The symbol global_wb_domain is not GPL-exported to modules. In order
to allow kernel tracers implemented as GPL modules to access the
global writeback domain dirty limit, as used within the
global_dirty_state and balance_dirty_pages trace events, pass
a pointer to the global writeback domain as a new parameter for
those tracepoints.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: bpf@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
---
include/trace/events/writeback.h | 17 ++++++++++-------
mm/page-writeback.c | 9 +++++----
2 files changed, 15 insertions(+), 11 deletions(-)
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index d94def25e4dc..8fd774108c9c 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -531,11 +531,13 @@ TRACE_EVENT(writeback_queue_io,
TRACE_EVENT(global_dirty_state,
- TP_PROTO(unsigned long background_thresh,
+ TP_PROTO(struct wb_domain *domain,
+ unsigned long background_thresh,
unsigned long dirty_thresh
),
- TP_ARGS(background_thresh,
+ TP_ARGS(domain,
+ background_thresh,
dirty_thresh
),
@@ -558,7 +560,7 @@ TRACE_EVENT(global_dirty_state,
__entry->nr_written = global_node_page_state(NR_WRITTEN);
__entry->background_thresh = background_thresh;
__entry->dirty_thresh = dirty_thresh;
- __entry->dirty_limit = global_wb_domain.dirty_limit;
+ __entry->dirty_limit = domain->dirty_limit;
),
TP_printk("dirty=%lu writeback=%lu unstable=%lu "
@@ -625,7 +627,8 @@ TRACE_EVENT(bdi_dirty_ratelimit,
TRACE_EVENT(balance_dirty_pages,
- TP_PROTO(struct bdi_writeback *wb,
+ TP_PROTO(struct wb_domain *domain,
+ struct bdi_writeback *wb,
unsigned long thresh,
unsigned long bg_thresh,
unsigned long dirty,
@@ -638,7 +641,7 @@ TRACE_EVENT(balance_dirty_pages,
long pause,
unsigned long start_time),
- TP_ARGS(wb, thresh, bg_thresh, dirty, bdi_thresh, bdi_dirty,
+ TP_ARGS(domain, wb, thresh, bg_thresh, dirty, bdi_thresh, bdi_dirty,
dirty_ratelimit, task_ratelimit,
dirtied, period, pause, start_time),
@@ -664,8 +667,8 @@ TRACE_EVENT(balance_dirty_pages,
unsigned long freerun = (thresh + bg_thresh) / 2;
strscpy_pad(__entry->bdi, bdi_dev_name(wb->bdi), 32);
- __entry->limit = global_wb_domain.dirty_limit;
- __entry->setpoint = (global_wb_domain.dirty_limit +
+ __entry->limit = domain->dirty_limit;
+ __entry->setpoint = (domain->dirty_limit +
freerun) / 2;
__entry->dirty = dirty;
__entry->bdi_setpoint = __entry->setpoint *
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7326b54ab728..c76aae305360 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -443,9 +443,8 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc)
dtc->thresh = thresh;
dtc->bg_thresh = bg_thresh;
- /* we should eventually report the domain in the TP */
if (!gdtc)
- trace_global_dirty_state(bg_thresh, thresh);
+ trace_global_dirty_state(&global_wb_domain, bg_thresh, thresh);
}
/**
@@ -1736,7 +1735,8 @@ static void balance_dirty_pages(struct bdi_writeback *wb,
* do a reset, as it may be a light dirtier.
*/
if (pause < min_pause) {
- trace_balance_dirty_pages(wb,
+ trace_balance_dirty_pages(&global_wb_domain,
+ wb,
sdtc->thresh,
sdtc->bg_thresh,
sdtc->dirty,
@@ -1765,7 +1765,8 @@ static void balance_dirty_pages(struct bdi_writeback *wb,
}
pause:
- trace_balance_dirty_pages(wb,
+ trace_balance_dirty_pages(&global_wb_domain,
+ wb,
sdtc->thresh,
sdtc->bg_thresh,
sdtc->dirty,
--
2.17.1
