It provides critical information to understand how various throttle
bandwidths are updated.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
include/trace/events/writeback.h | 51 +++++++++++++++++++++++++++--
mm/page-writeback.c | 1
2 files changed, 49 insertions(+), 3 deletions(-)
--- linux-next.orig/mm/page-writeback.c 2011-04-16 11:28:21.000000000 +0800
+++ linux-next/mm/page-writeback.c 2011-04-16 11:28:27.000000000 +0800
@@ -974,6 +974,7 @@ adjust:
bdi->dirty_ratelimit = bw;
out:
bdi_update_reference_ratelimit(bdi, ref_bw);
+ trace_dirty_ratelimit(bdi, dirty_bw, pos_bw, ref_bw);
}
void bdi_update_bandwidth(struct backing_dev_info *bdi,
--- linux-next.orig/include/trace/events/writeback.h 2011-04-16 11:28:17.000000000 +0800
+++ linux-next/include/trace/events/writeback.h 2011-04-16 11:28:27.000000000 +0800
@@ -147,11 +147,56 @@ DEFINE_EVENT(wbc_class, name, \
DEFINE_WBC_EVENT(wbc_writeback_start);
DEFINE_WBC_EVENT(wbc_writeback_written);
DEFINE_WBC_EVENT(wbc_writeback_wait);
-DEFINE_WBC_EVENT(wbc_balance_dirty_start);
-DEFINE_WBC_EVENT(wbc_balance_dirty_written);
-DEFINE_WBC_EVENT(wbc_balance_dirty_wait);
DEFINE_WBC_EVENT(wbc_writepage);
+#define KBps(x) ((x) << (PAGE_SHIFT - 10))
+
+TRACE_EVENT(dirty_ratelimit,
+
+ TP_PROTO(struct backing_dev_info *bdi,
+ unsigned long dirty_bw,
+ unsigned long pos_bw,
+ unsigned long ref_bw),
+
+ TP_ARGS(bdi, dirty_bw, pos_bw, ref_bw),
+
+ TP_STRUCT__entry(
+ __array(char, bdi, 32)
+ __field(unsigned long, write_bw)
+ __field(unsigned long, avg_bw)
+ __field(unsigned long, dirty_bw)
+ __field(unsigned long, base_bw)
+ __field(unsigned long, pos_bw)
+ __field(unsigned long, ref_bw)
+ __field(unsigned long, avg_ref_bw)
+ ),
+
+ TP_fast_assign(
+ strlcpy(__entry->bdi, dev_name(bdi->dev), 32);
+ __entry->write_bw = KBps(bdi->write_bandwidth);
+ __entry->avg_bw = KBps(bdi->avg_write_bandwidth);
+ __entry->dirty_bw = KBps(dirty_bw);
+ __entry->base_bw = KBps(bdi->dirty_ratelimit);
+ __entry->pos_bw = KBps(pos_bw);
+ __entry->ref_bw = KBps(ref_bw);
+ __entry->avg_ref_bw = KBps(bdi->reference_ratelimit);
+ ),
+
+
+ TP_printk("bdi %s: "
+ "write_bw=%lu awrite_bw=%lu dirty_bw=%lu "
+ "base_bw=%lu pos_bw=%lu ref_bw=%lu aref_bw=%lu",
+ __entry->bdi,
+ __entry->write_bw, /* write bandwidth */
+ __entry->avg_bw, /* avg write bandwidth */
+ __entry->dirty_bw, /* dirty bandwidth */
+ __entry->base_bw, /* dirty ratelimit on each task */
+ __entry->pos_bw, /* position control ratelimit */
+ __entry->ref_bw, /* the reference ratelimit */
+ __entry->avg_ref_bw /* smoothed reference ratelimit */
+ )
+);
+
DECLARE_EVENT_CLASS(writeback_congest_waited_template,
TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
--
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