[patch 15/60] qdio: improve inbound buffer acknowledgement
From: Martin Schwidefsky
Date: Thu Nov 27 2008 - 05:36:42 EST
From: Jan Glauber <jang@xxxxxxxxxxxxxxxxxx>
- Use automatic acknowledgement of incoming buffers in QEBSM mode
- Move ACK for non-QEBSM mode always to the newest buffer to prevent
a race with qdio_stop_polling
- Remove the polling spinlock, the upper layer drivers return new buffers
in the same code path and could not run in parallel
- Don't flood the error log in case of no-target-buffer-empty
- In handle_inbound we check if we would overwrite an ACK'ed buffer, if so
advance the pointer to the oldest ACK'ed buffer so we don't overwrite an
empty buffer in qdio_stop_polling
Signed-off-by: Jan Glauber <jang@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
drivers/s390/cio/qdio.h | 19 ++--
drivers/s390/cio/qdio_debug.c | 7 +
drivers/s390/cio/qdio_main.c | 181 ++++++++++++++++++++++++++--------------
drivers/s390/cio/qdio_perf.c | 2
drivers/s390/cio/qdio_perf.h | 1
drivers/s390/cio/qdio_setup.c | 1
drivers/s390/cio/qdio_thinint.c | 2
7 files changed, 139 insertions(+), 74 deletions(-)
Index: quilt-2.6/drivers/s390/cio/qdio_debug.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio_debug.c
+++ quilt-2.6/drivers/s390/cio/qdio_debug.c
@@ -60,16 +60,18 @@ static int qstat_show(struct seq_file *m
if (!q)
return 0;
- seq_printf(m, "device state indicator: %d\n", *q->irq_ptr->dsci);
+ seq_printf(m, "device state indicator: %d\n", *(u32 *)q->irq_ptr->dsci);
seq_printf(m, "nr_used: %d\n", atomic_read(&q->nr_buf_used));
seq_printf(m, "ftc: %d\n", q->first_to_check);
seq_printf(m, "last_move_ftc: %d\n", q->last_move_ftc);
seq_printf(m, "polling: %d\n", q->u.in.polling);
+ seq_printf(m, "ack count: %d\n", q->u.in.ack_count);
seq_printf(m, "slsb buffer states:\n");
+ seq_printf(m, "|0 |8 |16 |24 |32 |40 |48 |56 63|\n");
qdio_siga_sync_q(q);
for (i = 0; i < QDIO_MAX_BUFFERS_PER_Q; i++) {
- get_buf_state(q, i, &state);
+ get_buf_state(q, i, &state, 0);
switch (state) {
case SLSB_P_INPUT_NOT_INIT:
case SLSB_P_OUTPUT_NOT_INIT:
@@ -101,6 +103,7 @@ static int qstat_show(struct seq_file *m
seq_printf(m, "\n");
}
seq_printf(m, "\n");
+ seq_printf(m, "|64 |72 |80 |88 |96 |104 |112 | 127|\n");
return 0;
}
Index: quilt-2.6/drivers/s390/cio/qdio.h
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio.h
+++ quilt-2.6/drivers/s390/cio/qdio.h
@@ -112,12 +112,12 @@ static inline int do_sqbs(u64 token, uns
}
static inline int do_eqbs(u64 token, unsigned char *state, int queue,
- int *start, int *count)
+ int *start, int *count, int ack)
{
register unsigned long _ccq asm ("0") = *count;
register unsigned long _token asm ("1") = token;
unsigned long _queuestart = ((unsigned long)queue << 32) | *start;
- unsigned long _state = 0;
+ unsigned long _state = (unsigned long)ack << 63;
asm volatile(
" .insn rrf,0xB99c0000,%1,%2,0,0"
@@ -134,7 +134,7 @@ static inline int do_eqbs(u64 token, uns
static inline int do_sqbs(u64 token, unsigned char state, int queue,
int *start, int *count) { return 0; }
static inline int do_eqbs(u64 token, unsigned char *state, int queue,
- int *start, int *count) { return 0; }
+ int *start, int *count, int ack) { return 0; }
