Re: [PATCH 5/7] uprobes/perf: Teach trace_uprobe/perf code to pre-filter
* Oleg Nesterov [2013-02-04 20:02:58]:
> Finally implement uprobe_perf_filter() which checks ->nr_systemwide or
> ->perf_events to figure out whether we need to insert the breakpoint.
>
> uprobe_perf_open/close are changed to do uprobe_apply(true/false) when
> the new perf event comes or goes away.
>
> Note that currently this is very suboptimal:
>
> - uprobe_register() called by TRACE_REG_PERF_REGISTER becomes a
> heavy nop, consumer->filter() always returns F at this stage.
>
> As it was already discussed we need uprobe_register_only() to
> avoid the costly register_for_each_vma() when possible.
>
> - uprobe_apply() is oftenly overkill. Unless "nr_systemwide != 0"
> changes we need uprobe_apply_mm(), unapply_uprobe() is almost
> what we need.
>
> - uprobe_apply() can be simply avoided sometimes, see the next
> changes.
>
> Testing:
>
> # perf probe -x /lib/libc.so.6 syscall
>
> # perl -e 'syscall -1 while 1' &
> [1] 530
>
> # perf record -e probe_libc:syscall perl -e 'syscall -1 for 1..10;
> sleep 1'
>
> # perf report --show-total-period
> 100.00%10 perl libc-2.8.so[.] syscall
>
> Before this patch:
>
> # cat /sys/kernel/debug/tracing/uprobe_profile
> /lib/libc.so.6 syscall 79291
>
> A huge ->nrhit == 79291 reflects the fact that the background process
> 530 constantly hits this breakpoint too, even if doesn't contribute to
> the output.
>
> After the patch:
>
> # cat /sys/kernel/debug/tracing/uprobe_profile
> /lib/libc.so.6 syscall 10
>
> This shows that only the target process was punished by int3.
>
> Signed-off-by: Oleg Nesterov
Acked-by: Srikar Dronamraju
> ---
> kernel/trace/trace_uprobe.c | 46 --
> 1 files changed, 43 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index f05ec32..5d5a261 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -554,7 +554,12 @@ static inline bool is_trace_uprobe_enabled(struct
> trace_uprobe *tu)
> return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE);
> }
>
> -static int probe_event_enable(struct trace_uprobe *tu, int flag)
> +typedef bool (*filter_func_t)(struct uprobe_consumer *self,
> + enum uprobe_filter_ctx ctx,
> + struct mm_struct *mm);
> +
> +static int
> +probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
> {
> int ret = 0;
>
> @@ -564,6 +569,7 @@ static int probe_event_enable(struct trace_uprobe *tu,
> int flag)
> WARN_ON(!uprobe_filter_is_empty(>filter));
>
> tu->flags |= flag;
> + tu->consumer.filter = filter;
> ret = uprobe_register(tu->inode, tu->offset, >consumer);
> if (ret)
> tu->flags &= ~flag;
> @@ -653,6 +659,22 @@ static int set_print_fmt(struct trace_uprobe *tu)
> }
>
> #ifdef CONFIG_PERF_EVENTS
> +static bool
> +__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct
> *mm)
> +{
> + struct perf_event *event;
> +
> + if (filter->nr_systemwide)
> + return true;
> +
> + list_for_each_entry(event, >perf_events, hw.tp_list) {
> + if (event->hw.tp_target->mm == mm)
> + return true;
> + }
> +
> + return false;
> +}
> +
> static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event
> *event)
> {
> write_lock(>filter.rwlock);
> @@ -662,6 +684,8 @@ static int uprobe_perf_open(struct trace_uprobe *tu,
> struct perf_event *event)
> tu->filter.nr_systemwide++;
> write_unlock(>filter.rwlock);
>
> + uprobe_apply(tu->inode, tu->offset, >consumer, true);
> +
> return 0;
> }
>
> @@ -674,9 +698,25 @@ static int uprobe_perf_close(struct trace_uprobe *tu,
> struct perf_event *event)
> tu->filter.nr_systemwide--;
> write_unlock(>filter.rwlock);
>
> + uprobe_apply(tu->inode, tu->offset, >consumer, false);
> +
> return 0;
> }
>
> +static bool uprobe_perf_filter(struct uprobe_consumer *uc,
> + enum uprobe_filter_ctx ctx, struct mm_struct
> *mm)
> +{
> + struct trace_uprobe *tu;
> + int ret;
> +
> + tu = container_of(uc, struct trace_uprobe, consumer);
> + read_lock(>filter.rwlock);
> + ret = __uprobe_perf_filter(>filter, mm);
> + read_unlock(>filter.rwlock);
> +
> + return ret;
> +}
> +
> /* uprobe profile handler */
> static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
> {
> @@ -719,7 +759,7 @@ int trace_uprobe_register(struct ftrace_event_call
> *event, enum trace_reg type,
>
> switch (type) {
> case TRACE_REG_REGISTER:
> - return probe_event_enable(tu, TP_FLAG_TRACE);
> +
Re: [PATCH 5/7] uprobes/perf: Teach trace_uprobe/perf code to pre-filter
* Oleg Nesterov o...@redhat.com [2013-02-04 20:02:58]:
Finally implement uprobe_perf_filter() which checks -nr_systemwide or
-perf_events to figure out whether we need to insert the breakpoint.
uprobe_perf_open/close are changed to do uprobe_apply(true/false) when
the new perf event comes or goes away.
