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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Frederic Weisbecker <frederic@kernel.org>,
Joel Fernandes <joel@joelfernandes.org>,
Andy Lutomirski <luto@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
"Frank Ch. Eigler" <fche@redhat.com>
Subject: [PATCH 01/16 v3] function_graph: Convert ret_stack to a series of longs
Date: Fri, 24 May 2019 23:16:34 -0400 [thread overview]
Message-ID: <20190525031745.235716308@goodmis.org> (raw)
In-Reply-To: 20190525031633.811342628@goodmis.org
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
In order to make it possible to have multiple callbacks registered with the
function_graph tracer, the retstack needs to be converted from an array of
ftrace_ret_stack structures to an array of longs. This will allow to store
the list of callbacks on the stack for the return side of the functions.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
include/linux/sched.h | 2 +-
kernel/trace/fgraph.c | 124 ++++++++++++++++++++++++------------------
2 files changed, 71 insertions(+), 55 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 11837410690f..1850d8a3c3f0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1113,7 +1113,7 @@ struct task_struct {
int curr_ret_depth;
/* Stack of return addresses for return function tracing: */
- struct ftrace_ret_stack *ret_stack;
+ unsigned long *ret_stack;
/* Timestamp for last schedule: */
unsigned long long ftrace_timestamp;
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 8dfd5021b933..df48bbfc0a5a 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -23,6 +23,18 @@
#define ASSIGN_OPS_HASH(opsname, val)
#endif
+#define FGRAPH_RET_SIZE sizeof(struct ftrace_ret_stack)
+#define FGRAPH_RET_INDEX (ALIGN(FGRAPH_RET_SIZE, sizeof(long)) / sizeof(long))
+#define SHADOW_STACK_SIZE (PAGE_SIZE)
+#define SHADOW_STACK_INDEX \
+ (ALIGN(SHADOW_STACK_SIZE, sizeof(long)) / sizeof(long))
+/* Leave on a buffer at the end */
+#define SHADOW_STACK_MAX_INDEX (SHADOW_STACK_INDEX - FGRAPH_RET_INDEX)
+
+#define RET_STACK(t, index) ((struct ftrace_ret_stack *)(&(t)->ret_stack[index]))
+#define RET_STACK_INC(c) ({ c += FGRAPH_RET_INDEX; })
+#define RET_STACK_DEC(c) ({ c -= FGRAPH_RET_INDEX; })
+
static bool kill_ftrace_graph;
int ftrace_graph_active;
@@ -59,6 +71,7 @@ static int
ftrace_push_return_trace(unsigned long ret, unsigned long func,
unsigned long frame_pointer, unsigned long *retp)
{
+ struct ftrace_ret_stack *ret_stack;
unsigned long long calltime;
int index;
@@ -75,23 +88,25 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func,
smp_rmb();
/* The return trace stack is full */
- if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+ if (current->curr_ret_stack >= SHADOW_STACK_MAX_INDEX) {
atomic_inc(¤t->trace_overrun);
return -EBUSY;
}
calltime = trace_clock_local();
- index = ++current->curr_ret_stack;
+ index = current->curr_ret_stack;
+ RET_STACK_INC(current->curr_ret_stack);
+ ret_stack = RET_STACK(current, index);
barrier();
- current->ret_stack[index].ret = ret;
- current->ret_stack[index].func = func;
- current->ret_stack[index].calltime = calltime;
+ ret_stack->ret = ret;
+ ret_stack->func = func;
+ ret_stack->calltime = calltime;
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
- current->ret_stack[index].fp = frame_pointer;
+ ret_stack->fp = frame_pointer;
#endif
#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
- current->ret_stack[index].retp = retp;
+ ret_stack->retp = retp;
#endif
return 0;
}
@@ -113,7 +128,7 @@ int function_graph_enter(unsigned long ret, unsigned long func,
return 0;
out_ret:
- current->curr_ret_stack--;
+ RET_STACK_DEC(current->curr_ret_stack);
out:
current->curr_ret_depth--;
return -EBUSY;
@@ -124,11 +139,13 @@ static void
ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
unsigned long frame_pointer)
{
+ struct ftrace_ret_stack *ret_stack;
int index;
index = current->curr_ret_stack;
+ RET_STACK_DEC(index);
- if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
+ if (unlikely(index < 0 || index > SHADOW_STACK_MAX_INDEX)) {
ftrace_graph_stop();
WARN_ON(1);
/* Might as well panic, otherwise we have no where to go */
@@ -136,6 +153,7 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
return;
}
+ ret_stack = RET_STACK(current, index);
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
/*
* The arch may choose to record the frame pointer used
@@ -151,22 +169,22 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
* Note, -mfentry does not use frame pointers, and this test
* is not needed if CC_USING_FENTRY is set.
