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Merge of the trunk's r3214-3215

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git-svn-id: http://svn.code.sf.net/p/scst/svn/branches/2.0.0.x@3216 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Vladislav Bolkhovitin
2011-01-13 19:15:50 +00:00
parent d906b4ab62
commit 7dba2398d2
6 changed files with 178 additions and 42 deletions
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8
scst/README
View File

@@ -389,6 +389,14 @@ following entries:
- handlers - this is a root subdirectory for all SCST dev handlers
- max_tasklet_cmd - specifies how many commands at max can be queued in
the SCST core simultaneously from all connected initiators to allow
processing commands in soft-IRQ context in tasklets. If the count of
the commands exceeds this value, then all of them will be processed
only in threads. This is to to prevent possible starvation under
heavy load and in some cases to improve performance by more evenly
spreading load over available CPUs.
- sgv - this is a root subdirectory for all SCST SGV caches
- targets - this is a root subdirectory for all SCST targets

8
scst/README_in-tree
View File

@@ -257,6 +257,14 @@ following entries:
- handlers - this is a root subdirectory for all SCST dev handlers
- max_tasklet_cmd - specifies how many commands at max can be queued in
the SCST core simultaneously from all connected initiators to allow
processing commands in soft-IRQ context in tasklets. If the count of
the commands exceeds this value, then all of them will be processed
only in threads. This is to to prevent possible starvation under
heavy load and in some cases to improve performance by more evenly
spreading load over available CPUs.
- sgv - this is a root subdirectory for all SCST SGV caches
- targets - this is a root subdirectory for all SCST targets

2
scst/src/scst_main.c
View File

@@ -127,6 +127,8 @@ struct kmem_cache *scst_cmd_cachep;
unsigned long scst_trace_flag;
#endif
int scst_max_tasklet_cmd = SCST_DEF_MAX_TASKLET_CMD;
unsigned long scst_flags;
atomic_t scst_cmd_count;

3
scst/src/scst_priv.h
View File

@@ -169,6 +169,9 @@ extern struct scst_acg *scst_default_acg;
extern unsigned int scst_setup_id;
#endif
#define SCST_DEF_MAX_TASKLET_CMD 20
extern int scst_max_tasklet_cmd;
extern spinlock_t scst_init_lock;
extern struct list_head scst_init_cmd_list;
extern wait_queue_head_t scst_init_cmd_list_waitQ;

44
scst/src/scst_sysfs.c
View File

@@ -4458,6 +4458,49 @@ static struct kobj_attribute scst_setup_id_attr =
__ATTR(setup_id, S_IRUGO | S_IWUSR, scst_setup_id_show,
scst_setup_id_store);
static ssize_t scst_max_tasklet_cmd_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
int count;
TRACE_ENTRY();
count = sprintf(buf, "%d\n%s\n", scst_max_tasklet_cmd,
(scst_max_tasklet_cmd == SCST_DEF_MAX_TASKLET_CMD)
? "" : SCST_SYSFS_KEY_MARK);
TRACE_EXIT();
return count;
}
static ssize_t scst_max_tasklet_cmd_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
int res;
unsigned long val;
TRACE_ENTRY();
res = strict_strtoul(buf, 0, &val);
if (res != 0) {
PRINT_ERROR("strict_strtoul() for %s failed: %d ", buf, res);
goto out;
}
scst_max_tasklet_cmd = val;
PRINT_INFO("Changed scst_max_tasklet_cmd to %d", scst_max_tasklet_cmd);
res = count;
out:
TRACE_EXIT_RES(res);
return res;
}
static struct kobj_attribute scst_max_tasklet_cmd_attr =
__ATTR(max_tasklet_cmd, S_IRUGO | S_IWUSR, scst_max_tasklet_cmd_show,
scst_max_tasklet_cmd_store);
#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
static struct kobj_attribute scst_trace_level_attr =
__ATTR(trace_level, S_IRUGO | S_IWUSR, scst_main_trace_level_show,
@@ -4474,6 +4517,7 @@ static struct kobj_attribute scst_last_sysfs_mgmt_res_attr =
static struct attribute *scst_sysfs_root_default_attrs[] = {
&scst_threads_attr.attr,
&scst_setup_id_attr.attr,
&scst_max_tasklet_cmd_attr.attr,
#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
&scst_trace_level_attr.attr,
#endif

