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Message-Id: <1337335173-3226-8-git-send-email-vipul@chelsio.com>
Date: Fri, 18 May 2012 15:29:30 +0530
From: Vipul Pandya <vipul@...lsio.com>
To: linux-rdma@...r.kernel.org, netdev@...r.kernel.org
Cc: roland@...estorage.com, davem@...emloft.net, divy@...lsio.com,
dm@...lsio.com, kumaras@...lsio.com, swise@...ngridcomputing.com,
Vipul Pandya <vipul@...lsio.com>
Subject: [PATCH 07/10] RDMA/cxgb4: DB Drop Recovery for RDMA and LLD queues.
add module option db_fc_threshold which is the count of active QPs
that trigger automatic db flow control mode.
automatically transition to/from flow control mode when the active qp
count crosses db_fc_theshold.
add more db debugfs stats
on DB DROP event from the LLD, recover all the iwarp queues.
Signed-off-by: Vipul Pandya <vipul@...lsio.com>
Signed-off-by: Steve Wise <swise@...ngridcomputing.com>
---
drivers/infiniband/hw/cxgb4/device.c | 176 ++++++++++++++++++++++++++++++-
drivers/infiniband/hw/cxgb4/iw_cxgb4.h | 24 ++++-
drivers/infiniband/hw/cxgb4/qp.c | 47 ++++++++-
drivers/infiniband/hw/cxgb4/t4.h | 24 +++++
4 files changed, 259 insertions(+), 12 deletions(-)
diff --git a/drivers/infiniband/hw/cxgb4/device.c b/drivers/infiniband/hw/cxgb4/device.c
index 9062ed9..bdb398f 100644
--- a/drivers/infiniband/hw/cxgb4/device.c
+++ b/drivers/infiniband/hw/cxgb4/device.c
@@ -246,6 +246,8 @@ static const struct file_operations stag_debugfs_fops = {
.llseek = default_llseek,
};
+static char *db_state_str[] = {"NORMAL", "FLOW_CONTROL", "RECOVERY"};
+
static int stats_show(struct seq_file *seq, void *v)
{
struct c4iw_dev *dev = seq->private;
@@ -272,6 +274,9 @@ static int stats_show(struct seq_file *seq, void *v)
seq_printf(seq, " DB FULL: %10llu\n", dev->rdev.stats.db_full);
seq_printf(seq, " DB EMPTY: %10llu\n", dev->rdev.stats.db_empty);
seq_printf(seq, " DB DROP: %10llu\n", dev->rdev.stats.db_drop);
+ seq_printf(seq, " DB State: %s Transitions %llu\n",
+ db_state_str[dev->db_state],
+ dev->rdev.stats.db_state_transitions);
return 0;
}
@@ -295,6 +300,7 @@ static ssize_t stats_clear(struct file *file, const char __user *buf,
dev->rdev.stats.db_full = 0;
dev->rdev.stats.db_empty = 0;
dev->rdev.stats.db_drop = 0;
+ dev->rdev.stats.db_state_transitions = 0;
mutex_unlock(&dev->rdev.stats.lock);
return count;
}
@@ -677,8 +683,11 @@ static int disable_qp_db(int id, void *p, void *data)
static void stop_queues(struct uld_ctx *ctx)
{
spin_lock_irq(&ctx->dev->lock);
- ctx->dev->db_state = FLOW_CONTROL;
- idr_for_each(&ctx->dev->qpidr, disable_qp_db, NULL);
+ if (ctx->dev->db_state == NORMAL) {
+ ctx->dev->rdev.stats.db_state_transitions++;
+ ctx->dev->db_state = FLOW_CONTROL;
+ idr_for_each(&ctx->dev->qpidr, disable_qp_db, NULL);
+ }
spin_unlock_irq(&ctx->dev->lock);
}
@@ -693,9 +702,165 @@ static int enable_qp_db(int id, void *p, void *data)
static void resume_queues(struct uld_ctx *ctx)
{
spin_lock_irq(&ctx->dev->lock);
- ctx->dev->db_state = NORMAL;
- idr_for_each(&ctx->dev->qpidr, enable_qp_db, NULL);
+ if (ctx->dev->qpcnt <= db_fc_threshold &&
+ ctx->dev->db_state == FLOW_CONTROL) {
+ ctx->dev->db_state = NORMAL;
+ ctx->dev->rdev.stats.db_state_transitions++;
+ idr_for_each(&ctx->dev->qpidr, enable_qp_db, NULL);
+ }
+ spin_unlock_irq(&ctx->dev->lock);
+}
+
+struct qp_list {
+ unsigned idx;
+ struct c4iw_qp **qps;
+};
+
+static int add_and_ref_qp(int id, void *p, void *data)
+{
+ struct qp_list *qp_listp = data;
+ struct c4iw_qp *qp = p;
+
+ c4iw_qp_add_ref(&qp->ibqp);
+ qp_listp->qps[qp_listp->idx++] = qp;
+ return 0;
+}
+
+static int count_qps(int id, void *p, void *data)
+{
+ unsigned *countp = data;
