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Commit 3b1fff08 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent cfbcf468

arch/arm/kernel/perf_callchain.c

+1 −1
Original line number Diff line number Diff line
@@ -75,7 +75,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs 


	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);

}

arch/arm64/kernel/perf_callchain.c

+2 −2
Original line number Diff line number Diff line
@@ -122,7 +122,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, 


		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 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, 


		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

arch/metag/kernel/perf_callchain.c

+1 −1
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs 


	--frame;



	while ((entry->entry->nr < entry->max_stack) && frame)

	while ((entry->nr < entry->max_stack) && frame)

		frame = user_backtrace(frame, entry);

}

arch/mips/kernel/perf_event.c

+2 −2
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ static void save_raw_perf_callchain(struct perf_callchain_entry_ctx *entry, 
		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 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, 
	}

	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);

arch/powerpc/perf/callchain.c

+2 −2
Original line number Diff line number Diff line
@@ -247,7 +247,7 @@ static void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry, 
	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 @@ static void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry, 
	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;