tracing: Rename stacktrace field to common_stacktrace
The histogram and synthetic events can use a pseudo event called
"stacktrace" that will create a stacktrace at the time of the event and
use it just like it was a normal field. We have other pseudo events such
as "common_cpu" and "common_timestamp". To stay consistent with that,
convert "stacktrace" to "common_stacktrace". As this was used in older
kernels, to keep backward compatibility, this will act just like
"common_cpu" did with "cpu". That is, "cpu" will be the same as
"common_cpu" unless the event has a "cpu" field. In which case, the
event's field is used. The same is true with "stacktrace".
Also update the documentation to reflect this change.
Link: https://lore.kernel.org/linux-trace-kernel/20230523230913.6860e28d@rorschach.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst
index 479c9ea..3c9b263 100644
--- a/Documentation/trace/histogram.rst
+++ b/Documentation/trace/histogram.rst
@@ -35,7 +35,7 @@
in place of an explicit value field - this is simply a count of
event hits. If 'values' isn't specified, an implicit 'hitcount'
value will be automatically created and used as the only value.
- Keys can be any field, or the special string 'stacktrace', which
+ Keys can be any field, or the special string 'common_stacktrace', which
will use the event's kernel stacktrace as the key. The keywords
'keys' or 'key' can be used to specify keys, and the keywords
'values', 'vals', or 'val' can be used to specify values. Compound
@@ -54,7 +54,7 @@
'compatible' if the fields named in the trigger share the same
number and type of fields and those fields also have the same names.
Note that any two events always share the compatible 'hitcount' and
- 'stacktrace' fields and can therefore be combined using those
+ 'common_stacktrace' fields and can therefore be combined using those
fields, however pointless that may be.
'hist' triggers add a 'hist' file to each event's subdirectory.
@@ -547,9 +547,9 @@
the hist trigger display symbolic call_sites, we can have the hist
trigger additionally display the complete set of kernel stack traces
that led to each call_site. To do that, we simply use the special
- value 'stacktrace' for the key parameter::
+ value 'common_stacktrace' for the key parameter::
- # echo 'hist:keys=stacktrace:values=bytes_req,bytes_alloc:sort=bytes_alloc' > \
+ # echo 'hist:keys=common_stacktrace:values=bytes_req,bytes_alloc:sort=bytes_alloc' > \
/sys/kernel/tracing/events/kmem/kmalloc/trigger
The above trigger will use the kernel stack trace in effect when an
@@ -561,9 +561,9 @@
every callpath to a kmalloc for a kernel compile)::
# cat /sys/kernel/tracing/events/kmem/kmalloc/hist
- # trigger info: hist:keys=stacktrace:vals=bytes_req,bytes_alloc:sort=bytes_alloc:size=2048 [active]
+ # trigger info: hist:keys=common_stacktrace:vals=bytes_req,bytes_alloc:sort=bytes_alloc:size=2048 [active]
- { stacktrace:
+ { common_stacktrace:
__kmalloc_track_caller+0x10b/0x1a0
kmemdup+0x20/0x50
hidraw_report_event+0x8a/0x120 [hid]
@@ -581,7 +581,7 @@
cpu_startup_entry+0x315/0x3e0
rest_init+0x7c/0x80
} hitcount: 3 bytes_req: 21 bytes_alloc: 24
- { stacktrace:
+ { common_stacktrace:
__kmalloc_track_caller+0x10b/0x1a0
kmemdup+0x20/0x50
hidraw_report_event+0x8a/0x120 [hid]
@@ -596,7 +596,7 @@
do_IRQ+0x5a/0xf0
ret_from_intr+0x0/0x30
} hitcount: 3 bytes_req: 21 bytes_alloc: 24
- { stacktrace:
+ { common_stacktrace:
kmem_cache_alloc_trace+0xeb/0x150
aa_alloc_task_context+0x27/0x40
apparmor_cred_prepare+0x1f/0x50
@@ -608,7 +608,7 @@
.
.
.