155
scst/src/scst_targ.c
View File

@@ -87,13 +87,24 @@ static inline void scst_schedule_tasklet(struct scst_cmd *cmd)
struct scst_tasklet *t = &scst_tasklets[smp_processor_id()];
unsigned long flags;
spin_lock_irqsave(&t->tasklet_lock, flags);
TRACE_DBG("Adding cmd %p to tasklet %d cmd list", cmd,
smp_processor_id());
list_add_tail(&cmd->cmd_list_entry, &t->tasklet_cmd_list);
spin_unlock_irqrestore(&t->tasklet_lock, flags);
if (atomic_read(&scst_cmd_count) <= scst_max_tasklet_cmd) {
spin_lock_irqsave(&t->tasklet_lock, flags);
TRACE_DBG("Adding cmd %p to tasklet %d cmd list", cmd,
smp_processor_id());
list_add_tail(&cmd->cmd_list_entry, &t->tasklet_cmd_list);
spin_unlock_irqrestore(&t->tasklet_lock, flags);
tasklet_schedule(&t->tasklet);
tasklet_schedule(&t->tasklet);
} else {
spin_lock_irqsave(&cmd->cmd_threads->cmd_list_lock, flags);
TRACE_DBG("Too many tasklet commands (%d), adding cmd %p to "
"active cmd list", atomic_read(&scst_cmd_count), cmd);
list_add_tail(&cmd->cmd_list_entry,
&cmd->cmd_threads->active_cmd_list);
wake_up(&cmd->cmd_threads->cmd_list_waitQ);
spin_unlock_irqrestore(&cmd->cmd_threads->cmd_list_lock, flags);
}
return;
}
/**
@@ -204,10 +215,14 @@ static int scst_init_cmd(struct scst_cmd *cmd, enum scst_exec_context *context)
#endif
/* Small context optimization */
if (((*context == SCST_CONTEXT_TASKLET) ||
(*context == SCST_CONTEXT_DIRECT_ATOMIC)) &&
scst_cmd_is_expected_set(cmd)) {
if (cmd->expected_data_direction & SCST_DATA_WRITE) {
if ((*context == SCST_CONTEXT_TASKLET) ||
(*context == SCST_CONTEXT_DIRECT_ATOMIC)) {
/*
* If any data_direction not set, it's SCST_DATA_UNKNOWN,
* which is 0, so we can safely | them
*/
BUILD_BUG_ON(SCST_DATA_UNKNOWN != 0);
if ((cmd->data_direction | cmd->expected_data_direction) & SCST_DATA_WRITE) {
if (!test_bit(SCST_TGT_DEV_AFTER_INIT_WR_ATOMIC,
&cmd->tgt_dev->tgt_dev_flags))
*context = SCST_CONTEXT_THREAD;
@@ -297,6 +312,7 @@ void scst_cmd_init_done(struct scst_cmd *cmd,
PRINT_ERROR("Wrong context %d in IRQ from target %s, use "
"SCST_CONTEXT_THREAD instead", pref_context,
cmd->tgtt->name);
dump_stack();
pref_context = SCST_CONTEXT_THREAD;
}
#endif
@@ -371,14 +387,6 @@ active:
scst_schedule_tasklet(cmd);
break;
case SCST_CONTEXT_DIRECT:
scst_process_active_cmd(cmd, false);
break;
case SCST_CONTEXT_DIRECT_ATOMIC:
scst_process_active_cmd(cmd, true);
break;
default:
PRINT_ERROR("Context %x is undefined, using the thread one",
pref_context);
@@ -395,6 +403,14 @@ active:
wake_up(&cmd->cmd_threads->cmd_list_waitQ);
spin_unlock_irqrestore(&cmd->cmd_threads->cmd_list_lock, flags);
break;
case SCST_CONTEXT_DIRECT:
scst_process_active_cmd(cmd, false);
break;
case SCST_CONTEXT_DIRECT_ATOMIC:
