It is valuable to know how the dirty inodes are iterated and their IO size. "writeback_single_inode: bdi 8:0: ino=134246746 state=I_DIRTY_SYNC|I_SYNC age=414 index=0 to_write=1024 wrote=0" - "state" reflects inode->i_state at the end of writeback_single_inode() - "index" reflects mapping->writeback_index after the ->writepages() call - "to_write" is the wbc->nr_to_write at entrance of writeback_single_inode() - "wrote" is the number of pages actually written v2: add trace event writeback_single_inode_requeue as proposed by Dave. CC: Dave Chinner Signed-off-by: Wu Fengguang --- fs/fs-writeback.c | 4 + include/trace/events/writeback.h | 70 +++++++++++++++++++++++++++++ 2 files changed, 74 insertions(+) --- linux-next.orig/include/trace/events/writeback.h 2011-05-24 11:17:25.000000000 +0800 +++ linux-next/include/trace/events/writeback.h 2011-05-24 11:17:26.000000000 +0800 @@ -8,6 +8,19 @@ #include #include +#define show_inode_state(state) \ + __print_flags(state, "|", \ + {I_DIRTY_SYNC, "I_DIRTY_SYNC"}, \ + {I_DIRTY_DATASYNC, "I_DIRTY_DATASYNC"}, \ + {I_DIRTY_PAGES, "I_DIRTY_PAGES"}, \ + {I_NEW, "I_NEW"}, \ + {I_WILL_FREE, "I_WILL_FREE"}, \ + {I_FREEING, "I_FREEING"}, \ + {I_CLEAR, "I_CLEAR"}, \ + {I_SYNC, "I_SYNC"}, \ + {I_REFERENCED, "I_REFERENCED"} \ + ) + struct wb_writeback_work; DECLARE_EVENT_CLASS(writeback_work_class, @@ -184,6 +197,63 @@ DEFINE_EVENT(writeback_congest_waited_te TP_ARGS(usec_timeout, usec_delayed) ); +DECLARE_EVENT_CLASS(writeback_single_inode_template, + + TP_PROTO(struct inode *inode, + struct writeback_control *wbc, + unsigned long nr_to_write + ), + + TP_ARGS(inode, wbc, nr_to_write), + + TP_STRUCT__entry( + __array(char, name, 32) + __field(unsigned long, ino) + __field(unsigned long, state) + __field(unsigned long, age) + __field(unsigned long, writeback_index) + __field(long, nr_to_write) + __field(unsigned long, wrote) + ), + + TP_fast_assign( + strncpy(__entry->name, + dev_name(inode->i_mapping->backing_dev_info->dev), 32); + __entry->ino = inode->i_ino; + __entry->state = inode->i_state; + __entry->age = (jiffies - inode->dirtied_when) * + 1000 / HZ; + __entry->writeback_index = inode->i_mapping->writeback_index; + __entry->nr_to_write = nr_to_write; + __entry->wrote = nr_to_write - wbc->nr_to_write; + ), + + TP_printk("bdi %s: ino=%lu state=%s age=%lu " + "index=%lu to_write=%ld wrote=%lu", + __entry->name, + __entry->ino, + show_inode_state(__entry->state), + __entry->age, + __entry->writeback_index, + __entry->nr_to_write, + __entry->wrote + ) +); + +DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode_requeue, + TP_PROTO(struct inode *inode, + struct writeback_control *wbc, + unsigned long nr_to_write), + TP_ARGS(inode, wbc, nr_to_write) +); + +DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode, + TP_PROTO(struct inode *inode, + struct writeback_control *wbc, + unsigned long nr_to_write), + TP_ARGS(inode, wbc, nr_to_write) +); + #endif /* _TRACE_WRITEBACK_H */ /* This part must be outside protection */ --- linux-next.orig/fs/fs-writeback.c 2011-05-24 11:17:25.000000000 +0800 +++ linux-next/fs/fs-writeback.c 2011-05-24 11:17:26.000000000 +0800 @@ -346,6 +346,7 @@ writeback_single_inode(struct inode *ino struct writeback_control *wbc) { struct address_space *mapping = inode->i_mapping; + long nr_to_write = wbc->nr_to_write; unsigned dirty; int ret; @@ -368,6 +369,8 @@ writeback_single_inode(struct inode *ino */ if (wbc->sync_mode != WB_SYNC_ALL) { requeue_io(inode, wb); + trace_writeback_single_inode_requeue(inode, wbc, + nr_to_write); return 0; } @@ -467,6 +470,7 @@ writeback_single_inode(struct inode *ino } } inode_sync_complete(inode); + trace_writeback_single_inode(inode, wbc, nr_to_write); return ret; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/