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Kirill Smelkov
linux
Commits
bba8d3d1
Commit
bba8d3d1
authored
Feb 02, 2023
by
Paul E. McKenney
Browse files
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Browse Files
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Plain Diff
Merge branch 'stall.2023.01.09a' into HEAD
stall.2023.01.09a: RCU CPU stall-warning updates.
parents
8e1704b6
84ec7c20
Changes
9
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9 changed files
with
112 additions
and
5 deletions
+112
-5
Documentation/admin-guide/kernel-parameters.txt
Documentation/admin-guide/kernel-parameters.txt
+6
-0
include/linux/kernel_stat.h
include/linux/kernel_stat.h
+13
-1
kernel/rcu/Kconfig.debug
kernel/rcu/Kconfig.debug
+14
-1
kernel/rcu/rcu.h
kernel/rcu/rcu.h
+1
-0
kernel/rcu/tree.c
kernel/rcu/tree.c
+18
-0
kernel/rcu/tree.h
kernel/rcu/tree.h
+19
-0
kernel/rcu/tree_stall.h
kernel/rcu/tree_stall.h
+34
-3
kernel/rcu/update.c
kernel/rcu/update.c
+2
-0
kernel/sched/core.c
kernel/sched/core.c
+5
-0
No files found.
Documentation/admin-guide/kernel-parameters.txt
View file @
bba8d3d1
...
...
@@ -5113,6 +5113,12 @@
rcupdate.rcu_cpu_stall_timeout to be used (after
conversion from seconds to milliseconds).
rcupdate.rcu_cpu_stall_cputime= [KNL]
Provide statistics on the cputime and count of
interrupts and tasks during the sampling period. For
multiple continuous RCU stalls, all sampling periods
begin at half of the first RCU stall timeout.
rcupdate.rcu_exp_stall_task_details= [KNL]
Print stack dumps of any tasks blocking the
current expedited RCU grace period during an
...
...
include/linux/kernel_stat.h
View file @
bba8d3d1
...
...
@@ -52,6 +52,7 @@ DECLARE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
#define kstat_cpu(cpu) per_cpu(kstat, cpu)
#define kcpustat_cpu(cpu) per_cpu(kernel_cpustat, cpu)
extern
unsigned
long
long
nr_context_switches_cpu
(
int
cpu
);
extern
unsigned
long
long
nr_context_switches
(
void
);
extern
unsigned
int
kstat_irqs_cpu
(
unsigned
int
irq
,
int
cpu
);
...
...
@@ -67,6 +68,17 @@ static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
return
kstat_cpu
(
cpu
).
softirqs
[
irq
];
}
static
inline
unsigned
int
kstat_cpu_softirqs_sum
(
int
cpu
)
{
int
i
;
unsigned
int
sum
=
0
;
for
(
i
=
0
;
i
<
NR_SOFTIRQS
;
i
++
)
sum
+=
kstat_softirqs_cpu
(
i
,
cpu
);
return
sum
;
}
/*
* Number of interrupts per specific IRQ source, since bootup
*/
...
...
@@ -75,7 +87,7 @@ extern unsigned int kstat_irqs_usr(unsigned int irq);
/*
* Number of interrupts per cpu, since bootup
*/
static
inline
unsigned
int
kstat_cpu_irqs_sum
(
unsigned
int
cpu
)
static
inline
unsigned
long
kstat_cpu_irqs_sum
(
unsigned
int
cpu
)
{
return
kstat_cpu
(
cpu
).
irqs_sum
;
}
...
...
kernel/rcu/Kconfig.debug
View file @
bba8d3d1
...
...
@@ -82,7 +82,7 @@ config RCU_CPU_STALL_TIMEOUT
config RCU_EXP_CPU_STALL_TIMEOUT
int "Expedited RCU CPU stall timeout in milliseconds"
depends on RCU_STALL_COMMON
range 0
21
000
range 0
300
000
default 0
help
If a given expedited RCU grace period extends more than the
...
...
@@ -92,6 +92,19 @@ config RCU_EXP_CPU_STALL_TIMEOUT
says to use the RCU_CPU_STALL_TIMEOUT value converted from
seconds to milliseconds.
config RCU_CPU_STALL_CPUTIME
bool "Provide additional RCU stall debug information"
depends on RCU_STALL_COMMON
default n
help
Collect statistics during the sampling period, such as the number of
(hard interrupts, soft interrupts, task switches) and the cputime of
(hard interrupts, soft interrupts, kernel tasks) are added to the
RCU stall report. For multiple continuous RCU stalls, all sampling
periods begin at half of the first RCU stall timeout.
The boot option rcupdate.rcu_cpu_stall_cputime has the same function
as this one, but will override this if it exists.
config RCU_TRACE
bool "Enable tracing for RCU"
depends on DEBUG_KERNEL
...
...
kernel/rcu/rcu.h
View file @
bba8d3d1
...
...
