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perf: Add context field to perf_event

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The perf_event overflow handler does not receive any caller-derived
argument, so many callers need to resort to looking up the perf_event
in their local data structure.  This is ugly and doesn't scale if a
single callback services many perf_events.

Fix by adding a context parameter to perf_event_create_kernel_counter()
(and derived hardware breakpoints APIs) and storing it in the perf_event.
The field can be accessed from the callback as event->overflow_handler_context.
All callers are updated.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1309362157-6596-2-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Avi Kivity 2011-06-29 18:42:35 +03:00 committed by Ingo Molnar
parent 89d6c0b5bd
commit 4dc0da8696
12 changed files with 44 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/arm/kernel/ptrace.c
View File

@ -479,7 +479,8 @@ static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
attr.bp_type = type;
attr.disabled = 1;
return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, tsk);
return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
tsk);
}
static int ptrace_gethbpregs(struct task_struct *tsk, long num,

2
arch/powerpc/kernel/ptrace.c
View File

@ -973,7 +973,7 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
&attr.bp_type);
thread->ptrace_bps[0] = bp = register_user_hw_breakpoint(&attr,
ptrace_triggered, task);
ptrace_triggered, NULL, task);
if (IS_ERR(bp)) {
thread->ptrace_bps[0] = NULL;
ptrace_put_breakpoints(task);

3
arch/sh/kernel/ptrace_32.c
View File

@ -91,7 +91,8 @@ static int set_single_step(struct task_struct *tsk, unsigned long addr)
attr.bp_len = HW_BREAKPOINT_LEN_2;
attr.bp_type = HW_BREAKPOINT_R;
bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk);
bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
NULL, tsk);
if (IS_ERR(bp))
return PTR_ERR(bp);

2
arch/x86/kernel/kgdb.c
View File

@ -638,7 +638,7 @@ void kgdb_arch_late(void)
for (i = 0; i < HBP_NUM; i++) {
if (breakinfo[i].pev)
continue;
breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL);
breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
if (IS_ERR((void * __force)breakinfo[i].pev)) {
printk(KERN_ERR "kgdb: Could not allocate hw"
"breakpoints\nDisabling the kernel debugger\n");

3
arch/x86/kernel/ptrace.c
View File

@ -715,7 +715,8 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
attr.bp_type = HW_BREAKPOINT_W;
attr.disabled = 1;
bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk);
bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
NULL, tsk);
/*
* CHECKME: the previous code returned -EIO if the addr wasn't

2
drivers/oprofile/oprofile_perf.c
View File

@ -79,7 +79,7 @@ static int op_create_counter(int cpu, int event)
pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
cpu, NULL,
op_overflow_handler);
op_overflow_handler, NULL);
if (IS_ERR(pevent))
return PTR_ERR(pevent);

10
include/linux/hw_breakpoint.h
View File

@ -73,6 +73,7 @@ static inline unsigned long hw_breakpoint_len(struct perf_event *bp)
extern struct perf_event *
register_user_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered,
void *context,
struct task_struct *tsk);
/* FIXME: only change from the attr, and don't unregister */
@ -85,11 +86,13 @@ modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr);
extern struct perf_event *
register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr,
perf_overflow_handler_t triggered,
void *context,
int cpu);
extern struct perf_event * __percpu *
register_wide_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered);
perf_overflow_handler_t triggered,
void *context);
extern int register_perf_hw_breakpoint(struct perf_event *bp);
extern int __register_perf_hw_breakpoint(struct perf_event *bp);
@ -115,6 +118,7 @@ static inline int __init init_hw_breakpoint(void) { return 0; }
static inline struct perf_event *
register_user_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered,
void *context,
struct task_struct *tsk) { return NULL; }
static inline int
modify_user_hw_breakpoint(struct perf_event *bp,
@ -122,10 +126,12 @@ modify_user_hw_breakpoint(struct perf_event *bp,
static inline struct perf_event *
register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr,
perf_overflow_handler_t triggered,
void *context,
int cpu) { return NULL; }
static inline struct perf_event * __percpu *
register_wide_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered) { return NULL; }
perf_overflow_handler_t triggered,
void *context) { return NULL; }
static inline int
register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; }
static inline int

