Introduce writeback_control.more_io to indicate that more I/O is
scheduled for this wakeup of pdflush.
Note that more_io is only updated on the _visited_ superblocks,
which prevents pdflush deamons from interfering with one another.
Cc: Michael Rubin <mrubin@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Fengguang Wu <wfg@xxxxxxxxxxxxxxxx>
---
fs/fs-writeback.c | 6 +++++-
include/linux/writeback.h | 1 +
2 files changed, 6 insertions(+), 1 deletion(-)
--- linux-mm.orig/fs/fs-writeback.c
+++ linux-mm/fs/fs-writeback.c
@@ -472,8 +472,12 @@ int generic_sync_sb_inodes(struct super_
iput(inode);
cond_resched();
spin_lock(&inode_lock);
- if (wbc->nr_to_write <= 0)
+ if (wbc->nr_to_write <= 0) {
+ wbc->more_io = 1;
break;
+ }
+ if (!list_empty(&sb->s_more_io))
+ wbc->more_io = 1;
}
spin_unlock(&inode_lock);
return ret; /* Leave any unwritten inodes on s_io */
--- linux-mm.orig/include/linux/writeback.h
+++ linux-mm/include/linux/writeback.h
@@ -62,6 +62,7 @@ struct writeback_control {
unsigned for_reclaim:1; /* Invoked from the page allocator */
unsigned for_writepages:1; /* This is a writepages() call */
unsigned range_cyclic:1; /* range_start is cyclic */
+ unsigned more_io:1; /* more io to be dispatched */
};
/*
--
-
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