[PATCH 11/12] writeback: introduce wbc.for_background

Wu Fengguang
2009-11-18T08:31:57Z

[-- Attachment #1: writeback-add-wbc-for_background.patch --]
[-- Type: text/plain, Size: 1728 bytes --]

It will lower the flush priority for NFS, and maybe more in future.

CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
fs/fs-writeback.c | 1 +
fs/nfs/write.c | 2 +-
include/linux/writeback.h | 1 +
3 files changed, 3 insertions(+), 1 deletion(-)

--- linux.orig/fs/fs-writeback.c 2009-11-18 16:26:04.000000000 +0800
+++ linux/fs/fs-writeback.c 2009-11-18 16:26:07.000000000 +0800
@@ -713,6 +713,7 @@ static long wb_writeback(struct bdi_writ
.sync_mode = args->sync_mode,
.older_than_this = NULL,
.for_kupdate = args->for_kupdate,
+ .for_background = args->for_background,
.range_cyclic = args->range_cyclic,
};
unsigned long oldest_jif;
--- linux.orig/include/linux/writeback.h 2009-11-18 16:25:28.000000000 +0800
+++ linux/include/linux/writeback.h 2009-11-18 16:26:07.000000000 +0800
@@ -76,6 +76,7 @@ struct writeback_control {
unsigned nonblocking:1; /* Don't get stuck on request queues */
unsigned encountered_congestion:1; /* An output: a queue is full */
unsigned for_kupdate:1; /* A kupdate writeback */
+ 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.orig/fs/nfs/write.c 2009-11-18 16:25:28.000000000 +0800
+++ linux/fs/nfs/write.c 2009-11-18 16:26:07.000000000 +0800
@@ -178,7 +178,7 @@ static int wb_priority(struct writeback_
{
if (wbc->for_reclaim)
return FLUSH_HIGHPRI | FLUSH_STABLE;
- if (wbc->for_kupdate)
+ if (wbc->for_kupdate || wbc->for_background)
return FLUSH_LOWPRI;
return 0;
}