Author: sbruno
Date: Tue Jan 24 14:48:32 2017
New Revision: 312696
URL: https://svnweb.freebsd.org/changeset/base/312696
Log:
iflib:
Add internal tracking of smp startup status to reliably figure out
what methods are to be used to get gtaskqueue up and running.
e1000:
Calculating this pointer gives undefined behaviour when (last == -1)
(it is before the buffer). The pointer is always followed. Panics
occurred when it points to an unmapped page. Otherwise, the pointed-to
garbage tends to not have the E1000_TXD_STAT_DD bit set in it, so in the
broken case the loop was usually null and the function just returned, and
this was acidentally correct.
Submitted by: bde
Reviewed by: Matt Macy <mm...@nextbsd.org>
Modified:
head/sys/dev/e1000/em_txrx.c
head/sys/kern/subr_gtaskqueue.c
head/sys/net/iflib.c
head/sys/sys/gtaskqueue.h
Modified: head/sys/dev/e1000/em_txrx.c
==============================================================================
--- head/sys/dev/e1000/em_txrx.c Tue Jan 24 12:15:10 2017
(r312695)
+++ head/sys/dev/e1000/em_txrx.c Tue Jan 24 14:48:32 2017
(r312696)
@@ -408,10 +408,13 @@ em_isc_txd_credits_update(void *arg, uin
cidx = cidx_init;
buf = &txr->tx_buffers[cidx];
tx_desc = &txr->tx_base[cidx];
- last = buf->eop;
+ last = buf->eop;
+ if (last == -1)
+ return (processed);
eop_desc = &txr->tx_base[last];
- DPRINTF(iflib_get_dev(adapter->ctx), "credits_update: cidx_init=%d
clear=%d last=%d\n",
+ DPRINTF(iflib_get_dev(adapter->ctx),
+ "credits_update: cidx_init=%d clear=%d last=%d\n",
cidx_init, clear, last);
/*
* What this does is get the index of the
@@ -420,7 +423,7 @@ em_isc_txd_credits_update(void *arg, uin
* simple comparison on the inner while loop.
*/
if (++last == scctx->isc_ntxd[0])
- last = 0;
+ last = 0;
done = last;
@@ -436,7 +439,7 @@ em_isc_txd_credits_update(void *arg, uin
tx_desc++;
buf++;
processed++;
-
+
/* wrap the ring ? */
if (++cidx == scctx->isc_ntxd[0]) {
cidx = 0;
Modified: head/sys/kern/subr_gtaskqueue.c
==============================================================================
--- head/sys/kern/subr_gtaskqueue.c Tue Jan 24 12:15:10 2017
(r312695)
+++ head/sys/kern/subr_gtaskqueue.c Tue Jan 24 14:48:32 2017
(r312696)
@@ -630,6 +630,29 @@ taskqgroup_find(struct taskqgroup *qgrou
return (idx);
}
+/*
+ * smp_started is unusable since it is not set for UP kernels or even for
+ * SMP kernels when there is 1 CPU. This is usually handled by adding a
+ * (mp_ncpus == 1) test, but that would be broken here since we need to
+ * to synchronize with the SI_SUB_SMP ordering. Even in the pure SMP case
+ * smp_started only gives a fuzzy ordering relative to SI_SUB_SMP.
+ *
+ * So maintain our own flag. It must be set after all CPUs are started
+ * and before SI_SUB_SMP:SI_ORDER_ANY so that the SYSINIT for delayed
+ * adjustment is properly delayed. SI_ORDER_FOURTH is clearly before
+ * SI_ORDER_ANY and unclearly after the CPUs are started. It would be
+ * simpler for adjustment to pass a flag indicating if it is delayed.
