_cidx_desc - 1) * 8;
-	MPASS((fl_pidx_target & 7) == 0);
-
-	fl_pidx = nm_rxq->fl_pidx;
-	MPASS((fl_pidx & 7) == 0);
-	for (n = 0; fl_pidx != fl_pidx_target; n++) {
-		for (i = 0; i < 8; i++, fl_pidx++)
-			nm_rxq->fl_desc[fl_pidx] = htobe64(ba | nm_rxq->fl_hwidx);
-		if (__predict_false(fl_pidx == nm_rxq->fl_sidx2))
-			fl_pidx = 0;
-	}
-	t4_write_reg(sc, sc->sge_kdoorbell_reg, nm_rxq->fl_db_val | V_PIDX(n));
-}
-
 static int
 cxgbe_netmap_off(struct adapter *sc, struct vi_info *vi, struct ifnet *ifp,
     struct netmap_adapter *na)
@@ -681,23 +652,6 @@ cxgbe_netmap_off(struct adapter *sc, struct vi_info *v
 	if (rc != 0)
 		return (rc);	/* error message logged already. */
 
-	/*
-	 * First pass over the rx queues to make sure they're all caught up.
-	 *
-	 * The freelists could be out of buffers and we may need to arrange
-	 * things so that any packets still in flight (after TP's cong_drop
-	 * logic but not yet DMA'd) have somewhere to go and do not block the
-	 * pipeline.  Do this before trying to free any queue.
-	 */
-	for_each_nm_rxq(vi, i, nm_rxq) {
-		nm_state = atomic_load_int(&nm_rxq->nm_state);
-		kring = na->rx_rings[nm_rxq->nid];
-		if (nm_state == NM_OFF || !nm_kring_pending_off(kring))
-			continue;
-		MPASS(nm_rxq->iq_cntxt_id != INVALID_NM_RXQ_CNTXT_ID);
-		flush_nm_rxq(sc, vi, nm_rxq);
-	}
-
 	for_each_nm_txq(vi, i, nm_txq) {
 		struct sge_qstat *spg = (void *)&nm_txq->desc[nm_txq->sidx];
 
@@ -734,8 +688,6 @@ cxgbe_netmap_off(struct adapter *sc, struct vi_info *v
 			pause("nmst", 1);
 
 		free_nm_rxq_hwq(vi, nm_rxq);
-		uma_zfree(nm_rxq->bb_zone, nm_rxq->bb);
-		nm_rxq->bb = NULL;
 
 		/* XXX: netmap, not the driver, should do this. */
 		kring->rhead = kring->rcur = kring->nr_hwcur = 0;