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authorDave Chinner <dchinner@redhat.com>2010-07-07 07:24:07 +0400
committerJens Axboe <jaxboe@fusionio.com>2010-08-07 20:24:25 +0400
commit028c2dd184c097809986684f2f0627eea5529fea (patch)
treef6eb9e30a24d73597e5ce2a65b4638e9d1947504 /mm/page-writeback.c
parent455b2864686d3591b3b2f39eb46290c95f76471f (diff)
downloadlinux-028c2dd184c097809986684f2f0627eea5529fea.tar.xz
writeback: Add tracing to balance_dirty_pages
Tracing high level background writeback events is good, but it doesn't give the entire picture. Add visibility into write throttling to catch IO dispatched by foreground throttling of processing dirtying lots of pages. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 37498ef61548..d556cd829af6 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -34,6 +34,7 @@
#include <linux/syscalls.h>
#include <linux/buffer_head.h>
#include <linux/pagevec.h>
+#include <trace/events/writeback.h>
/*
* After a CPU has dirtied this many pages, balance_dirty_pages_ratelimited
@@ -535,11 +536,13 @@ static void balance_dirty_pages(struct address_space *mapping,
* threshold otherwise wait until the disk writes catch
* up.
*/
+ trace_wbc_balance_dirty_start(&wbc, bdi);
if (bdi_nr_reclaimable > bdi_thresh) {
writeback_inodes_wb(&bdi->wb, &wbc);
pages_written += write_chunk - wbc.nr_to_write;
get_dirty_limits(&background_thresh, &dirty_thresh,
&bdi_thresh, bdi);
+ trace_wbc_balance_dirty_written(&wbc, bdi);
}
/*
@@ -565,6 +568,7 @@ static void balance_dirty_pages(struct address_space *mapping,
if (pages_written >= write_chunk)
break; /* We've done our duty */
+ trace_wbc_balance_dirty_wait(&wbc, bdi);
__set_current_state(TASK_INTERRUPTIBLE);
io_schedule_timeout(pause);