@@ -224,6 +224,7 @@ extern int rcu_cpu_stall_ftrace_dump;
extern
int
rcu_cpu_stall_suppress
;
extern
int
rcu_cpu_stall_timeout
;
extern
int
rcu_exp_cpu_stall_timeout
;
extern
int
rcu_cpu_stall_cputime
;
extern
bool
rcu_exp_stall_task_details
__read_mostly
;
int
rcu_jiffies_till_stall_check
(
void
);
int
rcu_exp_jiffies_till_stall_check
(
void
);
...
...
kernel/rcu/tree.c
View file @
bba8d3d1
...
...
@@ -866,6 +866,24 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
rdp
->
rcu_iw_gp_seq
=
rnp
->
gp_seq
;
irq_work_queue_on
(
&
rdp
->
rcu_iw
,
rdp
->
cpu
);
}
if
(
rcu_cpu_stall_cputime
&&
rdp
->
snap_record
.
gp_seq
!=
rdp
->
gp_seq
)
{
int
cpu
=
rdp
->
cpu
;
struct
rcu_snap_record
*
rsrp
;
struct
kernel_cpustat
*
kcsp
;
kcsp
=
&
kcpustat_cpu
(
cpu
);
rsrp
=
&
rdp
->
snap_record
;
rsrp
->
cputime_irq
=
kcpustat_field
(
kcsp
,
CPUTIME_IRQ
,
cpu
);
rsrp
->
cputime_softirq
=
kcpustat_field
(
kcsp
,
CPUTIME_SOFTIRQ
,
cpu
);
rsrp
->
cputime_system
=
kcpustat_field
(
kcsp
,
CPUTIME_SYSTEM
,
cpu
);
rsrp
->
nr_hardirqs
=
kstat_cpu_irqs_sum
(
rdp
->
cpu
);
rsrp
->
nr_softirqs
=
kstat_cpu_softirqs_sum
(
rdp
->
cpu
);
rsrp
->
nr_csw
=
nr_context_switches_cpu
(
rdp
->
cpu
);
rsrp
->
jiffies
=
jiffies
;
rsrp
->
gp_seq
=
rdp
->
gp_seq
;
}
}
return
0
;
...
...
kernel/rcu/tree.h
View file @
bba8d3d1
...
...
@@ -158,6 +158,23 @@ union rcu_noqs {
u16
s
;
/* Set of bits, aggregate OR here. */
};
/*
* Record the snapshot of the core stats at half of the first RCU stall timeout.
* The member gp_seq is used to ensure that all members are updated only once
* during the sampling period. The snapshot is taken only if this gp_seq is not
* equal to rdp->gp_seq.
*/
struct
rcu_snap_record
{
unsigned
long
gp_seq
;
/* Track rdp->gp_seq counter */
u64
cputime_irq
;
/* Accumulated cputime of hard irqs */
u64
cputime_softirq
;
/* Accumulated cputime of soft irqs */
u64
cputime_system
;
/* Accumulated cputime of kernel tasks */
unsigned
long
nr_hardirqs
;
/* Accumulated number of hard irqs */
unsigned
int
nr_softirqs
;
/* Accumulated number of soft irqs */
unsigned
long
long
nr_csw
;
/* Accumulated number of task switches */
unsigned
long
jiffies
;
/* Track jiffies value */
};
/* Per-CPU data for read-copy update. */
struct
rcu_data
{
/* 1) quiescent-state and grace-period handling : */
...
...
@@ -262,6 +279,8 @@ struct rcu_data {
short
rcu_onl_gp_flags
;
/* ->gp_flags at last online. */
unsigned
long
last_fqs_resched
;
/* Time of last rcu_resched(). */
unsigned
long
last_sched_clock
;
/* Jiffies of last rcu_sched_clock_irq(). */
struct
rcu_snap_record
snap_record
;
/* Snapshot of core stats at half of */
/* the first RCU stall timeout */
long
lazy_len
;
/* Length of buffered lazy callbacks. */
int
cpu
;
...
...
kernel/rcu/tree_stall.h
View file @
bba8d3d1
...
...
@@ -39,7 +39,7 @@ int rcu_exp_jiffies_till_stall_check(void)
// CONFIG_RCU_EXP_CPU_STALL_TIMEOUT, so check the allowed range.
// The minimum clamped value is "2UL", because at least one full
// tick has to be guaranteed.
till_stall_check
=
clamp
(
msecs_to_jiffies
(
cpu_stall_timeout
),
2UL
,
21
UL
*
HZ
);
till_stall_check
=
clamp
(
msecs_to_jiffies
(
cpu_stall_timeout
),
2UL
,
300
UL
*
HZ
);
if
(
cpu_stall_timeout
&&
jiffies_to_msecs
(
till_stall_check
)
!=
cpu_stall_timeout
)
WRITE_ONCE
(
rcu_exp_cpu_stall_timeout
,
jiffies_to_msecs
(
till_stall_check
));
...
...