Note that currently this is very suboptimal:
- uprobe_register() called by TRACE_REG_PERF_REGISTER becomes a
heavy nop, consumer-filter() always returns F at this stage.
As it was already discussed we need uprobe_register_only() to
avoid the costly register_for_each_vma() when possible.
- uprobe_apply() is oftenly overkill. Unless nr_systemwide != 0
changes we need uprobe_apply_mm(), unapply_uprobe() is almost
what we need.
- uprobe_apply() can be simply avoided sometimes, see the next
changes.
Testing:
# perf probe -x /lib/libc.so.6 syscall
# perl -e 'syscall -1 while 1'
[1] 530
# perf record -e probe_libc:syscall perl -e 'syscall -1 for 1..10;
sleep 1'
# perf report --show-total-period
100.00%10 perl libc-2.8.so[.] syscall
Before this patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 79291
A huge -nrhit == 79291 reflects the fact that the background process
530 constantly hits this breakpoint too, even if doesn't contribute to
the output.
After the patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 10
This shows that only the target process was punished by int3.
Signed-off-by: Oleg Nesterov o...@redhat.com
Acked-by: Srikar Dronamraju sri...@linux.vnet.ibm.com
---
kernel/trace/trace_uprobe.c | 46 --
1 files changed, 43 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index f05ec32..5d5a261 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -554,7 +554,12 @@ static inline bool is_trace_uprobe_enabled(struct
trace_uprobe *tu)
return tu-flags (TP_FLAG_TRACE | TP_FLAG_PROFILE);
}
-static int probe_event_enable(struct trace_uprobe *tu, int flag)
+typedef bool (*filter_func_t)(struct uprobe_consumer *self,
+ enum uprobe_filter_ctx ctx,
+ struct mm_struct *mm);
+
+static int
+probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
{
int ret = 0;
@@ -564,6 +569,7 @@ static int probe_event_enable(struct trace_uprobe *tu,
int flag)
WARN_ON(!uprobe_filter_is_empty(tu-filter));
tu-flags |= flag;
+ tu-consumer.filter = filter;
ret = uprobe_register(tu-inode, tu-offset, tu-consumer);
if (ret)
tu-flags = ~flag;
@@ -653,6 +659,22 @@ static int set_print_fmt(struct trace_uprobe *tu)
}
#ifdef CONFIG_PERF_EVENTS
+static bool
+__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct
*mm)
+{
+ struct perf_event *event;
+
+ if (filter-nr_systemwide)
+ return true;
+
+ list_for_each_entry(event, filter-perf_events, hw.tp_list) {
+ if (event-hw.tp_target-mm == mm)
+ return true;
+ }
+
+ return false;
+}
+
static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event
*event)
{
write_lock(tu-filter.rwlock);
@@ -662,6 +684,8 @@ static int uprobe_perf_open(struct trace_uprobe *tu,
struct perf_event *event)
tu-filter.nr_systemwide++;
write_unlock(tu-filter.rwlock);
+ uprobe_apply(tu-inode, tu-offset, tu-consumer, true);
+
return 0;
}
@@ -674,9 +698,25 @@ static int uprobe_perf_close(struct trace_uprobe *tu,
struct perf_event *event)
tu-filter.nr_systemwide--;
write_unlock(tu-filter.rwlock);
+ uprobe_apply(tu-inode, tu-offset, tu-consumer, false);
+
return 0;
}
+static bool uprobe_perf_filter(struct uprobe_consumer *uc,
+ enum uprobe_filter_ctx ctx, struct mm_struct
*mm)
+{
+ struct trace_uprobe *tu;
+ int ret;
+
+ tu = container_of(uc, struct trace_uprobe, consumer);
+ read_lock(tu-filter.rwlock);
+ ret = __uprobe_perf_filter(tu-filter, mm);
+ read_unlock(tu-filter.rwlock);
+
+ return ret;
+}
+
/* uprobe profile handler */
static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
{
@@ -719,7 +759,7 @@ int trace_uprobe_register(struct ftrace_event_call
*event, enum trace_reg type,
switch (type) {
case TRACE_REG_REGISTER:
- return probe_event_enable(tu, TP_FLAG_TRACE);
+ return probe_event_enable(tu, TP_FLAG_TRACE, NULL);
case TRACE_REG_UNREGISTER:
[PATCH 5/7] uprobes/perf: Teach trace_uprobe/perf code to pre-filter
Finally implement uprobe_perf_filter() which checks ->nr_systemwide or
->perf_events to figure out whether we need to insert the breakpoint.
uprobe_perf_open/close are changed to do uprobe_apply(true/false) when
the new perf event comes or goes away.
