From: Dave Chinner <dchinner@xxxxxxxxxx> Tracing high level background writeback events is good, but it doesn't give the entire picture. Add IO dispatched by foreground throttling to the writeback events. Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> --- fs/fs-writeback.c | 5 ++ include/trace/events/writeback.h | 77 ++++++++++++++++++++++++++++++++++++++ mm/page-writeback.c | 4 ++ 3 files changed, 86 insertions(+), 0 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 3f5f0a5..5214b61 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -752,7 +752,11 @@ static long wb_writeback(struct bdi_writeback *wb, wbc.more_io = 0; wbc.nr_to_write = MAX_WRITEBACK_PAGES; wbc.pages_skipped = 0; + + trace_wbc_writeback_start(&wbc); writeback_inodes_wb(wb, &wbc); + trace_wbc_writeback_written(&wbc); + args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; @@ -780,6 +784,7 @@ static long wb_writeback(struct bdi_writeback *wb, if (!list_empty(&wb->b_more_io)) { inode = list_entry(wb->b_more_io.prev, struct inode, i_list); + trace_wbc_writeback_wait(&wbc); inode_wait_for_writeback(inode); } spin_unlock(&inode_lock); diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h index df76457..02f34a5 100644 --- a/include/trace/events/writeback.h +++ b/include/trace/events/writeback.h @@ -165,6 +165,83 @@ TRACE_EVENT(writeback_bdi_register, TP_printk("%s: %s", __entry->name, __entry->start ? "registered" : "unregistered") ); + +/* pass flags explicitly */ +DECLARE_EVENT_CLASS(wbc_class, + TP_PROTO(struct writeback_control *wbc), + TP_ARGS(wbc), + TP_STRUCT__entry( + __field(unsigned int, wbc) + __array(char, name, 16) + __field(long, nr_to_write) + __field(long, pages_skipped) + __field(int, sb) + __field(int, sync_mode) + __field(int, nonblocking) + __field(int, encountered_congestion) + __field(int, for_kupdate) + __field(int, for_background) + __field(int, for_reclaim) + __field(int, range_cyclic) + __field(int, more_io) + __field(unsigned long, older_than_this) + __field(long, range_start) + __field(long, range_end) + ), + + TP_fast_assign( + char *__name = "(none)"; + + __entry->wbc = (unsigned long)wbc & 0xffff; + if (wbc->bdi) + strncpy(__entry->name, dev_name(wbc->bdi->dev), 16); + else + strncpy(__entry->name, __name, 16); + __entry->nr_to_write = wbc->nr_to_write; + __entry->pages_skipped = wbc->pages_skipped; + __entry->sb = !!wbc->sb; + __entry->sync_mode = wbc->sync_mode; + __entry->for_kupdate = wbc->for_kupdate; + __entry->for_background = wbc->for_background; + __entry->for_reclaim = wbc->for_reclaim; + __entry->range_cyclic = wbc->range_cyclic; + __entry->more_io = wbc->more_io; + __entry->older_than_this = wbc->older_than_this ? + *wbc->older_than_this : 0; + __entry->range_start = (long)wbc->range_start; + __entry->range_end = (long)wbc->range_end; + ), + + TP_printk("dev %s wbc=%x towrt=%ld skip=%ld sb=%d mode=%d kupd=%d " + "bgrd=%d reclm=%d cyclic=%d more=%d older=0x%lx " + "start=0x%lx end=0x%lx", + __entry->name, + __entry->wbc, + __entry->nr_to_write, + __entry->pages_skipped, + __entry->sb, + __entry->sync_mode, + __entry->for_kupdate, + __entry->for_background, + __entry->for_reclaim, + __entry->range_cyclic, + __entry->more_io, + __entry->older_than_this, + __entry->range_start, + __entry->range_end) +) + +#define DEFINE_WBC_EVENT(name) \ +DEFINE_EVENT(wbc_class, name, \ + TP_PROTO(struct writeback_control *wbc), \ + TP_ARGS(wbc)) +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); + #endif /* _TRACE_WRITEBACK_H */ /* This part must be outside protection */ diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 0b19943..d45f59e 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 @@ -536,11 +537,13 @@ static void balance_dirty_pages(struct address_space *mapping, * threshold otherwise wait until the disk writes catch * up. */ + trace_wbc_balance_dirty_start(&wbc); if (bdi_nr_reclaimable > bdi_thresh) { writeback_inodes_wbc(&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); } /* @@ -566,6 +569,7 @@ 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); __set_current_state(TASK_INTERRUPTIBLE); io_schedule_timeout(pause); -- 1.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html