+ (*countp)++;
+ return 0;
+}
+
+static void deref_qps(struct qp_list qp_list)
+{
+ int idx;
+
+ for (idx = 0; idx < qp_list.idx; idx++)
+ c4iw_qp_rem_ref(&qp_list.qps[idx]->ibqp);
+}
+
+static void recover_lost_dbs(struct uld_ctx *ctx, struct qp_list *qp_list)
+{
+ int idx;
+ int ret;
+
+ for (idx = 0; idx < qp_list->idx; idx++) {
+ struct c4iw_qp *qp = qp_list->qps[idx];
+
+ ret = cxgb4_sync_txq_pidx(qp->rhp->rdev.lldi.ports[0],
+ qp->wq.sq.qid,
+ t4_sq_host_wq_pidx(&qp->wq),
+ t4_sq_wq_size(&qp->wq));
+ if (ret) {
+ printk(KERN_ERR MOD "%s: Fatal error - "
+ "DB overflow recovery failed - "
+ "error syncing SQ qid %u\n",
+ pci_name(ctx->lldi.pdev), qp->wq.sq.qid);
+ return;
+ }
+
+ ret = cxgb4_sync_txq_pidx(qp->rhp->rdev.lldi.ports[0],
+ qp->wq.rq.qid,
+ t4_rq_host_wq_pidx(&qp->wq),
+ t4_rq_wq_size(&qp->wq));
+
+ if (ret) {
+ printk(KERN_ERR MOD "%s: Fatal error - "
+ "DB overflow recovery failed - "
+ "error syncing RQ qid %u\n",
+ pci_name(ctx->lldi.pdev), qp->wq.rq.qid);
+ return;
+ }
+
+ /* Wait for the dbfifo to drain */
+ while (cxgb4_dbfifo_count(qp->rhp->rdev.lldi.ports[0], 1) > 0) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(usecs_to_jiffies(10));
+ }
+ }
+}
+
+static void recover_queues(struct uld_ctx *ctx)
+{
+ int count = 0;
+ struct qp_list qp_list;
+ int ret;
+
+ /* lock out kernel db ringers */
+ mutex_lock(&ctx->dev->db_mutex);
+
+ /* put all queues in to recovery mode */
+ spin_lock_irq(&ctx->dev->lock);
+ ctx->dev->db_state = RECOVERY;
+ ctx->dev->rdev.stats.db_state_transitions++;
+ idr_for_each(&ctx->dev->qpidr, disable_qp_db, NULL);
+ spin_unlock_irq(&ctx->dev->lock);
+
+ /* slow everybody down */
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(usecs_to_jiffies(1000));
+
+ /* Wait for the dbfifo to completely drain. */
+ while (cxgb4_dbfifo_count(ctx->dev->rdev.lldi.ports[0], 1) > 0) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(usecs_to_jiffies(10));
+ }
+
+ /* flush the SGE contexts */
+ ret = cxgb4_flush_eq_cache(ctx->dev->rdev.lldi.ports[0]);
+ if (ret) {
+ printk(KERN_ERR MOD "%s: Fatal error - DB overflow recovery failed\n",
+ pci_name(ctx->lldi.pdev));
+ goto out;
+ }
+
+ /* Count active queues so we can build a list of queues to recover */
+ spin_lock_irq(&ctx->dev->lock);
+ idr_for_each(&ctx->dev->qpidr, count_qps, &count);
+
+ qp_list.qps = kzalloc(count * sizeof *qp_list.qps, GFP_ATOMIC);
+ if (!qp_list.qps) {
+ printk(KERN_ERR MOD "%s: Fatal error - DB overflow recovery failed\n",
+ pci_name(ctx->lldi.pdev));
+ spin_unlock_irq(&ctx->dev->lock);
+ goto out;
+ }
+ qp_list.idx = 0;
+
+ /* add and ref each qp so it doesn't get freed */
+ idr_for_each(&ctx->dev->qpidr, add_and_ref_qp, &qp_list);
+
spin_unlock_irq(&ctx->dev->lock);
+
+ /* now traverse the list in a safe context to recover the db state*/
+ recover_lost_dbs(ctx, &qp_list);
+
+ /* we're almost done! deref the qps and clean up */
+ deref_qps(qp_list);
+ kfree(qp_list.qps);
+
+ /* Wait for the dbfifo to completely drain again */
+ while (cxgb4_dbfifo_count(ctx->dev->rdev.lldi.ports[0], 1) > 0) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(usecs_to_jiffies(10));
+ }
+
+ /* resume the queues */
+ spin_lock_irq(&ctx->dev->lock);
+ if (ctx->dev->qpcnt > db_fc_threshold)
+ ctx->dev->db_state = FLOW_CONTROL;
+ else {
+ ctx->dev->db_state = NORMAL;
+ idr_for_each(&ctx->dev->qpidr, enable_qp_db, NULL);
+ }
+ ctx->dev->rdev.stats.db_state_transitions++;
+ spin_unlock_irq(&ctx->dev->lock);
+
+out:
+ /* start up kernel db ringers again */
+ mutex_unlock(&ctx->dev->db_mutex);
}
static int c4iw_uld_control(void *handle, enum cxgb4_control control, ...)