+ */
+static int tqg_smp_started;
+
+static void
+tqg_record_smp_started(void *arg)
+{
+ tqg_smp_started = 1;
+}
+
+SYSINIT(tqg_record_smp_started, SI_SUB_SMP, SI_ORDER_FOURTH,
+ tqg_record_smp_started, NULL);
void
taskqgroup_attach(struct taskqgroup *qgroup, struct grouptask *gtask,
@@ -647,7 +670,7 @@ taskqgroup_attach(struct taskqgroup *qgr
qgroup->tqg_queue[qid].tgc_cnt++;
LIST_INSERT_HEAD(&qgroup->tqg_queue[qid].tgc_tasks, gtask, gt_list);
gtask->gt_taskqueue = qgroup->tqg_queue[qid].tgc_taskq;
- if (irq != -1 && (smp_started || mp_ncpus == 1)) {
+ if (irq != -1 && tqg_smp_started ) {
gtask->gt_cpu = qgroup->tqg_queue[qid].tgc_cpu;
CPU_ZERO(&mask);
CPU_SET(qgroup->tqg_queue[qid].tgc_cpu, &mask);
@@ -697,7 +720,7 @@ taskqgroup_attach_cpu(struct taskqgroup
gtask->gt_irq = irq;
gtask->gt_cpu = cpu;
mtx_lock(&qgroup->tqg_lock);
- if (smp_started || mp_ncpus == 1) {
+ if (tqg_smp_started)
for (i = 0; i < qgroup->tqg_cnt; i++)
if (qgroup->tqg_queue[i].tgc_cpu == cpu) {
qid = i;
@@ -731,7 +754,7 @@ taskqgroup_attach_cpu_deferred(struct ta
qid = -1;
irq = gtask->gt_irq;
cpu = gtask->gt_cpu;
- MPASS(smp_started || mp_ncpus == 1);
+ MPASS(tqg_smp_started);
mtx_lock(&qgroup->tqg_lock);
for (i = 0; i < qgroup->tqg_cnt; i++)
if (qgroup->tqg_queue[i].tgc_cpu == cpu) {
@@ -824,9 +847,10 @@ _taskqgroup_adjust(struct taskqgroup *qg
mtx_assert(&qgroup->tqg_lock, MA_OWNED);
- if (cnt < 1 || cnt * stride > mp_ncpus || (!smp_started && (mp_ncpus !=
1))) {
- printf("taskqgroup_adjust failed cnt: %d stride: %d mp_ncpus:
%d smp_started: %d\n",
- cnt, stride, mp_ncpus, smp_started);
+ if (cnt < 1 || cnt * stride > mp_ncpus || !tqg_smp_started) {
+ printf("%s: failed cnt: %d stride: %d "
+ "mp_ncpus: %d smp_started: %d\n",
+ __func__, cnt, stride, mp_ncpus, smp_started);
return (EINVAL);
}
if (qgroup->tqg_adjusting) {
Modified: head/sys/net/iflib.c
==============================================================================
--- head/sys/net/iflib.c Tue Jan 24 12:15:10 2017 (r312695)
+++ head/sys/net/iflib.c Tue Jan 24 14:48:32 2017 (r312696)
@@ -1193,13 +1193,36 @@ iflib_dma_free_multi(iflib_dma_info_t *d
iflib_dma_free(*dmaiter);
}
+#ifdef EARLY_AP_STARTUP
+static const int iflib_started = 1;
+#else
+/*
+ * We used to abuse the smp_started flag to decide if the queues have been
+ * fully initialized (by late taskqgroup_adjust() calls in a SYSINIT()).
+ * That gave bad races, since the SYSINIT() runs strictly after smp_started
+ * is set. Run a SYSINIT() strictly after that to just set a usable
+ * completion flag.
+ */
+
+static int iflib_started;
+
+static void
+iflib_record_started(void *arg)
+{
+ iflib_started = 1;
+}
+
+SYSINIT(iflib_record_started, SI_SUB_SMP + 1, SI_ORDER_FIRST,
+ iflib_record_started, NULL);
+#endif
+
static int
iflib_fast_intr(void *arg)
{
iflib_filter_info_t info = arg;
struct grouptask *gtask = info->ifi_task;
- if (!smp_started && mp_ncpus > 1)
+ if (!iflib_started)
return (FILTER_HANDLED);
DBG_COUNTER_INC(fast_intrs);
@@ -3728,7 +3751,16 @@ iflib_device_register(device_t dev, void
device_printf(dev, "qset structure setup failed %d\n", err);
goto fail_queues;
}
-
+ /*
+ * Group taskqueues aren't properly set up until SMP is started,
+ * so we disable interrupts until we can handle them post
+ * SI_SUB_SMP.
