perf core: Add a 'nr' field to perf_event_callchain_context
We will use it to count how many addresses are in the entry->ip[] array,
excluding PERF_CONTEXT_{KERNEL,USER,etc} entries, so that we can really
return the number of entries specified by the user via the relevant
sysctl, kernel.perf_event_max_contexts, or via the per event
perf_event_attr.sample_max_stack knob.
This way we keep the perf_sample->ip_callchain->nr meaning, that is the
number of entries, be it real addresses or PERF_CONTEXT_ entries, while
honouring the max_stack knobs, i.e. the end result will be max_stack
entries if we have at least that many entries in a given stack trace.
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-s8teto51tdqvlfhefndtat9r@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/arch/arm/kernel/perf_callchain.c b/arch/arm/kernel/perf_callchain.c
index bc552e8..22bf1f6 100644
--- a/arch/arm/kernel/perf_callchain.c
+++ b/arch/arm/kernel/perf_callchain.c
@@ -75,7 +75,7 @@
tail = (struct frame_tail __user *)regs->ARM_fp - 1;
- while ((entry->entry->nr < entry->max_stack) &&
+ while ((entry->nr < entry->max_stack) &&
tail && !((unsigned long)tail & 0x3))
tail = user_backtrace(tail, entry);
}
diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c
index 0d60150..713ca82 100644
--- a/arch/arm64/kernel/perf_callchain.c
+++ b/arch/arm64/kernel/perf_callchain.c
@@ -122,7 +122,7 @@
tail = (struct frame_tail __user *)regs->regs[29];
- while (entry->entry->nr < entry->max_stack &&
+ while (entry->nr < entry->max_stack &&
tail && !((unsigned long)tail & 0xf))
tail = user_backtrace(tail, entry);
} else {
@@ -132,7 +132,7 @@
tail = (struct compat_frame_tail __user *)regs->compat_fp - 1;
- while ((entry->entry->nr < entry->max_stack) &&
+ while ((entry->nr < entry->max_stack) &&
tail && !((unsigned long)tail & 0x3))
tail = compat_user_backtrace(tail, entry);
#endif
diff --git a/arch/metag/kernel/perf_callchain.c b/arch/metag/kernel/perf_callchain.c
index b3261a9..3e8e048 100644
--- a/arch/metag/kernel/perf_callchain.c
+++ b/arch/metag/kernel/perf_callchain.c
@@ -65,7 +65,7 @@
--frame;
- while ((entry->entry->nr < entry->max_stack) && frame)
+ while ((entry->nr < entry->max_stack) && frame)
frame = user_backtrace(frame, entry);
}
diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 22395c7..d64056e 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -35,7 +35,7 @@
addr = *sp++;
if (__kernel_text_address(addr)) {
perf_callchain_store(entry, addr);
- if (entry->entry->nr >= entry->max_stack)
+ if (entry->nr >= entry->max_stack)
break;
}
}
@@ -59,7 +59,7 @@
}
do {
perf_callchain_store(entry, pc);
- if (entry->entry->nr >= entry->max_stack)
+ if (entry->nr >= entry->max_stack)
break;
pc = unwind_stack(current, &sp, pc, &ra);
} while (pc);
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index c9260c1..f68f213 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -247,7 +247,7 @@
sp = regs->gpr[1];
perf_callchain_store(entry, next_ip);
- while (entry->entry->nr < entry->max_stack) {
+ while (entry->nr < entry->max_stack) {
fp = (unsigned long __user *) sp;
if (!valid_user_sp(sp, 1) || read_user_stack_64(fp, &next_sp))
return;
@@ -453,7 +453,7 @@
sp = regs->gpr[1];
perf_callchain_store(entry, next_ip);
- while (entry->entry->nr < entry->max_stack) {
+ while (entry->nr < entry->max_stack) {
fp = (unsigned int __user *) (unsigned long) sp;
if (!valid_user_sp(sp, 0) || read_user_stack_32(fp, &next_sp))
return;
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index bcc5376..710f327 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1756,7 +1756,7 @@
}
}
#endif
- } while (entry->entry->nr < entry->max_stack);
+ } while (entry->nr < entry->max_stack);
}
static inline int
@@ -1790,7 +1790,7 @@
pc = sf.callers_pc;
ufp = (unsigned long)sf.fp + STACK_BIAS;
perf_callchain_store(entry, pc);
- } while (entry->entry->nr < entry->max_stack);
+ } while (entry->nr < entry->max_stack);
}
static void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,
@@ -1822,7 +1822,7 @@
ufp = (unsigned long)sf.fp;
}
perf_callchain_store(entry, pc);
- } while (entry->entry->nr < entry->max_stack);
+ } while (entry->nr < entry->max_stack);
}
void
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 07f2b01..5de96a1 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2283,7 +2283,7 @@
fp = compat_ptr(ss_base + regs->bp);
pagefault_disable();
- while (entry->entry->nr < entry->max_stack) {
+ while (entry->nr < entry->max_stack) {
unsigned long bytes;
frame.next_frame = 0;
frame.return_address = 0;
@@ -2343,7 +2343,7 @@
return;
pagefault_disable();
- while (entry->entry->nr < entry->max_stack) {
+ while (entry->nr < entry->max_stack) {
unsigned long bytes;
frame.next_frame = NULL;
frame.return_address = 0;
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index dbd1824..3803bb1 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -64,6 +64,7 @@
struct perf_callchain_entry_ctx {
struct perf_callchain_entry *entry;
u32 max_stack;
+ u32 nr;
};
struct perf_raw_record {
@@ -1080,9 +1081,10 @@
static inline int perf_callchain_store(struct perf_callchain_entry_ctx *ctx, u64 ip)
{
- struct perf_callchain_entry *entry = ctx->entry;
- if (entry->nr < ctx->max_stack) {
+ if (ctx->nr < ctx->max_stack) {
+ struct perf_callchain_entry *entry = ctx->entry;
entry->ip[entry->nr++] = ip;
+ ++ctx->nr;
return 0;
} else {
return -1; /* no more room, stop walking the stack */
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index af95ad9..8774ff8 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -196,8 +196,7 @@
ctx.entry = entry;
ctx.max_stack = max_stack;
-
- entry->nr = init_nr;
+ ctx.nr = entry->nr = init_nr;
if (kernel && !user_mode(regs)) {
if (add_mark)