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perf: split perf_trace_buf_prepare into alloc and update parts 

split allows to move expensive update of 'struct trace_entry' to later phase.
Repurpose unused 1st argument of perf_tp_event() to indicate event type.

While splitting use temp variable 'rctx' instead of '*rctx' to avoid
unnecessary loads done by the compiler due to -fno-strict-aliasing

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Alexei Starovoitov 2016-04-06 18:43:24 -07:00 committed by David S. Miller
parent e93735be6a
commit 1e1dcd93b4
8 changed files with 49 additions and 42 deletions
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2
include/linux/perf_event.h
View File

@ -1016,7 +1016,7 @@ static inline bool perf_paranoid_kernel(void)
}
extern void perf_event_init(void);
extern void perf_tp_event(u64 addr, u64 count, void *record,
extern void perf_tp_event(u16 event_type, u64 count, void *record,
int entry_size, struct pt_regs *regs,
struct hlist_head *head, int rctx,
struct task_struct *task);

8
include/linux/trace_events.h
View File

@ -605,15 +605,15 @@ extern void perf_trace_del(struct perf_event *event, int flags);
extern int ftrace_profile_set_filter(struct perf_event *event, int event_id,
char *filter_str);
extern void ftrace_profile_free_filter(struct perf_event *event);
extern void *perf_trace_buf_prepare(int size, unsigned short type,
struct pt_regs **regs, int *rctxp);
void perf_trace_buf_update(void *record, u16 type);
void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp);
static inline void
perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,
perf_trace_buf_submit(void *raw_data, int size, int rctx, u16 type,
u64 count, struct pt_regs *regs, void *head,
struct task_struct *task)
{
perf_tp_event(addr, count, raw_data, size, regs, head, rctx, task);
perf_tp_event(type, count, raw_data, size, regs, head, rctx, task);
}
#endif

8
include/trace/perf.h
View File

@ -53,8 +53,7 @@ perf_trace_##call(void *__data, proto) \
sizeof(u64)); \
__entry_size -= sizeof(u32); \
\
entry = perf_trace_buf_prepare(__entry_size, \
event_call->event.type, &__regs, &rctx); \
entry = perf_trace_buf_alloc(__entry_size, &__regs, &rctx); \
if (!entry) \
return; \
\
@ -64,8 +63,9 @@ perf_trace_##call(void *__data, proto) \
\
{ assign; } \
\
perf_trace_buf_submit(entry, __entry_size, rctx, 0, \
__count, __regs, head, __task); \
perf_trace_buf_submit(entry, __entry_size, rctx, \
event_call->event.type, __count, __regs, \
head, __task); \
}
/*

6
kernel/events/core.c
View File

@ -6987,7 +6987,7 @@ static int perf_tp_event_match(struct perf_event *event,
return 1;
}
void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
struct pt_regs *regs, struct hlist_head *head, int rctx,
struct task_struct *task)
{
@ -6999,9 +6999,11 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
.data = record,
};
perf_sample_data_init(&data, addr, 0);
perf_sample_data_init(&data, 0, 0);
data.raw = &raw;
perf_trace_buf_update(record, event_type);
hlist_for_each_entry_rcu(event, head, hlist_entry) {
if (perf_tp_event_match(event, &data, regs))
perf_swevent_event(event, count, &data, regs);