#endif /* CONFIG_64BIT */
struct qdio_irq;
@@ -187,11 +187,11 @@ struct qdio_input_q {
/* input buffer acknowledgement flag */
int polling;
+ /* how much sbals are acknowledged with qebsm */
+ int ack_count;
+
/* last time of noticing incoming data */
u64 timestamp;
-
- /* lock for clearing the acknowledgement */
- spinlock_t lock;
};
struct qdio_output_q {
@@ -351,10 +351,13 @@ static inline unsigned long long get_use
((bufnr + 1) & QDIO_MAX_BUFFERS_MASK)
#define add_buf(bufnr, inc) \
((bufnr + inc) & QDIO_MAX_BUFFERS_MASK)
+#define sub_buf(bufnr, dec) \
+ ((bufnr - dec) & QDIO_MAX_BUFFERS_MASK)
/* prototypes for thin interrupt */
void qdio_sync_after_thinint(struct qdio_q *q);
-int get_buf_state(struct qdio_q *q, unsigned int bufnr, unsigned char *state);
+int get_buf_state(struct qdio_q *q, unsigned int bufnr, unsigned char *state,
+ int auto_ack);
void qdio_check_outbound_after_thinint(struct qdio_q *q);
int qdio_inbound_q_moved(struct qdio_q *q);
void qdio_kick_inbound_handler(struct qdio_q *q);
@@ -388,6 +391,8 @@ int qdio_setup_irq(struct qdio_initializ
void qdio_print_subchannel_info(struct qdio_irq *irq_ptr,
struct ccw_device *cdev);
void qdio_release_memory(struct qdio_irq *irq_ptr);
+int qdio_setup_create_sysfs(struct ccw_device *cdev);
+void qdio_setup_destroy_sysfs(struct ccw_device *cdev);
int qdio_setup_init(void);
void qdio_setup_exit(void);
Index: quilt-2.6/drivers/s390/cio/qdio_main.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio_main.c
+++ quilt-2.6/drivers/s390/cio/qdio_main.c
@@ -112,12 +112,13 @@ static inline int qdio_check_ccq(struct
* @state: state of the extracted buffers
* @start: buffer number to start at
* @count: count of buffers to examine
+ * @auto_ack: automatically acknowledge buffers
*
* Returns the number of successfull extracted equal buffer states.
* Stops processing if a state is different from the last buffers state.
*/
static int qdio_do_eqbs(struct qdio_q *q, unsigned char *state,
- int start, int count)
+ int start, int count, int auto_ack)
{
unsigned int ccq = 0;
int tmp_count = count, tmp_start = start;
@@ -130,7 +131,8 @@ static int qdio_do_eqbs(struct qdio_q *q
if (!q->is_input_q)
nr += q->irq_ptr->nr_input_qs;
again:
- ccq = do_eqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count);
+ ccq = do_eqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count,
+ auto_ack);
rc = qdio_check_ccq(q, ccq);
/* At least one buffer was processed, return and extract the remaining
@@ -176,6 +178,9 @@ static int qdio_do_sqbs(struct qdio_q *q
int nr = q->nr;
int rc;
+ if (!count)
+ return 0;
+
BUG_ON(!q->irq_ptr->sch_token);
qdio_perf_stat_inc(&perf_stats.debug_sqbs_all);
@@ -203,7 +208,8 @@ again:
/* returns number of examined buffers and their common state in *state */
static inline int get_buf_states(struct qdio_q *q, unsigned int bufnr,
- unsigned char *state, unsigned int count)
+ unsigned char *state, unsigned int count,
+ int auto_ack)
{
unsigned char __state = 0;
int i;
@@ -212,7 +218,7 @@ static inline int get_buf_states(struct
BUG_ON(count > QDIO_MAX_BUFFERS_PER_Q);
if (is_qebsm(q))
- return qdio_do_eqbs(q, state, bufnr, count);
+ return qdio_do_eqbs(q, state, bufnr, count, auto_ack);
