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From: Navdeep Parhar <np@FreeBSD.org>
Date: Wed, 20 Apr 2011 23:20:00 +0000 (UTC)
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Subject: svn commit: r220905 - head/sys/dev/cxgbe
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Author: np
Date: Wed Apr 20 23:20:00 2011
New Revision: 220905
URL: http://svn.freebsd.org/changeset/base/220905
Log:
Ring the freelist doorbell from within refill_fl. While here, fix a bug
that could have allowed the hardware pidx to reach the cidx even though
the freelist isn't empty. (Haven't actually seen this but it was there
waiting to happen..)
MFC after: 1 week
Modified:
head/sys/dev/cxgbe/t4_sge.c
Modified: head/sys/dev/cxgbe/t4_sge.c
==============================================================================
--- head/sys/dev/cxgbe/t4_sge.c Wed Apr 20 23:17:17 2011 (r220904)
+++ head/sys/dev/cxgbe/t4_sge.c Wed Apr 20 23:20:00 2011 (r220905)
@@ -114,7 +114,7 @@ static void oneseg_dma_callback(void *,
static inline bool is_new_response(const struct sge_iq *, struct rsp_ctrl **);
static inline void iq_next(struct sge_iq *);
static inline void ring_fl_db(struct adapter *, struct sge_fl *);
-static void refill_fl(struct sge_fl *, int);
+static void refill_fl(struct adapter *, struct sge_fl *, int, int);
static int alloc_fl_sdesc(struct sge_fl *);
static void free_fl_sdesc(struct sge_fl *);
static int alloc_tx_maps(struct sge_txq *);
@@ -763,9 +763,7 @@ t4_eth_rx(void *arg)
FL_LOCK(fl);
fl->needed += i;
if (fl->needed >= 32)
- refill_fl(fl, 64);
- if (fl->pending >= 32)
- ring_fl_db(sc, fl);
+ refill_fl(sc, fl, 64, 32);
FL_UNLOCK(fl);
nextdesc: ndescs++;
@@ -793,9 +791,7 @@ nextdesc: ndescs++;
FL_LOCK(fl);
if (fl->needed >= 32)
- refill_fl(fl, 128);
- if (fl->pending >= 8)
- ring_fl_db(sc, fl);
+ refill_fl(sc, fl, 128, 8);
FL_UNLOCK(fl);
}
@@ -1179,7 +1175,7 @@ alloc_iq_fl(struct port_info *pi, struct
rc);
return (rc);
}
- fl->needed = fl->cap - 1; /* one less to avoid cidx = pidx */
+ fl->needed = fl->cap;
c.iqns_to_fl0congen =
htobe32(V_FW_IQ_CMD_FL0HOSTFCMODE(X_HOSTFCMODE_NONE));
@@ -1222,9 +1218,7 @@ alloc_iq_fl(struct port_info *pi, struct
sc->sge.eqmap[cntxt_id] = (void *)fl;
FL_LOCK(fl);
- refill_fl(fl, -1);
- if (fl->pending >= 8)
- ring_fl_db(sc, fl);
+ refill_fl(sc, fl, -1, 8);
FL_UNLOCK(fl);
}
@@ -1692,24 +1686,31 @@ iq_next(struct sge_iq *iq)
}
}
+#define FL_HW_IDX(x) ((x) >> 3)
static inline void
ring_fl_db(struct adapter *sc, struct sge_fl *fl)
{
int ndesc = fl->pending / 8;
- /* Caller responsible for ensuring there's something useful to do */
- KASSERT(ndesc > 0, ("%s called with no useful work to do.", __func__));
+ if (FL_HW_IDX(fl->pidx) == FL_HW_IDX(fl->cidx))
+ ndesc--; /* hold back one credit */
+
+ if (ndesc <= 0)
+ return; /* nothing to do */
wmb();
t4_write_reg(sc, MYPF_REG(A_SGE_PF_KDOORBELL), F_DBPRIO |
V_QID(fl->cntxt_id) | V_PIDX(ndesc));
-
- fl->pending &= 7;
+ fl->pending -= ndesc * 8;
}
+/*
+ * Fill up the freelist by upto nbufs and ring its doorbell if the number of
+ * buffers ready to be handed to the hardware >= dbthresh.
+ */
static void
-refill_fl(struct sge_fl *fl, int nbufs)
+refill_fl(struct adapter *sc, struct sge_fl *fl, int nbufs, int dbthresh)
{
__be64 *d = &fl->desc[fl->pidx];
struct fl_sdesc *sd = &fl->sdesc[fl->pidx];
@@ -1800,6 +1801,9 @@ recycled:
d = fl->desc;
}
}
+
+ if (fl->pending >= dbthresh)
+ ring_fl_db(sc, fl);
}
static int