4
include/linux/perf_event.h
View File

@ -839,6 +839,7 @@ struct perf_event {
u64 id;
perf_overflow_handler_t overflow_handler;
void *overflow_handler_context;
#ifdef CONFIG_EVENT_TRACING
struct ftrace_event_call *tp_event;
@ -960,7 +961,8 @@ extern struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr,
int cpu,
struct task_struct *task,
perf_overflow_handler_t callback);
perf_overflow_handler_t callback,
void *context);
extern u64 perf_event_read_value(struct perf_event *event,
u64 *enabled, u64 *running);

21
kernel/events/core.c
View File

@ -5745,7 +5745,8 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
struct task_struct *task,
struct perf_event *group_leader,
struct perf_event *parent_event,
perf_overflow_handler_t overflow_handler)
perf_overflow_handler_t overflow_handler,
void *context)
{
struct pmu *pmu;
struct perf_event *event;
@ -5803,10 +5804,13 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
#endif
}
if (!overflow_handler && parent_event)
if (!overflow_handler && parent_event) {
overflow_handler = parent_event->overflow_handler;
context = parent_event->overflow_handler_context;
}
event->overflow_handler = overflow_handler;
event->overflow_handler_context = context;
if (attr->disabled)
event->state = PERF_EVENT_STATE_OFF;
@ -6073,7 +6077,8 @@ SYSCALL_DEFINE5(perf_event_open,
}
}
event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL);
event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
NULL, NULL);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err_task;
@ -6258,7 +6263,8 @@ SYSCALL_DEFINE5(perf_event_open,
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
struct task_struct *task,
perf_overflow_handler_t overflow_handler)
perf_overflow_handler_t overflow_handler,
void *context)
{
struct perf_event_context *ctx;
struct perf_event *event;
@ -6268,7 +6274,8 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
* Get the target context (task or percpu):
*/
event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler);
event = perf_event_alloc(attr, cpu, task, NULL, NULL,
overflow_handler, context);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err;
@ -6552,7 +6559,7 @@ inherit_event(struct perf_event *parent_event,
parent_event->cpu,
child,
group_leader, parent_event,
NULL);
NULL, NULL);
if (IS_ERR(child_event))
return child_event;
get_ctx(child_ctx);
@ -6579,6 +6586,8 @@ inherit_event(struct perf_event *parent_event,
child_event->ctx = child_ctx;
child_event->overflow_handler = parent_event->overflow_handler;
child_event->overflow_handler_context
= parent_event->overflow_handler_context;
/*
* Precalculate sample_data sizes

10
kernel/events/hw_breakpoint.c
View File

@ -431,9 +431,11 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
struct perf_event *
register_user_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered,
void *context,
struct task_struct *tsk)
{
return perf_event_create_kernel_counter(attr, -1, tsk, triggered);
return perf_event_create_kernel_counter(attr, -1, tsk, triggered,
context);
}
EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
@ -502,7 +504,8 @@ EXPORT_SYMBOL_GPL(unregister_hw_breakpoint);
*/
struct perf_event * __percpu *
register_wide_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered)
perf_overflow_handler_t triggered,
void *context)
{
struct perf_event * __percpu *cpu_events, **pevent, *bp;
long err;
@ -515,7 +518,8 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr,
get_online_cpus();
for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(cpu_events, cpu);
bp = perf_event_create_kernel_counter(attr, cpu, NULL, triggered);
bp = perf_event_create_kernel_counter(attr, cpu, NULL,
triggered, context);
*pevent = bp;

2
kernel/watchdog.c
View File

@ -375,7 +375,7 @@ static int watchdog_nmi_enable(int cpu)
hw_nmi_watchdog_set_attr(wd_attr);
/* Try to register using hardware perf events */
event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback);
event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL);
if (!IS_ERR(event)) {
printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");
goto out_save;

2
samples/hw_breakpoint/data_breakpoint.c
View File

@ -60,7 +60,7 @@ static int __init hw_break_module_init(void)
attr.bp_len = HW_BREAKPOINT_LEN_4;
attr.bp_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R;
sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler);
sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler, NULL);
if (IS_ERR((void __force *)sample_hbp)) {
ret = PTR_ERR((void __force *)sample_hbp);
goto fail;