@@ -716,8 +881,7 @@ static int c4iw_uld_control(void *handle, enum cxgb4_control control, ...)
mutex_unlock(&ctx->dev->rdev.stats.lock);
break;
case CXGB4_CONTROL_DB_DROP:
- printk(KERN_WARNING MOD "%s: Fatal DB DROP\n",
- pci_name(ctx->lldi.pdev));
+ recover_queues(ctx);
mutex_lock(&ctx->dev->rdev.stats.lock);
ctx->dev->rdev.stats.db_drop++;
mutex_unlock(&ctx->dev->rdev.stats.lock);
diff --git a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
index e8b88a0..6818659 100644
--- a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
+++ b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
@@ -120,6 +120,7 @@ struct c4iw_stats {
u64 db_full;
u64 db_empty;
u64 db_drop;
+ u64 db_state_transitions;
};
struct c4iw_rdev {
@@ -212,6 +213,7 @@ struct c4iw_dev {
struct mutex db_mutex;
struct dentry *debugfs_root;
enum db_state db_state;
+ int qpcnt;
};
static inline struct c4iw_dev *to_c4iw_dev(struct ib_device *ibdev)
@@ -271,11 +273,25 @@ static inline int insert_handle_nolock(struct c4iw_dev *rhp, struct idr *idr,
return _insert_handle(rhp, idr, handle, id, 0);
}
-static inline void remove_handle(struct c4iw_dev *rhp, struct idr *idr, u32 id)
+static inline void _remove_handle(struct c4iw_dev *rhp, struct idr *idr,
+ u32 id, int lock)
{
- spin_lock_irq(&rhp->lock);
+ if (lock)
+ spin_lock_irq(&rhp->lock);
idr_remove(idr, id);
- spin_unlock_irq(&rhp->lock);
+ if (lock)
+ spin_unlock_irq(&rhp->lock);
+}
+
+static inline void remove_handle(struct c4iw_dev *rhp, struct idr *idr, u32 id)
+{
+ _remove_handle(rhp, idr, id, 1);
+}
+
+static inline void remove_handle_nolock(struct c4iw_dev *rhp,
+ struct idr *idr, u32 id)
+{
+ _remove_handle(rhp, idr, id, 0);
}
struct c4iw_pd {
@@ -843,5 +859,7 @@ void c4iw_ev_dispatch(struct c4iw_dev *dev, struct t4_cqe *err_cqe);
extern struct cxgb4_client t4c_client;
extern c4iw_handler_func c4iw_handlers[NUM_CPL_CMDS];
extern int c4iw_max_read_depth;
+extern int db_fc_threshold;
+
#endif
diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c
index beec667..ba1343e 100644
--- a/drivers/infiniband/hw/cxgb4/qp.c
+++ b/drivers/infiniband/hw/cxgb4/qp.c
@@ -42,6 +42,11 @@ static int ocqp_support = 1;
module_param(ocqp_support, int, 0644);
MODULE_PARM_DESC(ocqp_support, "Support on-chip SQs (default=1)");
+int db_fc_threshold = 2000;
+module_param(db_fc_threshold, int, 0644);
+MODULE_PARM_DESC(db_fc_threshold, "QP count/threshold that triggers automatic "
+ "db flow control mode (default = 2000)");
+
static void set_state(struct c4iw_qp *qhp, enum c4iw_qp_state state)
{
unsigned long flag;
@@ -1143,13 +1148,19 @@ static int ring_kernel_db(struct c4iw_qp *qhp, u32 qid, u16 inc)
mutex_lock(&qhp->rhp->db_mutex);
do {
- if (cxgb4_dbfifo_count(qhp->rhp->rdev.lldi.ports[0], 1) < 768) {
+
+ /*
+ * The interrupt threshold is dbfifo_int_thresh << 6. So
+ * make sure we don't cross that and generate an interrupt.