for (i = 0; i < count; i++) {
if (!__state)
@@ -226,9 +232,9 @@ static inline int get_buf_states(struct
}
inline int get_buf_state(struct qdio_q *q, unsigned int bufnr,
- unsigned char *state)
+ unsigned char *state, int auto_ack)
{
- return get_buf_states(q, bufnr, state, 1);
+ return get_buf_states(q, bufnr, state, 1, auto_ack);
}
/* wrap-around safe setting of slsb states, returns number of changed buffers */
@@ -376,29 +382,91 @@ void qdio_sync_after_thinint(struct qdio
inline void qdio_stop_polling(struct qdio_q *q)
{
- spin_lock_bh(&q->u.in.lock);
- if (!q->u.in.polling) {
- spin_unlock_bh(&q->u.in.lock);
+ if (!q->u.in.polling)
return;
- }
+
q->u.in.polling = 0;
qdio_perf_stat_inc(&perf_stats.debug_stop_polling);
/* show the card that we are not polling anymore */
- set_buf_state(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT);
- spin_unlock_bh(&q->u.in.lock);
+ if (is_qebsm(q)) {
+ set_buf_states(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT,
+ q->u.in.ack_count);
+ q->u.in.ack_count = 0;
+ } else
+ set_buf_state(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT);
}
-static void announce_buffer_error(struct qdio_q *q)
+static void announce_buffer_error(struct qdio_q *q, int count)
{
+ q->qdio_error = QDIO_ERROR_SLSB_STATE;
+
+ /* special handling for no target buffer empty */
+ if ((!q->is_input_q &&
+ (q->sbal[q->first_to_check]->element[15].flags & 0xff) == 0x10)) {
+ qdio_perf_stat_inc(&perf_stats.outbound_target_full);
+ DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "OUTFULL FTC:%3d",
+ q->first_to_check);
+ return;
+ }
+
DBF_ERROR("%4x BUF ERROR", SCH_NO(q));
DBF_ERROR((q->is_input_q) ? "IN:%2d" : "OUT:%2d", q->nr);
- DBF_ERROR("FTC:%3d", q->first_to_check);
+ DBF_ERROR("FTC:%3d C:%3d", q->first_to_check, count);
DBF_ERROR("F14:%2x F15:%2x",
q->sbal[q->first_to_check]->element[14].flags & 0xff,
q->sbal[q->first_to_check]->element[15].flags & 0xff);
+}
- q->qdio_error = QDIO_ERROR_SLSB_STATE;
+static inline void inbound_primed(struct qdio_q *q, int count)
+{
+ int new;
+
+ DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in prim: %3d", count);
+
+ /* for QEBSM the ACK was already set by EQBS */
+ if (is_qebsm(q)) {
+ if (!q->u.in.polling) {
+ q->u.in.polling = 1;
+ q->u.in.ack_count = count;
+ q->last_move_ftc = q->first_to_check;
+ return;
+ }
+
+ /* delete the previous ACK's */
+ set_buf_states(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT,
+ q->u.in.ack_count);
+ q->u.in.ack_count = count;
+ q->last_move_ftc = q->first_to_check;
+ return;
+ }
+
+ /*
+ * ACK the newest buffer. The ACK will be removed in qdio_stop_polling
+ * or by the next inbound run.
+ */
+ new = add_buf(q->first_to_check, count - 1);
+ if (q->u.in.polling) {
+ /* reset the previous ACK but first set the new one */
+ set_buf_state(q, new, SLSB_P_INPUT_ACK);
+ set_buf_state(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT);
+ }
+ else {
+ q->u.in.polling = 1;
+ set_buf_state(q, q->first_to_check, SLSB_P_INPUT_ACK);
+ }
+
+ q->last_move_ftc = new;
+ count--;
+ if (!count)
+ return;
+
+ /*
+ * Need to change all PRIMED buffers to NOT_INIT, otherwise
+ * we're loosing initiative in the thinint code.