scst_process_active_cmd(cmd, true);
break;
}
out:
@@ -508,7 +524,7 @@ static int scst_parse_cmd(struct scst_cmd *cmd)
* It shouldn't be because of the SCST_TGT_DEV_AFTER_*
* optimization.
*/
TRACE_DBG("Dev handler %s parse() needs thread "
TRACE_MGMT_DBG("Dev handler %s parse() needs thread "
"context, rescheduling", dev->handler->name);
res = SCST_CMD_STATE_RES_NEED_THREAD;
goto out;
@@ -806,6 +822,21 @@ set_res:
if (unlikely(cmd->completed))
goto out_done;
#ifndef CONFIG_SCST_TEST_IO_IN_SIRQ
/*
* We can't allow atomic command on the exec stages. It shouldn't
* be because of the SCST_TGT_DEV_AFTER_* optimization, but during
* parsing data_direction can change, so we need to recheck.
*/
if (unlikely(scst_cmd_atomic(cmd) &&
!(cmd->data_direction & SCST_DATA_WRITE))) {
TRACE_DBG_FLAG(TRACE_DEBUG|TRACE_MINOR, "Atomic context and "
"non-WRITE data direction, rescheduling (cmd %p)", cmd);
res = SCST_CMD_STATE_RES_NEED_THREAD;
goto out;
}
#endif
out:
TRACE_EXIT_HRES(res);
return res;
@@ -879,7 +910,7 @@ static int scst_prepare_space(struct scst_cmd *cmd)
* It shouldn't be because of the SCST_TGT_DEV_AFTER_*
* optimization.
*/
TRACE_DBG("Dev handler %s alloc_data_buf() needs "
TRACE_MGMT_DBG("Dev handler %s alloc_data_buf() needs "
"thread context, rescheduling",
dev->handler->name);
res = SCST_CMD_STATE_RES_NEED_THREAD;
@@ -1069,6 +1100,7 @@ void scst_restart_cmd(struct scst_cmd *cmd, int status,
PRINT_ERROR("Wrong context %d in IRQ from target %s, use "
"SCST_CONTEXT_THREAD instead", pref_context,
cmd->tgtt->name);
dump_stack();
pref_context = SCST_CONTEXT_THREAD;
}
#endif
@@ -1095,6 +1127,7 @@ void scst_restart_cmd(struct scst_cmd *cmd, int status,
case SCST_PREPROCESS_STATUS_ERROR_SENSE_SET:
scst_set_cmd_abnormal_done_state(cmd);
pref_context = SCST_CONTEXT_THREAD;
break;
case SCST_PREPROCESS_STATUS_ERROR_FATAL:
@@ -1105,12 +1138,14 @@ void scst_restart_cmd(struct scst_cmd *cmd, int status,
scst_set_cmd_error(cmd,
SCST_LOAD_SENSE(scst_sense_hardw_error));
scst_set_cmd_abnormal_done_state(cmd);
pref_context = SCST_CONTEXT_THREAD;
break;
default:
PRINT_ERROR("%s() received unknown status %x", __func__,
status);
scst_set_cmd_abnormal_done_state(cmd);
pref_context = SCST_CONTEXT_THREAD;
break;
}
@@ -1135,7 +1170,15 @@ static int scst_rdy_to_xfer(struct scst_cmd *cmd)
if ((tgtt->rdy_to_xfer == NULL) || unlikely(cmd->internal)) {
cmd->state = SCST_CMD_STATE_TGT_PRE_EXEC;
res = SCST_CMD_STATE_RES_CONT_SAME;
#ifndef CONFIG_SCST_TEST_IO_IN_SIRQ
/* We can't allow atomic command on the exec stages */
if (scst_cmd_atomic(cmd)) {
TRACE_DBG("NULL rdy_to_xfer() and atomic context, "
"rescheduling (cmd %p)", cmd);
res = SCST_CMD_STATE_RES_NEED_THREAD;
} else
#endif