+ */
+ if (cxgb4_dbfifo_count(qhp->rhp->rdev.lldi.ports[0], 1) <
+ (qhp->rhp->rdev.lldi.dbfifo_int_thresh << 5)) {
writel(V_QID(qid) | V_PIDX(inc), qhp->wq.db);
break;
}
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(usecs_to_jiffies(delay));
- delay = min(delay << 1, 200000);
+ delay = min(delay << 1, 2000);
} while (1);
mutex_unlock(&qhp->rhp->db_mutex);
return 0;
@@ -1388,6 +1399,14 @@ out:
return ret;
}
+static int enable_qp_db(int id, void *p, void *data)
+{
+ struct c4iw_qp *qp = p;
+
+ t4_enable_wq_db(&qp->wq);
+ return 0;
+}
+
int c4iw_destroy_qp(struct ib_qp *ib_qp)
{
struct c4iw_dev *rhp;
@@ -1405,7 +1424,16 @@ int c4iw_destroy_qp(struct ib_qp *ib_qp)
c4iw_modify_qp(rhp, qhp, C4IW_QP_ATTR_NEXT_STATE, &attrs, 0);
wait_event(qhp->wait, !qhp->ep);
- remove_handle(rhp, &rhp->qpidr, qhp->wq.sq.qid);
+ spin_lock_irq(&rhp->lock);
+ remove_handle_nolock(rhp, &rhp->qpidr, qhp->wq.sq.qid);
+ rhp->qpcnt--;
+ BUG_ON(rhp->qpcnt < 0);
+ if (rhp->qpcnt <= db_fc_threshold && rhp->db_state == FLOW_CONTROL) {
+ rhp->rdev.stats.db_state_transitions++;
+ rhp->db_state = NORMAL;
+ idr_for_each(&rhp->qpidr, enable_qp_db, NULL);
+ }
+ spin_unlock_irq(&rhp->lock);
atomic_dec(&qhp->refcnt);
wait_event(qhp->wait, !atomic_read(&qhp->refcnt));
@@ -1419,6 +1447,14 @@ int c4iw_destroy_qp(struct ib_qp *ib_qp)
return 0;
}
+static int disable_qp_db(int id, void *p, void *data)
+{
+ struct c4iw_qp *qp = p;
+
+ t4_disable_wq_db(&qp->wq);
+ return 0;
+}
+
struct ib_qp *c4iw_create_qp(struct ib_pd *pd, struct ib_qp_init_attr *attrs,
struct ib_udata *udata)
{
@@ -1508,6 +1544,11 @@ struct ib_qp *c4iw_create_qp(struct ib_pd *pd, struct ib_qp_init_attr *attrs,
spin_lock_irq(&rhp->lock);
if (rhp->db_state != NORMAL)
t4_disable_wq_db(&qhp->wq);
+ if (++rhp->qpcnt > db_fc_threshold && rhp->db_state == NORMAL) {
+ rhp->rdev.stats.db_state_transitions++;
+ rhp->db_state = FLOW_CONTROL;
+ idr_for_each(&rhp->qpidr, disable_qp_db, NULL);
+ }
ret = insert_handle_nolock(rhp, &rhp->qpidr, qhp, qhp->wq.sq.qid);
spin_unlock_irq(&rhp->lock);
if (ret)
diff --git a/drivers/infiniband/hw/cxgb4/t4.h b/drivers/infiniband/hw/cxgb4/t4.h
index c0221ee..16f26ab 100644
--- a/drivers/infiniband/hw/cxgb4/t4.h
+++ b/drivers/infiniband/hw/cxgb4/t4.h
@@ -62,6 +62,10 @@ struct t4_status_page {
__be16 pidx;
u8 qp_err; /* flit 1 - sw owns */
u8 db_off;
+ u8 pad;
+ u16 host_wq_pidx;
+ u16 host_cidx;
+ u16 host_pidx;
};
#define T4_EQ_ENTRY_SIZE 64
@@ -375,6 +379,16 @@ static inline void t4_rq_consume(struct t4_wq *wq)
wq->rq.cidx = 0;
}
+static inline u16 t4_rq_host_wq_pidx(struct t4_wq *wq)
+{
+ return wq->rq.queue[wq->rq.size].status.host_wq_pidx;
+}
+
+static inline u16 t4_rq_wq_size(struct t4_wq *wq)
+{
+ return wq->rq.size * T4_RQ_NUM_SLOTS;
+}
+
static inline int t4_sq_onchip(struct t4_sq *sq)
{
return sq->flags & T4_SQ_ONCHIP;
@@ -412,6 +426,16 @@ static inline void t4_sq_consume(struct t4_wq *wq)
wq->sq.cidx = 0;
}
+static inline u16 t4_sq_host_wq_pidx(struct t4_wq *wq)
+{
+ return wq->sq.queue[wq->sq.size].status.host_wq_pidx;
+}
+
+static inline u16 t4_sq_wq_size(struct t4_wq *wq)
+{
+ return wq->sq.size * T4_SQ_NUM_SLOTS;
+}
+
static inline void t4_ring_sq_db(struct t4_wq *wq, u16 inc)
{
wmb();
--
1.7.1
--
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