- { stacktrace:
+ { common_stacktrace:
__kmalloc+0x11b/0x1b0
i915_gem_execbuffer2+0x6c/0x2c0 [i915]
drm_ioctl+0x349/0x670 [drm]
@@ -616,7 +616,7 @@
SyS_ioctl+0x81/0xa0
system_call_fastpath+0x12/0x6a
} hitcount: 17726 bytes_req: 13944120 bytes_alloc: 19593808
- { stacktrace:
+ { common_stacktrace:
__kmalloc+0x11b/0x1b0
load_elf_phdrs+0x76/0xa0
load_elf_binary+0x102/0x1650
@@ -625,7 +625,7 @@
SyS_execve+0x3a/0x50
return_from_execve+0x0/0x23
} hitcount: 33348 bytes_req: 17152128 bytes_alloc: 20226048
- { stacktrace:
+ { common_stacktrace:
kmem_cache_alloc_trace+0xeb/0x150
apparmor_file_alloc_security+0x27/0x40
security_file_alloc+0x16/0x20
@@ -636,7 +636,7 @@
SyS_open+0x1e/0x20
system_call_fastpath+0x12/0x6a
} hitcount: 4766422 bytes_req: 9532844 bytes_alloc: 38131376
- { stacktrace:
+ { common_stacktrace:
__kmalloc+0x11b/0x1b0
seq_buf_alloc+0x1b/0x50
seq_read+0x2cc/0x370
@@ -1026,7 +1026,7 @@
First we set up an initially paused stacktrace trigger on the
netif_receive_skb event::
- # echo 'hist:key=stacktrace:vals=len:pause' > \
+ # echo 'hist:key=common_stacktrace:vals=len:pause' > \
/sys/kernel/tracing/events/net/netif_receive_skb/trigger
Next, we set up an 'enable_hist' trigger on the sched_process_exec
@@ -1060,9 +1060,9 @@
$ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz
# cat /sys/kernel/tracing/events/net/netif_receive_skb/hist
- # trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused]
+ # trigger info: hist:keys=common_stacktrace:vals=len:sort=hitcount:size=2048 [paused]
- { stacktrace:
+ { common_stacktrace:
__netif_receive_skb_core+0x46d/0x990
__netif_receive_skb+0x18/0x60
netif_receive_skb_internal+0x23/0x90
@@ -1079,7 +1079,7 @@
kthread+0xd2/0xf0
ret_from_fork+0x42/0x70
} hitcount: 85 len: 28884
- { stacktrace:
+ { common_stacktrace:
__netif_receive_skb_core+0x46d/0x990
__netif_receive_skb+0x18/0x60
netif_receive_skb_internal+0x23/0x90
@@ -1097,7 +1097,7 @@
irq_thread+0x11f/0x150
kthread+0xd2/0xf0
} hitcount: 98 len: 664329
- { stacktrace:
+ { common_stacktrace:
__netif_receive_skb_core+0x46d/0x990
__netif_receive_skb+0x18/0x60
process_backlog+0xa8/0x150
@@ -1115,7 +1115,7 @@
inet_sendmsg+0x64/0xa0
sock_sendmsg+0x3d/0x50
} hitcount: 115 len: 13030
- { stacktrace:
+ { common_stacktrace:
__netif_receive_skb_core+0x46d/0x990
__netif_receive_skb+0x18/0x60
netif_receive_skb_internal+0x23/0x90
@@ -1142,14 +1142,14 @@
into the histogram. In order to avoid having to set everything up
again, we can just clear the histogram first::
- # echo 'hist:key=stacktrace:vals=len:clear' >> \
+ # echo 'hist:key=common_stacktrace:vals=len:clear' >> \
/sys/kernel/tracing/events/net/netif_receive_skb/trigger
Just to verify that it is in fact cleared, here's what we now see in
the hist file::
# cat /sys/kernel/tracing/events/net/netif_receive_skb/hist
- # trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused]
+ # trigger info: hist:keys=common_stacktrace:vals=len:sort=hitcount:size=2048 [paused]
Totals:
Hits: 0
@@ -1485,12 +1485,12 @@
And here's an example that shows how to combine histogram data from
any two events even if they don't share any 'compatible' fields
- other than 'hitcount' and 'stacktrace'. These commands create a
+ other than 'hitcount' and 'common_stacktrace'. These commands create a
couple of triggers named 'bar' using those fields::
- # echo 'hist:name=bar:key=stacktrace:val=hitcount' > \
+ # echo 'hist:name=bar:key=common_stacktrace:val=hitcount' > \
/sys/kernel/tracing/events/sched/sched_process_fork/trigger
- # echo 'hist:name=bar:key=stacktrace:val=hitcount' > \
+ # echo 'hist:name=bar:key=common_stacktrace:val=hitcount' > \
/sys/kernel/tracing/events/net/netif_rx/trigger
And displaying the output of either shows some interesting if
@@ -1501,16 +1501,16 @@
# event histogram
#
- # trigger info: hist:name=bar:keys=stacktrace:vals=hitcount:sort=hitcount:size=2048 [active]
+ # trigger info: hist:name=bar:keys=common_stacktrace:vals=hitcount:sort=hitcount:size=2048 [active]
#
- { stacktrace:
+ { common_stacktrace:
kernel_clone+0x18e/0x330
kernel_thread+0x29/0x30
kthreadd+0x154/0x1b0
ret_from_fork+0x3f/0x70
} hitcount: 1
- { stacktrace:
+ { common_stacktrace:
netif_rx_internal+0xb2/0xd0
netif_rx_ni+0x20/0x70
dev_loopback_xmit+0xaa/0xd0
@@ -1528,7 +1528,7 @@
call_cpuidle+0x3b/0x60
cpu_startup_entry+0x22d/0x310
} hitcount: 1
- { stacktrace:
+ { common_stacktrace:
netif_rx_internal+0xb2/0xd0
netif_rx_ni+0x20/0x70
dev_loopback_xmit+0xaa/0xd0
@@ -1543,7 +1543,7 @@
SyS_sendto+0xe/0x10