Note that currently this is very suboptimal:
- uprobe_register() called by TRACE_REG_PERF_REGISTER becomes a
heavy nop, consumer->filter() always returns F at this stage.
As it was already discussed we need uprobe_register_only() to
avoid the costly register_for_each_vma() when possible.
- uprobe_apply() is oftenly overkill. Unless "nr_systemwide != 0"
changes we need uprobe_apply_mm(), unapply_uprobe() is almost
what we need.
- uprobe_apply() can be simply avoided sometimes, see the next
changes.
Testing:
# perf probe -x /lib/libc.so.6 syscall
# perl -e 'syscall -1 while 1' &
[1] 530
# perf record -e probe_libc:syscall perl -e 'syscall -1 for 1..10;
sleep 1'
# perf report --show-total-period
100.00%10 perl libc-2.8.so[.] syscall
Before this patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 79291
A huge ->nrhit == 79291 reflects the fact that the background process
530 constantly hits this breakpoint too, even if doesn't contribute to
the output.
After the patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 10
This shows that only the target process was punished by int3.
Signed-off-by: Oleg Nesterov
---
kernel/trace/trace_uprobe.c | 46 --
1 files changed, 43 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index f05ec32..5d5a261 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -554,7 +554,12 @@ static inline bool is_trace_uprobe_enabled(struct
trace_uprobe *tu)
return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE);
}
-static int probe_event_enable(struct trace_uprobe *tu, int flag)
+typedef bool (*filter_func_t)(struct uprobe_consumer *self,
+ enum uprobe_filter_ctx ctx,
+ struct mm_struct *mm);
+
+static int
+probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
{
int ret = 0;
@@ -564,6 +569,7 @@ static int probe_event_enable(struct trace_uprobe *tu, int
flag)
WARN_ON(!uprobe_filter_is_empty(>filter));
tu->flags |= flag;
+ tu->consumer.filter = filter;
ret = uprobe_register(tu->inode, tu->offset, >consumer);
if (ret)
tu->flags &= ~flag;
@@ -653,6 +659,22 @@ static int set_print_fmt(struct trace_uprobe *tu)
}
#ifdef CONFIG_PERF_EVENTS
+static bool
+__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
+{
+ struct perf_event *event;
+
+ if (filter->nr_systemwide)
+ return true;
+
+ list_for_each_entry(event, >perf_events, hw.tp_list) {
+ if (event->hw.tp_target->mm == mm)
+ return true;
+ }
+
+ return false;
+}
+
static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
{
write_lock(>filter.rwlock);
@@ -662,6 +684,8 @@ static int uprobe_perf_open(struct trace_uprobe *tu, struct
perf_event *event)
tu->filter.nr_systemwide++;
write_unlock(>filter.rwlock);
+ uprobe_apply(tu->inode, tu->offset, >consumer, true);
+
return 0;
}
@@ -674,9 +698,25 @@ static int uprobe_perf_close(struct trace_uprobe *tu,
struct perf_event *event)
tu->filter.nr_systemwide--;
write_unlock(>filter.rwlock);
+ uprobe_apply(tu->inode, tu->offset, >consumer, false);
+
return 0;
}
+static bool uprobe_perf_filter(struct uprobe_consumer *uc,
+ enum uprobe_filter_ctx ctx, struct mm_struct
*mm)
+{
+ struct trace_uprobe *tu;
+ int ret;
+
+ tu = container_of(uc, struct trace_uprobe, consumer);
+ read_lock(>filter.rwlock);
+ ret = __uprobe_perf_filter(>filter, mm);
+ read_unlock(>filter.rwlock);
+
+ return ret;
+}
+
/* uprobe profile handler */
static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
{
@@ -719,7 +759,7 @@ int trace_uprobe_register(struct ftrace_event_call *event,
enum trace_reg type,
switch (type) {
case TRACE_REG_REGISTER:
- return probe_event_enable(tu, TP_FLAG_TRACE);
+ return probe_event_enable(tu, TP_FLAG_TRACE, NULL);
case TRACE_REG_UNREGISTER:
probe_event_disable(tu, TP_FLAG_TRACE);
@@ -727,7 +767,7 @@ int trace_uprobe_register(struct ftrace_event_call *event,
enum trace_reg type,
[PATCH 5/7] uprobes/perf: Teach trace_uprobe/perf code to pre-filter
Finally implement uprobe_perf_filter() which checks -nr_systemwide or
-perf_events to figure out whether we need to insert the breakpoint.
uprobe_perf_open/close are changed to do uprobe_apply(true/false) when
the new perf event comes or goes away.