+ *
+ * XXX: disabling interrupts doesn't actually work, at least for
+ * the non-MSI case. When they occur before SI_SUB_SMP completes,
+ * we do null handling and depend on this not causing too large an
+ * interrupt storm.
+ */
IFDI_INTR_DISABLE(ctx);
if (msix > 1 && (err = IFDI_MSIX_INTR_ASSIGN(ctx, msix)) != 0) {
device_printf(dev, "IFDI_MSIX_INTR_ASSIGN failed %d\n", err);
@@ -4556,13 +4588,6 @@ iflib_legacy_setup(if_ctx_t ctx, driver_
void *q;
int err;
- /*
- * group taskqueues aren't properly set up until SMP is started
- * so we disable interrupts until we can handle them post
- * SI_SUB_SMP
- */
- IFDI_INTR_DISABLE(ctx);
-
q = &ctx->ifc_rxqs[0];
info = &rxq[0].ifr_filter_info;
gtask = &rxq[0].ifr_task;
Modified: head/sys/sys/gtaskqueue.h
==============================================================================
--- head/sys/sys/gtaskqueue.h Tue Jan 24 12:15:10 2017 (r312695)
+++ head/sys/sys/gtaskqueue.h Tue Jan 24 14:48:32 2017 (r312696)
@@ -81,7 +81,7 @@ int taskqgroup_adjust(struct taskqgroup
extern struct taskqgroup *qgroup_##name
-#if (!defined(SMP) || defined(EARLY_AP_STARTUP))
+#ifdef EARLY_AP_STARTUP
#define TASKQGROUP_DEFINE(name, cnt, stride) \
\
struct taskqgroup *qgroup_##name; \
@@ -95,7 +95,8 @@ taskqgroup_define_##name(void *arg)
\
SYSINIT(taskqgroup_##name, SI_SUB_INIT_IF, SI_ORDER_FIRST, \
taskqgroup_define_##name, NULL)
-#else /* SMP && !EARLY_AP_STARTUP */
+
+#else /* !EARLY_AP_STARTUP */
#define TASKQGROUP_DEFINE(name, cnt, stride) \
\
struct taskqgroup *qgroup_##name; \
@@ -104,15 +105,6 @@ static void
\
taskqgroup_define_##name(void *arg) \
{ \
qgroup_##name = taskqgroup_create(#name); \
- /* Adjustment will be null unless smp_cpus == 1. */ \
- /* \
- * XXX this was intended to fix the smp_cpus == 1 case, but \
- * doesn't actually work for that. It gives thes same strange \
- * panic as adjustment at SI_SUB_INIT_IF:SI_ORDER_ANY for a \
- * device that works with a pure UP kernel. \
- */ \
- /* XXX this code is common now, so should not be ifdefed. */ \
- taskqgroup_adjust(qgroup_##name, (cnt), (stride)); \
} \
\
SYSINIT(taskqgroup_##name, SI_SUB_INIT_IF, SI_ORDER_FIRST, \
@@ -121,17 +113,13 @@ SYSINIT(taskqgroup_##name, SI_SUB_INIT_I
static void \
taskqgroup_adjust_##name(void *arg) \
{ \
- /* \
- * Adjustment when smp_cpus > 1 only works accidentally \
- * (when there is no device interrupt before adjustment). \
- */ \
taskqgroup_adjust(qgroup_##name, (cnt), (stride)); \
} \
\
SYSINIT(taskqgroup_adj_##name, SI_SUB_SMP, SI_ORDER_ANY, \
taskqgroup_adjust_##name, NULL); \
-#endif /* !SMP || EARLY_AP_STARTUP */
+#endif /* EARLY_AP_STARTUP */
TASKQGROUP_DECLARE(net);
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