res = SCST_CMD_STATE_RES_CONT_SAME;
goto out;
}
@@ -1144,8 +1187,8 @@ static int scst_rdy_to_xfer(struct scst_cmd *cmd)
* It shouldn't be because of the SCST_TGT_DEV_AFTER_*
* optimization.
*/
TRACE_DBG("Target driver %s rdy_to_xfer() needs thread "
"context, rescheduling", tgtt->name);
TRACE_MGMT_DBG("Target driver %s rdy_to_xfer() needs thread "
"context, rescheduling", tgtt->name);
res = SCST_CMD_STATE_RES_NEED_THREAD;
goto out;
}
@@ -1243,6 +1286,9 @@ static void scst_process_redirect_cmd(struct scst_cmd *cmd,
TRACE_DBG("Context: %x", context);
if (check_retries)
scst_check_retries(tgt);
if (context == SCST_CONTEXT_SAME)
context = scst_cmd_atomic(cmd) ? SCST_CONTEXT_DIRECT_ATOMIC :
SCST_CONTEXT_DIRECT;
@@ -1253,18 +1299,18 @@ static void scst_process_redirect_cmd(struct scst_cmd *cmd,
break;
case SCST_CONTEXT_DIRECT:
if (check_retries)
scst_check_retries(tgt);
scst_process_active_cmd(cmd, false);
break;
case SCST_CONTEXT_TASKLET:
scst_schedule_tasklet(cmd);
break;
default:
PRINT_ERROR("Context %x is unknown, using the thread one",
context);
/* go through */
case SCST_CONTEXT_THREAD:
if (check_retries)
scst_check_retries(tgt);
spin_lock_irqsave(&cmd->cmd_threads->cmd_list_lock, flags);
TRACE_DBG("Adding cmd %p to active cmd list", cmd);
if (unlikely(cmd->queue_type == SCST_CMD_QUEUE_HEAD_OF_QUEUE))
@@ -1276,12 +1322,6 @@ static void scst_process_redirect_cmd(struct scst_cmd *cmd,
wake_up(&cmd->cmd_threads->cmd_list_waitQ);
spin_unlock_irqrestore(&cmd->cmd_threads->cmd_list_lock, flags);
break;
case SCST_CONTEXT_TASKLET:
if (check_retries)
scst_check_retries(tgt);
scst_schedule_tasklet(cmd);
break;
}
TRACE_EXIT();
@@ -1320,6 +1360,7 @@ void scst_rx_data(struct scst_cmd *cmd, int status,
PRINT_ERROR("Wrong context %d in IRQ from target %s, use "
"SCST_CONTEXT_THREAD instead", pref_context,
cmd->tgtt->name);
dump_stack();
pref_context = SCST_CONTEXT_THREAD;
}
#endif
@@ -1367,6 +1408,7 @@ void scst_rx_data(struct scst_cmd *cmd, int status,
case SCST_RX_STATUS_ERROR_SENSE_SET:
scst_set_cmd_abnormal_done_state(cmd);
pref_context = SCST_CONTEXT_THREAD;
break;
case SCST_RX_STATUS_ERROR_FATAL:
@@ -1376,12 +1418,14 @@ void scst_rx_data(struct scst_cmd *cmd, int status,
scst_set_cmd_error(cmd,
SCST_LOAD_SENSE(scst_sense_hardw_error));
scst_set_cmd_abnormal_done_state(cmd);
pref_context = SCST_CONTEXT_THREAD;
break;
default:
PRINT_ERROR("scst_rx_data() received unknown status %x",
status);
scst_set_cmd_abnormal_done_state(cmd);
pref_context = SCST_CONTEXT_THREAD;
break;
}
@@ -2601,7 +2645,7 @@ out_complete:
if (ctx_changed)
scst_reset_io_context(cmd->tgt_dev, old_ctx);
TRACE_EXIT();
TRACE_EXIT_RES(res);
return res;
out_error:
