From: Wu Fengguang on
When wbc.more_io was first introduced, it indicates whether there are
at least one superblock whose s_more_io contains more IO work. Now with
the per-bdi writeback, it can be replaced with a simple b_more_io test.

Acked-by: Jan Kara <jack(a)suse.cz>
Acked-by: Mel Gorman <mel(a)csn.ul.ie>
CC: Minchan Kim <minchan.kim(a)gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu(a)intel.com>
---
fs/fs-writeback.c | 9 ++-------
include/linux/writeback.h | 1 -
include/trace/events/ext4.h | 5 +----
include/trace/events/writeback.h | 5 +----
4 files changed, 4 insertions(+), 16 deletions(-)

--- linux-next.orig/fs/fs-writeback.c 2010-08-05 23:28:10.000000000 +0800
+++ linux-next/fs/fs-writeback.c 2010-08-05 23:28:11.000000000 +0800
@@ -516,12 +516,8 @@ static int writeback_sb_inodes(struct su
iput(inode);
cond_resched();
spin_lock(&inode_lock);
- if (wbc->nr_to_write <= 0) {
- wbc->more_io = 1;
+ if (wbc->nr_to_write <= 0)
return 1;
- }
- if (!list_empty(&wb->b_more_io))
- wbc->more_io = 1;
}
/* b_io is empty */
return 1;
@@ -631,7 +627,6 @@ static long wb_writeback(struct bdi_writ
if (work->for_background && !over_bground_thresh())
break;

- wbc.more_io = 0;
wbc.nr_to_write = MAX_WRITEBACK_PAGES;
wbc.pages_skipped = 0;

@@ -653,7 +648,7 @@ static long wb_writeback(struct bdi_writ
/*
* Didn't write everything and we don't have more IO, bail
*/
- if (!wbc.more_io)
+ if (list_empty(&wb->b_more_io))
break;
/*
* Did we write something? Try for more
--- linux-next.orig/include/linux/writeback.h 2010-08-05 23:28:10.000000000 +0800
+++ linux-next/include/linux/writeback.h 2010-08-05 23:28:11.000000000 +0800
@@ -49,7 +49,6 @@ struct writeback_control {
unsigned for_background:1; /* A background writeback */
unsigned for_reclaim:1; /* Invoked from the page allocator */
unsigned range_cyclic:1; /* range_start is cyclic */
- unsigned more_io:1; /* more io to be dispatched */
};

/*
--- linux-next.orig/include/trace/events/writeback.h 2010-08-05 23:28:10.000000000 +0800
+++ linux-next/include/trace/events/writeback.h 2010-08-05 23:28:11.000000000 +0800
@@ -100,7 +100,6 @@ DECLARE_EVENT_CLASS(wbc_class,
__field(int, for_background)
__field(int, for_reclaim)
__field(int, range_cyclic)
- __field(int, more_io)
__field(long, range_start)
__field(long, range_end)
),
@@ -114,13 +113,12 @@ DECLARE_EVENT_CLASS(wbc_class,
__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->range_start = (long)wbc->range_start;
__entry->range_end = (long)wbc->range_end;
),

TP_printk("bdi %s: towrt=%ld skip=%ld mode=%d kupd=%d "
- "bgrd=%d reclm=%d cyclic=%d more=%d "
+ "bgrd=%d reclm=%d cyclic=%d "
"start=0x%lx end=0x%lx",
__entry->name,
__entry->nr_to_write,
@@ -130,7 +128,6 @@ DECLARE_EVENT_CLASS(wbc_class,
__entry->for_background,
__entry->for_reclaim,
__entry->range_cyclic,
- __entry->more_io,
__entry->range_start,
__entry->range_end)
)
--- linux-next.orig/include/trace/events/ext4.h 2010-08-05 23:27:33.000000000 +0800
+++ linux-next/include/trace/events/ext4.h 2010-08-05 23:28:11.000000000 +0800
@@ -305,7 +305,6 @@ TRACE_EVENT(ext4_da_writepages_result,
__field( int, ret )
__field( int, pages_written )
__field( long, pages_skipped )
- __field( char, more_io )
__field( pgoff_t, writeback_index )
),

@@ -315,15 +314,13 @@ TRACE_EVENT(ext4_da_writepages_result,
__entry->ret = ret;
__entry->pages_written = pages_written;
__entry->pages_skipped = wbc->pages_skipped;
- __entry->more_io = wbc->more_io;
__entry->writeback_index = inode->i_mapping->writeback_index;
),

- TP_printk("dev %s ino %lu ret %d pages_written %d pages_skipped %ld more_io %d writeback_index %lu",
+ TP_printk("dev %s ino %lu ret %d pages_written %d pages_skipped %ld writeback_index %lu",
jbd2_dev_to_name(__entry->dev),
(unsigned long) __entry->ino, __entry->ret,
__entry->pages_written, __entry->pages_skipped,
- __entry->more_io,
(unsigned long) __entry->writeback_index)
);



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