+ */
+ set_buf_states(q, next_buf(q->first_to_check), SLSB_P_INPUT_NOT_INIT,
+ count);
}
static int get_inbound_buffer_frontier(struct qdio_q *q)
@@ -407,13 +475,6 @@ static int get_inbound_buffer_frontier(s
unsigned char state;
/*
- * If we still poll don't update last_move_ftc, keep the
- * previously ACK buffer there.
- */
- if (!q->u.in.polling)
- q->last_move_ftc = q->first_to_check;
-
- /*
* Don't check 128 buffers, as otherwise qdio_inbound_q_moved
* would return 0.
*/
@@ -433,34 +494,13 @@ check_next:
if (q->first_to_check == stop)
goto out;
- count = get_buf_states(q, q->first_to_check, &state, count);
+ count = get_buf_states(q, q->first_to_check, &state, count, 1);
if (!count)
goto out;
switch (state) {
case SLSB_P_INPUT_PRIMED:
- DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in prim: %3d", count);
-
- /*
- * Only ACK the first buffer. The ACK will be removed in
- * qdio_stop_polling.
- */
- if (q->u.in.polling)
- state = SLSB_P_INPUT_NOT_INIT;
- else {
- q->u.in.polling = 1;
- state = SLSB_P_INPUT_ACK;
- }
- set_buf_state(q, q->first_to_check, state);
-
- /*
- * Need to change all PRIMED buffers to NOT_INIT, otherwise
- * we're loosing initiative in the thinint code.
- */
- if (count > 1)
- set_buf_states(q, next_buf(q->first_to_check),
- SLSB_P_INPUT_NOT_INIT, count - 1);
-
+ inbound_primed(q, count);
/*
* No siga-sync needed for non-qebsm here, as the inbound queue
* will be synced on the next siga-r, resp.
@@ -470,7 +510,7 @@ check_next:
atomic_sub(count, &q->nr_buf_used);
goto check_next;
case SLSB_P_INPUT_ERROR:
- announce_buffer_error(q);
+ announce_buffer_error(q, count);
/* process the buffer, the upper layer will take care of it */
q->first_to_check = add_buf(q->first_to_check, count);
atomic_sub(count, &q->nr_buf_used);
@@ -519,7 +559,7 @@ static int qdio_inbound_q_done(struct qd
*/
qdio_siga_sync_q(q);
- get_buf_state(q, q->first_to_check, &state);
+ get_buf_state(q, q->first_to_check, &state, 0);
if (state == SLSB_P_INPUT_PRIMED)
/* we got something to do */
return 0;
@@ -622,7 +662,7 @@ check_next:
if (q->first_to_check == stop)
return q->first_to_check;
- count = get_buf_states(q, q->first_to_check, &state, count);
+ count = get_buf_states(q, q->first_to_check, &state, count, 0);
if (!count)
return q->first_to_check;
@@ -641,7 +681,7 @@ check_next:
break;
goto check_next;
case SLSB_P_OUTPUT_ERROR:
- announce_buffer_error(q);
+ announce_buffer_error(q, count);
/* process the buffer, the upper layer will take care of it */
q->first_to_check = add_buf(q->first_to_check, count);
atomic_sub(count, &q->nr_buf_used);
@@ -1457,23 +1497,38 @@ static inline int buf_in_between(int buf
static void handle_inbound(struct qdio_q *q, unsigned int callflags,
int bufnr, int count)
{
- unsigned long flags;
- int used, rc;
+ int used, rc, diff;
- /*
- * do_QDIO could run in parallel with the queue tasklet so the
- * upper-layer programm could empty the ACK'ed buffer here.
- * If that happens we must clear the polling flag, otherwise
- * qdio_stop_polling() could set the buffer to NOT_INIT after
- * it was set to EMPTY which would kill us.