entry_SYSCALL_64_fastpath+0x12/0x6a
} hitcount: 2
- { stacktrace:
+ { common_stacktrace:
netif_rx_internal+0xb2/0xd0
netif_rx+0x1c/0x60
loopback_xmit+0x6c/0xb0
@@ -1561,7 +1561,7 @@
sock_sendmsg+0x38/0x50
___sys_sendmsg+0x14e/0x270
} hitcount: 76
- { stacktrace:
+ { common_stacktrace:
netif_rx_internal+0xb2/0xd0
netif_rx+0x1c/0x60
loopback_xmit+0x6c/0xb0
@@ -1579,7 +1579,7 @@
sock_sendmsg+0x38/0x50
___sys_sendmsg+0x269/0x270
} hitcount: 77
- { stacktrace:
+ { common_stacktrace:
netif_rx_internal+0xb2/0xd0
netif_rx+0x1c/0x60
loopback_xmit+0x6c/0xb0
@@ -1597,7 +1597,7 @@
sock_sendmsg+0x38/0x50
SYSC_sendto+0xef/0x170
} hitcount: 88
- { stacktrace:
+ { common_stacktrace:
kernel_clone+0x18e/0x330
SyS_clone+0x19/0x20
entry_SYSCALL_64_fastpath+0x12/0x6a
@@ -1949,7 +1949,7 @@
# cd /sys/kernel/tracing
# echo 's:block_lat pid_t pid; u64 delta; unsigned long[] stack;' > dynamic_events
- # echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 2' >> events/sched/sched_switch/trigger
+ # echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=common_stacktrace if prev_state == 2' >> events/sched/sched_switch/trigger
# echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,s=$st:onmax($delta).trace(block_lat,prev_pid,$delta,$s)' >> events/sched/sched_switch/trigger
# echo 1 > events/synthetic/block_lat/enable
# cat trace
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 0e37322..7c4a0b7 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -806,6 +806,7 @@
FILTER_TRACE_FN,
FILTER_COMM,
FILTER_CPU,
+ FILTER_STACKTRACE,
};
extern int trace_event_raw_init(struct trace_event_call *call);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ebc5978..81801dc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5752,7 +5752,7 @@
"\t table using the key(s) and value(s) named, and the value of a\n"
"\t sum called 'hitcount' is incremented. Keys and values\n"
"\t correspond to fields in the event's format description. Keys\n"
- "\t can be any field, or the special string 'stacktrace'.\n"
+ "\t can be any field, or the special string 'common_stacktrace'.\n"
"\t Compound keys consisting of up to two fields can be specified\n"
"\t by the 'keys' keyword. Values must correspond to numeric\n"
"\t fields. Sort keys consisting of up to two fields can be\n"
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 654ffa4..57e539d 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -194,6 +194,8 @@
__generic_field(int, common_cpu, FILTER_CPU);
__generic_field(char *, COMM, FILTER_COMM);
__generic_field(char *, comm, FILTER_COMM);
+ __generic_field(char *, stacktrace, FILTER_STACKTRACE);
+ __generic_field(char *, STACKTRACE, FILTER_STACKTRACE);
return ret;
}
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 543cb7d..b97d3ad 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1364,7 +1364,7 @@
if (field->field)
field_name = field->field->name;
else
- field_name = "stacktrace";
+ field_name = "common_stacktrace";
} else if (field->flags & HIST_FIELD_FL_HITCOUNT)
field_name = "hitcount";
@@ -2367,7 +2367,7 @@
hist_data->enable_timestamps = true;
if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
hist_data->attrs->ts_in_usecs = true;
- } else if (strcmp(field_name, "stacktrace") == 0) {
+ } else if (strcmp(field_name, "common_stacktrace") == 0) {
*flags |= HIST_FIELD_FL_STACKTRACE;
} else if (strcmp(field_name, "common_cpu") == 0)
*flags |= HIST_FIELD_FL_CPU;
@@ -2378,11 +2378,15 @@
if (!field || !field->size) {
/*
* For backward compatibility, if field_name
- * was "cpu", then we treat this the same as
- * common_cpu. This also works for "CPU".
+ * was "cpu" or "stacktrace", then we treat this
+ * the same as common_cpu and common_stacktrace
+ * respectively. This also works for "CPU", and
+ * "STACKTRACE".
*/
if (field && field->filter_type == FILTER_CPU) {
*flags |= HIST_FIELD_FL_CPU;
+ } else if (field && field->filter_type == FILTER_STACKTRACE) {
+ *flags |= HIST_FIELD_FL_STACKTRACE;
} else {
hist_err(tr, HIST_ERR_FIELD_NOT_FOUND,
errpos(field_name));
@@ -5394,7 +5398,7 @@
if (key_field->field)
seq_printf(m, "%s.stacktrace", key_field->field->name);
else
- seq_puts(m, "stacktrace:\n");
+ seq_puts(m, "common_stacktrace:\n");
hist_trigger_stacktrace_print(m,
key + key_field->offset,
HIST_STACKTRACE_DEPTH);
@@ -5977,7 +5981,7 @@
if (field->field)
seq_printf(m, "%s.stacktrace", field->field->name);
else
- seq_puts(m, "stacktrace");
+ seq_puts(m, "common_stacktrace");
} else
hist_field_print(m, field);
}
