[It seems beneficial to queue this simple trace event for
next/upstream after the review?]
Add trace event balance_dirty_state for showing the global dirty page
counts and thresholds at each global_dirty_limits() invocation. This
will cover the callers throttle_vm_writeout(), over_bground_thresh()
and each balance_dirty_pages() loop.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
include/trace/events/writeback.h | 36 +++++++++++++++++++++++++++++
mm/page-writeback.c | 1
2 files changed, 37 insertions(+)
--- linux-next.orig/mm/page-writeback.c 2011-06-10 21:52:34.000000000 +0800
+++ linux-next/mm/page-writeback.c 2011-06-10 22:08:26.000000000 +0800
@@ -430,6 +430,7 @@ void global_dirty_limits(unsigned long *
}
*pbackground = background;
*pdirty = dirty;
+ trace_global_dirty_state(background, dirty);
}
/**
--- linux-next.orig/include/trace/events/writeback.h 2011-06-10 21:52:34.000000000 +0800
+++ linux-next/include/trace/events/writeback.h 2011-06-10 22:25:33.000000000 +0800
@@ -187,6 +187,42 @@ TRACE_EVENT(writeback_queue_io,
__entry->moved)
);
+TRACE_EVENT(global_dirty_state,
+
+ TP_PROTO(unsigned long background_thresh,
+ unsigned long dirty_thresh
+ ),
+
+ TP_ARGS(background_thresh,
+ dirty_thresh
+ ),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, nr_dirty)
+ __field(unsigned long, nr_writeback)
+ __field(unsigned long, nr_unstable)
+ __field(unsigned long, background_thresh)
+ __field(unsigned long, dirty_thresh)
+ ),
+
+ TP_fast_assign(
+ __entry->nr_dirty = global_page_state(NR_FILE_DIRTY);
+ __entry->nr_writeback = global_page_state(NR_WRITEBACK);
+ __entry->nr_unstable = global_page_state(NR_UNSTABLE_NFS);
+ __entry->background_thresh = background_thresh;
+ __entry->dirty_thresh = dirty_thresh;
+ ),
+
+ TP_printk("dirty=%lu writeback=%lu unstable=%lu "
+ "bg_thresh=%lu thresh=%lu",
+ __entry->nr_dirty,
+ __entry->nr_writeback,
+ __entry->nr_unstable,
+ __entry->background_thresh,
+ __entry->dirty_thresh
+ )
+);
+
DECLARE_EVENT_CLASS(writeback_congest_waited_template,
TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
--
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