- */
- spin_lock_irqsave(&q->u.in.lock, flags);
- if (q->u.in.polling)
- if (buf_in_between(q->last_move_ftc, bufnr, count))
+ if (!q->u.in.polling)
+ goto set;
+
+ /* protect against stop polling setting an ACK for an emptied slsb */
+ if (count == QDIO_MAX_BUFFERS_PER_Q) {
+ /* overwriting everything, just delete polling status */
+ q->u.in.polling = 0;
+ q->u.in.ack_count = 0;
+ goto set;
+ } else if (buf_in_between(q->last_move_ftc, bufnr, count)) {
+ if (is_qebsm(q)) {
+ /* partial overwrite, just update last_move_ftc */
+ diff = add_buf(bufnr, count);
+ diff = sub_buf(diff, q->last_move_ftc);
+ q->u.in.ack_count -= diff;
+ if (q->u.in.ack_count <= 0) {
+ q->u.in.polling = 0;
+ q->u.in.ack_count = 0;
+ /* TODO: must we set last_move_ftc to something meaningful? */
+ goto set;
+ }
+ q->last_move_ftc = add_buf(q->last_move_ftc, diff);
+ }
+ else
+ /* the only ACK will be deleted, so stop polling */
q->u.in.polling = 0;
+ }
+set:
count = set_buf_states(q, bufnr, SLSB_CU_INPUT_EMPTY, count);
- spin_unlock_irqrestore(&q->u.in.lock, flags);
used = atomic_add_return(count, &q->nr_buf_used) - count;
BUG_ON(used + count > QDIO_MAX_BUFFERS_PER_Q);
@@ -1541,7 +1596,7 @@ static void handle_outbound(struct qdio_
}
/* try to fast requeue buffers */
- get_buf_state(q, prev_buf(bufnr), &state);
+ get_buf_state(q, prev_buf(bufnr), &state, 0);
if (state != SLSB_CU_OUTPUT_PRIMED)
qdio_kick_outbound_q(q);
else {
Index: quilt-2.6/drivers/s390/cio/qdio_perf.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio_perf.c
+++ quilt-2.6/drivers/s390/cio/qdio_perf.c
@@ -74,6 +74,8 @@ static int qdio_perf_proc_show(struct se
seq_printf(m, "\n");
seq_printf(m, "Number of fast requeues (outg. SBAL w/o SIGA)\t: %li\n",
(long)atomic_long_read(&perf_stats.fast_requeue));
+ seq_printf(m, "Number of outbound target full condition\t: %li\n",
+ (long)atomic_long_read(&perf_stats.outbound_target_full));
seq_printf(m, "Number of outbound tasklet mod_timer calls\t: %li\n",
(long)atomic_long_read(&perf_stats.debug_tl_out_timer));
seq_printf(m, "Number of stop polling calls\t\t\t: %li\n",
Index: quilt-2.6/drivers/s390/cio/qdio_perf.h
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio_perf.h
+++ quilt-2.6/drivers/s390/cio/qdio_perf.h
@@ -36,6 +36,7 @@ struct qdio_perf_stats {
atomic_long_t inbound_handler;
atomic_long_t outbound_handler;
atomic_long_t fast_requeue;
+ atomic_long_t outbound_target_full;
/* for debugging */
atomic_long_t debug_tl_out_timer;
Index: quilt-2.6/drivers/s390/cio/qdio_setup.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio_setup.c
+++ quilt-2.6/drivers/s390/cio/qdio_setup.c
@@ -167,7 +167,6 @@ static void setup_queues(struct qdio_irq
setup_queues_misc(q, irq_ptr, qdio_init->input_handler, i);
q->is_input_q = 1;
- spin_lock_init(&q->u.in.lock);
setup_storage_lists(q, irq_ptr, input_sbal_array, i);
input_sbal_array += QDIO_MAX_BUFFERS_PER_Q;
Index: quilt-2.6/drivers/s390/cio/qdio_thinint.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio_thinint.c
+++ quilt-2.6/drivers/s390/cio/qdio_thinint.c
@@ -131,7 +131,7 @@ static inline int tiqdio_inbound_q_done(
return 1;
qdio_siga_sync_q(q);
- get_buf_state(q, q->first_to_check, &state);
+ get_buf_state(q, q->first_to_check, &state, 0);
if (state == SLSB_P_INPUT_PRIMED)
/* more work coming */
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
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