From ee6dd0db4d8de41a0a0bc37d8d87a0b1623f83b0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 25 Apr 2019 11:45:16 +0200 Subject: [PATCH] tracing: Simplify stack trace retrieval Replace the indirection through struct stack_trace by using the storage array based interfaces. Signed-off-by: Thomas Gleixner Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Alexander Potapenko Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: linux-mm@kvack.org Cc: David Rientjes Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport Cc: Akinobu Mita Cc: Christoph Hellwig Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy Cc: Marek Szyprowski Cc: Johannes Thumshirn Cc: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon Cc: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen Cc: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org Cc: David Airlie Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tom Zanussi Cc: Miroslav Benes Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094803.248604594@linutronix.de --- kernel/trace/trace.c | 40 +++++++++++++--------------------------- 1 file changed, 13 insertions(+), 27 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d8369d27c1af..0ce8515dd470 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2774,22 +2774,18 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, { struct trace_event_call *call = &event_kernel_stack; struct ring_buffer_event *event; + unsigned int size, nr_entries; struct ftrace_stack *fstack; struct stack_entry *entry; - struct stack_trace trace; - int size = FTRACE_KSTACK_ENTRIES; int stackidx; - trace.nr_entries = 0; - trace.skip = skip; - /* * Add one, for this function and the call to save_stack_trace() * If regs is set, then these functions will not be in the way. */ #ifndef CONFIG_UNWINDER_ORC if (!regs) - trace.skip++; + skip++; #endif /* @@ -2816,28 +2812,24 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, barrier(); fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx; - trace.entries = fstack->calls; - trace.max_entries = FTRACE_KSTACK_ENTRIES; + size = ARRAY_SIZE(fstack->calls); - if (regs) - save_stack_trace_regs(regs, &trace); - else - save_stack_trace(&trace); - - if (trace.nr_entries > size) - size = trace.nr_entries; - - size *= sizeof(unsigned long); + if (regs) { + nr_entries = stack_trace_save_regs(regs, fstack->calls, + size, skip); + } else { + nr_entries = stack_trace_save(fstack->calls, size, skip); + } + size = nr_entries * sizeof(unsigned long); event = __trace_buffer_lock_reserve(buffer, TRACE_STACK, sizeof(*entry) + size, flags, pc); if (!event) goto out; entry = ring_buffer_event_data(event); - memcpy(&entry->caller, trace.entries, size); - - entry->size = trace.nr_entries; + memcpy(&entry->caller, fstack->calls, size); + entry->size = nr_entries; if (!call_filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event); @@ -2916,7 +2908,6 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) struct trace_event_call *call = &event_user_stack; struct ring_buffer_event *event; struct userstack_entry *entry; - struct stack_trace trace; if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE)) return; @@ -2947,12 +2938,7 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) entry->tgid = current->tgid; memset(&entry->caller, 0, sizeof(entry->caller)); - trace.nr_entries = 0; - trace.max_entries = FTRACE_STACK_ENTRIES; - trace.skip = 0; - trace.entries = entry->caller; - - save_stack_trace_user(&trace); + stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES); if (!call_filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event);