diff options
Diffstat (limited to 'Documentation/trace/kprobetrace.txt')
| -rw-r--r-- | Documentation/trace/kprobetrace.txt | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index e4991fb1eedc..1a3a3d6bc2a8 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -8,11 +8,12 @@ Overview -------- These events are similar to tracepoint based events. Instead of Tracepoint, this is based on kprobes (kprobe and kretprobe). So it can probe wherever -kprobes can probe (this means, all functions body except for __kprobes -functions). Unlike the Tracepoint based event, this can be added and removed +kprobes can probe (this means, all functions except those with +__kprobes/nokprobe_inline annotation and those marked NOKPROBE_SYMBOL). +Unlike the Tracepoint based event, this can be added and removed dynamically, on the fly. -To enable this feature, build your kernel with CONFIG_KPROBE_EVENT=y. +To enable this feature, build your kernel with CONFIG_KPROBE_EVENTS=y. Similar to the events tracer, this doesn't need to be activated via current_tracer. Instead of that, add probe points via @@ -23,7 +24,7 @@ current_tracer. Instead of that, add probe points via Synopsis of kprobe_events ------------------------- p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS] : Set a probe - r[:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS] : Set a return probe + r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS] : Set a return probe -:[GRP/]EVENT : Clear a probe GRP : Group name. If omitted, use "kprobes" for it. @@ -32,6 +33,9 @@ Synopsis of kprobe_events MOD : Module name which has given SYM. SYM[+offs] : Symbol+offset where the probe is inserted. MEMADDR : Address where the probe is inserted. + MAXACTIVE : Maximum number of instances of the specified function that + can be probed simultaneously, or 0 for the default value + as defined in Documentation/kprobes.txt section 1.3.1. FETCHARGS : Arguments. Each probe can have up to 128 args. %REG : Fetch register REG |