[PATCH 33/47] writeback: trace global dirty page states

Wu Fengguang
2010-12-13T06:55:35Z

[-- Attachment #1: writeback-trace-global-dirty-states.patch --]
[-- Type: text/plain, Size: 3410 bytes --]

Add trace balance_dirty_state for showing the global dirty page counts
and thresholds at each balance_dirty_pages() loop.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
include/trace/events/writeback.h | 57 +++++++++++++++++++++++++++++
mm/page-writeback.c | 15 ++++++-
2 files changed, 69 insertions(+), 3 deletions(-)

--- linux-next.orig/mm/page-writeback.c 2010-12-09 12:24:49.000000000 +0800
+++ linux-next/mm/page-writeback.c 2010-12-09 12:24:52.000000000 +0800
@@ -720,12 +720,21 @@ static void balance_dirty_pages(struct a
* written to the server's write cache, but has not yet
* been flushed to permanent storage.
*/
- nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
- global_page_state(NR_UNSTABLE_NFS);
- nr_dirty = nr_reclaimable + global_page_state(NR_WRITEBACK);
+ nr_reclaimable = global_page_state(NR_FILE_DIRTY);
+ bdi_dirty = global_page_state(NR_UNSTABLE_NFS);
+ nr_dirty = global_page_state(NR_WRITEBACK);

global_dirty_limits(&background_thresh, &dirty_thresh);

+ trace_balance_dirty_state(mapping,
+ nr_reclaimable,
+ nr_dirty,
+ bdi_dirty,
+ background_thresh,
+ dirty_thresh);
+ nr_reclaimable += bdi_dirty;
+ nr_dirty += nr_reclaimable;
+
/*
* Throttle it only when the background writeback cannot
* catch-up. This avoids (excessively) small writeouts
--- linux-next.orig/include/trace/events/writeback.h 2010-12-09 12:24:49.000000000 +0800
+++ linux-next/include/trace/events/writeback.h 2010-12-09 12:24:52.000000000 +0800
@@ -149,6 +149,63 @@ DEFINE_WBC_EVENT(wbc_writeback_written);
DEFINE_WBC_EVENT(wbc_writeback_wait);
DEFINE_WBC_EVENT(wbc_writepage);

+TRACE_EVENT(balance_dirty_state,
+
+ TP_PROTO(struct address_space *mapping,
+ unsigned long nr_dirty,
+ unsigned long nr_writeback,
+ unsigned long nr_unstable,
+ unsigned long background_thresh,
+ unsigned long dirty_thresh
+ ),
+
+ TP_ARGS(mapping,
+ nr_dirty,
+ nr_writeback,
+ nr_unstable,
+ background_thresh,
+ dirty_thresh
+ ),
+
+ TP_STRUCT__entry(
+ __array(char, bdi, 32)
+ __field(unsigned long, ino)
+ __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)
+ __field(unsigned long, task_dirtied_pause)
+ ),
+
+ TP_fast_assign(
+ strlcpy(__entry->bdi,
+ dev_name(mapping->backing_dev_info->dev), 32);
+ __entry->ino = mapping->host->i_ino;
+ __entry->nr_dirty = nr_dirty;
+ __entry->nr_writeback = nr_writeback;
+ __entry->nr_unstable = nr_unstable;
+ __entry->background_thresh = background_thresh;
+ __entry->dirty_thresh = dirty_thresh;
+ __entry->task_dirtied_pause = current->nr_dirtied_pause;
+ ),
+
+ TP_printk("bdi %s: dirty=%lu wb=%lu unstable=%lu "
+ "bg_thresh=%lu thresh=%lu gap=%ld "
+ "poll_thresh=%lu ino=%lu",
+ __entry->bdi,
+ __entry->nr_dirty,
+ __entry->nr_writeback,
+ __entry->nr_unstable,
+ __entry->background_thresh,
+ __entry->dirty_thresh,
+ __entry->dirty_thresh - __entry->nr_dirty -
+ __entry->nr_writeback - __entry->nr_unstable,
+ __entry->task_dirtied_pause,
+ __entry->ino
+ )
+);
+
#define KBps(x) ((x) << (PAGE_SHIFT - 10))
#define BDP_PERCENT(a, b, c) ((__entry->a - __entry->b) * 100 * c + \
__entry->bdi_limit/2) / (__entry->bdi_limit|1)