Note that currently this is very suboptimal:
- uprobe_register() called by TRACE_REG_PERF_REGISTER becomes a
heavy nop, consumer-filter() always returns F at this stage.
As it was already discussed we need uprobe_register_only() to
avoid the costly register_for_each_vma() when possible.
- uprobe_apply() is oftenly overkill. Unless nr_systemwide != 0
changes we need uprobe_apply_mm(), unapply_uprobe() is almost
what we need.
- uprobe_apply() can be simply avoided sometimes, see the next
changes.
Testing:
# perf probe -x /lib/libc.so.6 syscall
# perl -e 'syscall -1 while 1'
[1] 530
# perf record -e probe_libc:syscall perl -e 'syscall -1 for 1..10;
sleep 1'
# perf report --show-total-period
100.00%10 perl libc-2.8.so[.] syscall
Before this patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 79291
A huge -nrhit == 79291 reflects the fact that the background process
530 constantly hits this breakpoint too, even if doesn't contribute to
the output.
After the patch:
# cat /sys/kernel/debug/tracing/uprobe_profile
/lib/libc.so.6 syscall 10
This shows that only the target process was punished by int3.
Signed-off-by: Oleg Nesterov o...@redhat.com
---
kernel/trace/trace_uprobe.c | 46 --
1 files changed, 43 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index f05ec32..5d5a261 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -554,7 +554,12 @@ static inline bool is_trace_uprobe_enabled(struct
trace_uprobe *tu)
return tu-flags (TP_FLAG_TRACE | TP_FLAG_PROFILE);
}
-static int probe_event_enable(struct trace_uprobe *tu, int flag)
+typedef bool (*filter_func_t)(struct uprobe_consumer *self,
+ enum uprobe_filter_ctx ctx,
+ struct mm_struct *mm);
+
+static int
+probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
{
int ret = 0;
@@ -564,6 +569,7 @@ static int probe_event_enable(struct trace_uprobe *tu, int
flag)
WARN_ON(!uprobe_filter_is_empty(tu-filter));
tu-flags |= flag;
+ tu-consumer.filter = filter;
ret = uprobe_register(tu-inode, tu-offset, tu-consumer);
if (ret)
tu-flags = ~flag;
@@ -653,6 +659,22 @@ static int set_print_fmt(struct trace_uprobe *tu)
}
#ifdef CONFIG_PERF_EVENTS
+static bool
+__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
+{
+ struct perf_event *event;
+
+ if (filter-nr_systemwide)
+ return true;
+
+ list_for_each_entry(event, filter-perf_events, hw.tp_list) {
+ if (event-hw.tp_target-mm == mm)
+ return true;
+ }
+
+ return false;
+}
+
static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
{
write_lock(tu-filter.rwlock);
@@ -662,6 +684,8 @@ static int uprobe_perf_open(struct trace_uprobe *tu, struct
perf_event *event)
tu-filter.nr_systemwide++;
write_unlock(tu-filter.rwlock);
+ uprobe_apply(tu-inode, tu-offset, tu-consumer, true);
+
return 0;
}
@@ -674,9 +698,25 @@ static int uprobe_perf_close(struct trace_uprobe *tu,
struct perf_event *event)
tu-filter.nr_systemwide--;
write_unlock(tu-filter.rwlock);
+ uprobe_apply(tu-inode, tu-offset, tu-consumer, false);
+
return 0;
}
+static bool uprobe_perf_filter(struct uprobe_consumer *uc,
+ enum uprobe_filter_ctx ctx, struct mm_struct
*mm)
+{
+ struct trace_uprobe *tu;
+ int ret;
+
+ tu = container_of(uc, struct trace_uprobe, consumer);
+ read_lock(tu-filter.rwlock);
+ ret = __uprobe_perf_filter(tu-filter, mm);
+ read_unlock(tu-filter.rwlock);
+
+ return ret;
+}
+
/* uprobe profile handler */
static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
{
@@ -719,7 +759,7 @@ int trace_uprobe_register(struct ftrace_event_call *event,
enum trace_reg type,
switch (type) {
case TRACE_REG_REGISTER:
- return probe_event_enable(tu, TP_FLAG_TRACE);
+ return probe_event_enable(tu, TP_FLAG_TRACE, NULL);
case TRACE_REG_UNREGISTER:
probe_event_disable(tu, TP_FLAG_TRACE);
@@ -727,7 +767,7 @@ int trace_uprobe_register(struct ftrace_event_call *event,
enum