@@ -428,6 +428,35 @@ static bool rcu_is_rcuc_kthread_starving(struct rcu_data *rdp, unsigned long *jp
return
j
>
2
*
HZ
;
}
static
void
print_cpu_stat_info
(
int
cpu
)
{
struct
rcu_snap_record
rsr
,
*
rsrp
;
struct
rcu_data
*
rdp
=
per_cpu_ptr
(
&
rcu_data
,
cpu
);
struct
kernel_cpustat
*
kcsp
=
&
kcpustat_cpu
(
cpu
);
if
(
!
rcu_cpu_stall_cputime
)
return
;
rsrp
=
&
rdp
->
snap_record
;
if
(
rsrp
->
gp_seq
!=
rdp
->
gp_seq
)
return
;
rsr
.
cputime_irq
=
kcpustat_field
(
kcsp
,
CPUTIME_IRQ
,
cpu
);
rsr
.
cputime_softirq
=
kcpustat_field
(
kcsp
,
CPUTIME_SOFTIRQ
,
cpu
);
rsr
.
cputime_system
=
kcpustat_field
(
kcsp
,
CPUTIME_SYSTEM
,
cpu
);
pr_err
(
"
\t
hardirqs softirqs csw/system
\n
"
);
pr_err
(
"
\t
number: %8ld %10d %12lld
\n
"
,
kstat_cpu_irqs_sum
(
cpu
)
-
rsrp
->
nr_hardirqs
,
kstat_cpu_softirqs_sum
(
cpu
)
-
rsrp
->
nr_softirqs
,
nr_context_switches_cpu
(
cpu
)
-
rsrp
->
nr_csw
);
pr_err
(
"
\t
cputime: %8lld %10lld %12lld ==> %d(ms)
\n
"
,
div_u64
(
rsr
.
cputime_irq
-
rsrp
->
cputime_irq
,
NSEC_PER_MSEC
),
div_u64
(
rsr
.
cputime_softirq
-
rsrp
->
cputime_softirq
,
NSEC_PER_MSEC
),
div_u64
(
rsr
.
cputime_system
-
rsrp
->
cputime_system
,
NSEC_PER_MSEC
),
jiffies_to_msecs
(
jiffies
-
rsrp
->
jiffies
));
}
/*
* Print out diagnostic information for the specified stalled CPU.
*
...
...
@@ -484,6 +513,8 @@ static void print_cpu_stall_info(int cpu)
data_race
(
rcu_state
.
n_force_qs
)
-
rcu_state
.
n_force_qs_gpstart
,
rcuc_starved
?
buf
:
""
,
falsepositive
?
" (false positive?)"
:
""
);
print_cpu_stat_info
(
cpu
);
}
/* Complain about starvation of grace-period kthread. */
...
...
@@ -588,7 +619,7 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
for_each_possible_cpu
(
cpu
)
totqlen
+=
rcu_get_n_cbs_cpu
(
cpu
);
pr_
cont
(
"
\t
(detected by %d, t=%ld jiffies, g=%ld, q=%lu ncpus=%d)
\n
"
,
pr_
err
(
"
\t
(detected by %d, t=%ld jiffies, g=%ld, q=%lu ncpus=%d)
\n
"
,
smp_processor_id
(),
(
long
)(
jiffies
-
gps
),
(
long
)
rcu_seq_current
(
&
rcu_state
.
gp_seq
),
totqlen
,
rcu_state
.
n_online_cpus
);
if
(
ndetected
)
{
...
...
@@ -649,7 +680,7 @@ static void print_cpu_stall(unsigned long gps)
raw_spin_unlock_irqrestore_rcu_node
(
rdp
->
mynode
,
flags
);
for_each_possible_cpu
(
cpu
)
totqlen
+=
rcu_get_n_cbs_cpu
(
cpu
);
pr_
cont
(
"
\t
(t=%lu jiffies g=%ld q=%lu ncpus=%d)
\n
"
,
pr_
err
(
"
\t
(t=%lu jiffies g=%ld q=%lu ncpus=%d)
\n
"
,
jiffies
-
gps
,
(
long
)
rcu_seq_current
(
&
rcu_state
.
gp_seq
),
totqlen
,
rcu_state
.
n_online_cpus
);
...
...
kernel/rcu/update.c
View file @
bba8d3d1
...
...
@@ -547,6 +547,8 @@ int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
module_param
(
rcu_cpu_stall_timeout
,
int
,
0644
);
int
rcu_exp_cpu_stall_timeout
__read_mostly
=
CONFIG_RCU_EXP_CPU_STALL_TIMEOUT
;
module_param
(
rcu_exp_cpu_stall_timeout
,
int
,
0644
);
int
rcu_cpu_stall_cputime
__read_mostly
=
IS_ENABLED
(
CONFIG_RCU_CPU_STALL_CPUTIME
);
module_param
(
rcu_cpu_stall_cputime
,
int
,
0644
);
bool
rcu_exp_stall_task_details
__read_mostly
;
module_param
(
rcu_exp_stall_task_details
,
bool
,
0644
);
#endif
/* #ifdef CONFIG_RCU_STALL_COMMON */
...
...
kernel/sched/core.c
View file @
bba8d3d1
...
...
@@ -5282,6 +5282,11 @@ bool single_task_running(void)
}
EXPORT_SYMBOL
(
single_task_running
);
unsigned
long
long
nr_context_switches_cpu
(
int
cpu
)
{
return
cpu_rq
(
cpu
)
->
nr_switches
;
}
unsigned
long
long
nr_context_switches
(
void
)
{
int
i
;
...
...
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