*/
- if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+ if (unlikely(ret_stack->fp != frame_pointer)) {
ftrace_graph_stop();
WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
" from func %ps return to %lx\n",
current->ret_stack[index].fp,
frame_pointer,
- (void *)current->ret_stack[index].func,
- current->ret_stack[index].ret);
+ (void *)ret_stack->func,
+ ret_stack->ret);
*ret = (unsigned long)panic;
return;
}
#endif
- *ret = current->ret_stack[index].ret;
- trace->func = current->ret_stack[index].func;
- trace->calltime = current->ret_stack[index].calltime;
+ *ret = ret_stack->ret;
+ trace->func = ret_stack->func;
+ trace->calltime = ret_stack->calltime;
trace->overrun = atomic_read(¤t->trace_overrun);
trace->depth = current->curr_ret_depth--;
/*
@@ -220,7 +238,7 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
* curr_ret_stack is after that.
*/
barrier();
- current->curr_ret_stack--;
+ RET_STACK_DEC(current->curr_ret_stack);
if (unlikely(!ret)) {
ftrace_graph_stop();
@@ -246,12 +264,13 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
struct ftrace_ret_stack *
ftrace_graph_get_ret_stack(struct task_struct *task, int idx)
{
- idx = task->curr_ret_stack - idx;
+ int index = task->curr_ret_stack;
- if (idx >= 0 && idx <= task->curr_ret_stack)
- return &task->ret_stack[idx];
+ index -= FGRAPH_RET_INDEX * (idx + 1);
+ if (index < 0)
+ return NULL;
- return NULL;
+ return RET_STACK(task, index);
}
/**
@@ -273,18 +292,20 @@ ftrace_graph_get_ret_stack(struct task_struct *task, int idx)
unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
unsigned long ret, unsigned long *retp)
{
+ struct ftrace_ret_stack *ret_stack;
int index = task->curr_ret_stack;
int i;
if (ret != (unsigned long)return_to_handler)
return ret;
- if (index < 0)
- return ret;
+ RET_STACK_DEC(index);
- for (i = 0; i <= index; i++)
- if (task->ret_stack[i].retp == retp)
- return task->ret_stack[i].ret;
+ for (i = index; i >= 0; RET_STACK_DEC(i)) {
+ ret_stack = RET_STACK(task, i);
+ if (ret_stack->retp == retp)
+ return ret_stack->ret;
+ }
return ret;
}
@@ -298,14 +319,15 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
return ret;
task_idx = task->curr_ret_stack;
+ RET_STACK_DEC(task_idx);
if (!task->ret_stack || task_idx < *idx)
return ret;
task_idx -= *idx;
- (*idx)++;
+ RET_STACK_INC(*idx);
- return task->ret_stack[task_idx].ret;
+ return RET_STACK(task, task_idx);
}
#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
@@ -339,7 +361,7 @@ trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
-static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
+static int alloc_retstack_tasklist(unsigned long **ret_stack_list)
{
int i;
int ret = 0;
@@ -347,10 +369,7 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
struct task_struct *g, *t;
for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
- ret_stack_list[i] =
- kmalloc_array(FTRACE_RETFUNC_DEPTH,
- sizeof(struct ftrace_ret_stack),
- GFP_KERNEL);
+ ret_stack_list[i] = kmalloc(SHADOW_STACK_SIZE, GFP_KERNEL);
if (!ret_stack_list[i]) {
start = 0;
end = i;
@@ -369,9 +388,9 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
if (t->ret_stack == NULL) {
atomic_set(&t->tracing_graph_pause, 0);
atomic_set(&t->trace_overrun, 0);
- t->curr_ret_stack = -1;
+ t->curr_ret_stack = 0;
t->curr_ret_depth = -1;
- /* Make sure the tasks see the -1 first: */
+ /* Make sure the tasks see the 0 first: */
smp_wmb();
t->ret_stack = ret_stack_list[start++];
}
@@ -389,6 +408,7 @@ static void
ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
struct task_struct *prev, struct task_struct *next)
{
+ struct ftrace_ret_stack *ret_stack;
unsigned long long timestamp;
int index;
@@ -413,8 +433,11 @@ ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
*/
timestamp -= next->ftrace_timestamp;
- for (index = next->curr_ret_stack; index >= 0; index--)
- next->ret_stack[index].calltime += timestamp;
+ for (index = next->curr_ret_stack - FGRAPH_RET_INDEX; index >= 0; ) {
+ ret_stack = RET_STACK(next, index);
+ ret_stack->calltime += timestamp;
+ index -= FGRAPH_RET_INDEX;
+ }
}
static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
@@ -457,10 +480,10 @@ void update_function_graph_func(void)
ftrace_graph_entry = __ftrace_graph_entry;
}
-static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
+static DEFINE_PER_CPU(unsigned long *, idle_ret_stack);
static void
-graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
+graph_init_task(struct task_struct *t, unsigned long *ret_stack)
{
atomic_set(&t->tracing_graph_pause, 0);
atomic_set(&t->trace_overrun, 0);
@@ -476,7 +499,7 @@ graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
*/
void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
{
- t->curr_ret_stack = -1;
+ t->curr_ret_stack = 0;
t->curr_ret_depth = -1;
/*
* The idle task has no parent, it either has its own
@@ -486,14 +509,11 @@ void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
if (ftrace_graph_active) {
- struct ftrace_ret_stack *ret_stack;
+ unsigned long *ret_stack;
ret_stack = per_cpu(idle_ret_stack, cpu);
if (!ret_stack) {
- ret_stack =
- kmalloc_array(FTRACE_RETFUNC_DEPTH,
- sizeof(struct ftrace_ret_stack),
- GFP_KERNEL);
+ ret_stack = kmalloc(SHADOW_STACK_SIZE, GFP_KERNEL);
if (!ret_stack)
return;
per_cpu(idle_ret_stack, cpu) = ret_stack;
@@ -507,15 +527,13 @@ void ftrace_graph_init_task(struct task_struct *t)
{
/* Make sure we do not use the parent ret_stack */
t->ret_stack = NULL;
- t->curr_ret_stack = -1;
+ t->curr_ret_stack = 0;
t->curr_ret_depth = -1;
if (ftrace_graph_active) {
- struct ftrace_ret_stack *ret_stack;
+ unsigned long *ret_stack;
- ret_stack = kmalloc_array(FTRACE_RETFUNC_DEPTH,
- sizeof(struct ftrace_ret_stack),
- GFP_KERNEL);
+ ret_stack = kmalloc(SHADOW_STACK_SIZE, GFP_KERNEL);
if (!ret_stack)
return;
graph_init_task(t, ret_stack);
@@ -524,7 +542,7 @@ void ftrace_graph_init_task(struct task_struct *t)
void ftrace_graph_exit_task(struct task_struct *t)
{
- struct ftrace_ret_stack *ret_stack = t->ret_stack;
+ unsigned long *ret_stack = t->ret_stack;
t->ret_stack = NULL;
/* NULL must become visible to IRQs before we free it: */
@@ -536,12 +554,10 @@ void ftrace_graph_exit_task(struct task_struct *t)
/* Allocate a return stack for each task */
static int start_graph_tracing(void)
{
- struct ftrace_ret_stack **ret_stack_list;
+ unsigned long **ret_stack_list;
int ret, cpu;
- ret_stack_list = kmalloc_array(FTRACE_RETSTACK_ALLOC_SIZE,
- sizeof(struct ftrace_ret_stack *),
- GFP_KERNEL);
+ ret_stack_list = kmalloc(SHADOW_STACK_SIZE, GFP_KERNEL);
if (!ret_stack_list)
return -ENOMEM;
--
2.20.1
next prev parent reply other threads:[~2019-05-25 3:17 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-25 3:16 [PATCH 00/16 v3] function_graph: Rewrite to allow multiple users Steven Rostedt
2019-05-25 3:16 ` Steven Rostedt [this message]
2019-05-28 9:50 ` [PATCH 01/16 v3] function_graph: Convert ret_stack to a series of longs Joel Fernandes
2019-05-28 12:58 ` Steven Rostedt
2019-05-28 17:46 ` Joel Fernandes
2019-05-25 3:16 ` [PATCH 02/16 v3] fgraph: Use BUILD_BUG_ON() to make sure we have structures divisible by long Steven Rostedt
2019-05-25 3:16 ` [PATCH 03/16 v3] fgraph: Have the current->ret_stack go down not up Steven Rostedt
2019-05-25 3:16 ` [PATCH 04/16 v3] function_graph: Add an array structure that will allow multiple callbacks Steven Rostedt
2019-05-25 3:16 ` [PATCH 05/16 v3] function_graph: Allow multiple users to attach to function graph Steven Rostedt
2019-05-25 3:16 ` [PATCH 06/16 v3] function_graph: Remove logic around ftrace_graph_entry and return Steven Rostedt
2019-05-25 3:16 ` [PATCH 07/16 v3] ftrace/function_graph: Pass fgraph_ops to function graph callbacks Steven Rostedt
2019-05-25 3:16 ` [PATCH 08/16 v3] ftrace: Allow function_graph tracer to be enabled in instances Steven Rostedt
2019-05-25 3:16 ` [PATCH 09/16 v3] ftrace: Allow ftrace startup flags exist without dynamic ftrace Steven Rostedt
2019-05-25 3:16 ` [PATCH 10/16 v3] function_graph: Have the instances use their own ftrace_ops for filtering Steven Rostedt
2019-05-25 3:16 ` [PATCH 11/16 v3] function_graph: Add "task variables" per task for fgraph_ops Steven Rostedt
2019-05-25 3:16 ` [PATCH 12/16 v3] function_graph: Move set_graph_function tests to shadow stack global var Steven Rostedt
2019-05-25 3:16 ` [PATCH 13/16 v3] function_graph: Move graph depth stored data " Steven Rostedt
2019-05-25 3:16 ` [PATCH 14/16 v3] function_graph: Move graph notrace bit " Steven Rostedt
2019-05-25 3:16 ` [PATCH 15/16 v3] function_graph: Implement fgraph_reserve_data() and fgraph_retrieve_data() Steven Rostedt
2019-05-25 3:16 ` [PATCH 16/16 v3] function_graph: Add selftest for passing local variables Steven Rostedt
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