39
kernel/trace/trace_event_perf.c
View File

@ -260,42 +260,43 @@ void perf_trace_del(struct perf_event *p_event, int flags)
tp_event->class->reg(tp_event, TRACE_REG_PERF_DEL, p_event);
}
void *perf_trace_buf_prepare(int size, unsigned short type,
struct pt_regs **regs, int *rctxp)
void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp)
{
struct trace_entry *entry;
unsigned long flags;
char *raw_data;
int pc;
int rctx;
BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
"perf buffer not large enough"))
"perf buffer not large enough"))
return NULL;
pc = preempt_count();
*rctxp = perf_swevent_get_recursion_context();
if (*rctxp < 0)
*rctxp = rctx = perf_swevent_get_recursion_context();
if (rctx < 0)
return NULL;
if (regs)
*regs = this_cpu_ptr(&__perf_regs[*rctxp]);
raw_data = this_cpu_ptr(perf_trace_buf[*rctxp]);
*regs = this_cpu_ptr(&__perf_regs[rctx]);
raw_data = this_cpu_ptr(perf_trace_buf[rctx]);
/* zero the dead bytes from align to not leak stack to user */
memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
return raw_data;
}
EXPORT_SYMBOL_GPL(perf_trace_buf_alloc);
NOKPROBE_SYMBOL(perf_trace_buf_alloc);
void perf_trace_buf_update(void *record, u16 type)
{
struct trace_entry *entry = record;
int pc = preempt_count();
unsigned long flags;
entry = (struct trace_entry *)raw_data;
local_save_flags(flags);
tracing_generic_entry_update(entry, flags, pc);
entry->type = type;
return raw_data;
}
EXPORT_SYMBOL_GPL(perf_trace_buf_prepare);
NOKPROBE_SYMBOL(perf_trace_buf_prepare);
NOKPROBE_SYMBOL(perf_trace_buf_update);
#ifdef CONFIG_FUNCTION_TRACER
static void
@ -319,13 +320,13 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip,
memset(&regs, 0, sizeof(regs));
perf_fetch_caller_regs(&regs);
entry = perf_trace_buf_prepare(ENTRY_SIZE, TRACE_FN, NULL, &rctx);
entry = perf_trace_buf_alloc(ENTRY_SIZE, NULL, &rctx);
if (!entry)
return;
entry->ip = ip;
entry->parent_ip = parent_ip;
perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, 0,
perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN,
1, &regs, head, NULL);
#undef ENTRY_SIZE

10
kernel/trace/trace_kprobe.c
View File

@ -1149,14 +1149,15 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
entry = perf_trace_buf_alloc(size, NULL, &rctx);
if (!entry)
return;
entry->ip = (unsigned long)tk->rp.kp.addr;
memset(&entry[1], 0, dsize);
store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
head, NULL);
}
NOKPROBE_SYMBOL(kprobe_perf_func);
@ -1184,14 +1185,15 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
entry = perf_trace_buf_alloc(size, NULL, &rctx);
if (!entry)
return;
entry->func = (unsigned long)tk->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
head, NULL);
}
NOKPROBE_SYMBOL(kretprobe_perf_func);
#endif /* CONFIG_PERF_EVENTS */

13
kernel/trace/trace_syscalls.c
View File

@ -587,15 +587,16 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
size = ALIGN(size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
sys_data->enter_event->event.type, NULL, &rctx);
rec = perf_trace_buf_alloc(size, NULL, &rctx);
if (!rec)
return;
rec->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args,
(unsigned long *)&rec->args);
perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
perf_trace_buf_submit(rec, size, rctx,
sys_data->enter_event->event.type, 1, regs,
head, NULL);
}
static int perf_sysenter_enable(struct trace_event_call *call)
@ -660,14 +661,14 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
sys_data->exit_event->event.type, NULL, &rctx);
rec = perf_trace_buf_alloc(size, NULL, &rctx);
if (!rec)
return;
rec->nr = syscall_nr;
rec->ret = syscall_get_return_value(current, regs);
perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
1, regs, head, NULL);
}
static int perf_sysexit_enable(struct trace_event_call *call)

5
kernel/trace/trace_uprobe.c
View File

@ -1131,7 +1131,7 @@ static void __uprobe_perf_func(struct trace_uprobe *tu,
if (hlist_empty(head))
goto out;
entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
entry = perf_trace_buf_alloc(size, NULL, &rctx);
if (!entry)
goto out;
@ -1152,7 +1152,8 @@ static void __uprobe_perf_func(struct trace_uprobe *tu,
memset(data + len, 0, size - esize - len);
}
perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
head, NULL);
out:
preempt_enable();
}