@@ -2633,7 +2677,6 @@ static inline int scst_real_exec(struct scst_cmd *cmd)
__scst_cmd_get(cmd);
res = scst_do_real_exec(cmd);
if (likely(res == SCST_EXEC_COMPLETED)) {
scst_post_exec_sn(cmd, true);
if (cmd->dev->scsi_dev != NULL)
@@ -3030,8 +3073,14 @@ static int scst_pre_dev_done(struct scst_cmd *cmd)
SCST_LOAD_SENSE(scst_sense_hardw_error));
}
goto out;
} else if (unlikely(scst_check_sense(cmd)))
} else if (unlikely(scst_check_sense(cmd))) {
/*
* We can't allow atomic command on the exec stages, so
* restart to the thread
*/
res = SCST_CMD_STATE_RES_NEED_THREAD;
goto out;
}
if (likely(scsi_status_is_good(cmd->status))) {
unsigned char type = cmd->dev->type;
@@ -3275,8 +3324,8 @@ static int scst_dev_done(struct scst_cmd *cmd)
* It shouldn't be because of the SCST_TGT_DEV_AFTER_*
* optimization.
*/
TRACE_DBG("Dev handler %s dev_done() needs thread "
"context, rescheduling", dev->handler->name);
TRACE_MGMT_DBG("Dev handler %s dev_done() needs thread "
"context, rescheduling", dev->handler->name);
res = SCST_CMD_STATE_RES_NEED_THREAD;
goto out;
}
@@ -3345,6 +3394,24 @@ static int scst_dev_done(struct scst_cmd *cmd)
if (unlikely(cmd->internal))
cmd->state = SCST_CMD_STATE_FINISHED_INTERNAL;
#ifndef CONFIG_SCST_TEST_IO_IN_SIRQ
if (cmd->state != SCST_CMD_STATE_PRE_XMIT_RESP) {
/* We can't allow atomic command on the exec stages */
if (scst_cmd_atomic(cmd)) {
switch (state) {
case SCST_CMD_STATE_TGT_PRE_EXEC:
case SCST_CMD_STATE_SEND_FOR_EXEC:
case SCST_CMD_STATE_LOCAL_EXEC:
case SCST_CMD_STATE_REAL_EXEC:
TRACE_DBG("Atomic context and redirect, "
"rescheduling (cmd %p)", cmd);
res = SCST_CMD_STATE_RES_NEED_THREAD;
break;
}
}
}
#endif
out:
TRACE_EXIT_HRES(res);
return res;
@@ -3443,8 +3510,8 @@ static int scst_xmit_response(struct scst_cmd *cmd)
* It shouldn't be because of the SCST_TGT_DEV_AFTER_*
* optimization.
*/
TRACE_DBG("Target driver %s xmit_response() needs thread "
"context, rescheduling", tgtt->name);
TRACE_MGMT_DBG("Target driver %s xmit_response() needs thread "
"context, rescheduling", tgtt->name);
res = SCST_CMD_STATE_RES_NEED_THREAD;
goto out;
}
@@ -3576,7 +3643,11 @@ void scst_tgt_cmd_done(struct scst_cmd *cmd,
cmd->cmd_hw_pending = 0;
if (unlikely(cmd->tgt_dev == NULL))
pref_context = SCST_CONTEXT_THREAD;
cmd->state = SCST_CMD_STATE_FINISHED;
scst_process_redirect_cmd(cmd, pref_context, 1);
TRACE_EXIT();
@@ -4120,8 +4191,8 @@ void scst_process_active_cmd(struct scst_cmd *cmd, bool atomic)
case SCST_CMD_STATE_PRE_DEV_DONE:
res = scst_pre_dev_done(cmd);
EXTRACHECKS_BUG_ON(res ==
SCST_CMD_STATE_RES_NEED_THREAD);
EXTRACHECKS_BUG_ON((res == SCST_CMD_STATE_RES_NEED_THREAD) &&
(cmd->state == SCST_CMD_STATE_PRE_DEV_DONE));
break;
case SCST_CMD_STATE_MODE_SELECT_CHECKS: