[PATCHv5 08/15] writeback: move last_active to bdi

Artem Bityutskiy
2010-07-25T08:31:52Z

Currently bdi threads use local variable 'last_active' which stores last time
when the bdi thread did some useful work. Move this local variable to 'struct
bdi_writeback'. This is just a preparation for the further patches which will
make the forker thread decide when bdi threads should be killed.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/fs-writeback.c | 6 +++---
include/linux/backing-dev.h | 13 +++++++------
2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index eaef5c9..53e1028 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -800,12 +800,12 @@ int bdi_writeback_thread(void *data)
{
struct bdi_writeback *wb = data;
struct backing_dev_info *bdi = wb->bdi;
- unsigned long last_active = jiffies;
unsigned long wait_jiffies = -1UL;
long pages_written;

current->flags |= PF_FLUSHER | PF_SWAPWRITE;
set_freezable();
+ wb->last_active = jiffies;

/*
* Our parent may run at a different priority, just set us to normal
@@ -827,7 +827,7 @@ int bdi_writeback_thread(void *data)
trace_writeback_pages_written(pages_written);

if (pages_written)
- last_active = jiffies;
+ wb->last_active = jiffies;
else if (wait_jiffies != -1UL) {
unsigned long max_idle;

@@ -837,7 +837,7 @@ int bdi_writeback_thread(void *data)
* recreated automatically.
*/
max_idle = max(5UL * 60 * HZ, wait_jiffies);
- if (time_after(jiffies, max_idle + last_active))
+ if (time_after(jiffies, max_idle + wb->last_active))
break;
}

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 95ecb2b..71b6223 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -45,15 +45,16 @@ enum bdi_stat_item {
#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))

struct bdi_writeback {
- struct backing_dev_info *bdi; /* our parent bdi */
+ struct backing_dev_info *bdi; /* our parent bdi */
unsigned int nr;

- unsigned long last_old_flush; /* last old data flush */
+ unsigned long last_old_flush; /* last old data flush */
+ unsigned long last_active; /* last time bdi thread was active */

- struct task_struct *task; /* writeback thread */
- struct list_head b_dirty; /* dirty inodes */
- struct list_head b_io; /* parked for writeback */
- struct list_head b_more_io; /* parked for more writeback */
+ struct task_struct *task; /* writeback thread */
+ struct list_head b_dirty; /* dirty inodes */
+ struct list_head b_io; /* parked for writeback */
+ struct list_head b_more_io; /* parked for more writeback */
};

struct backing_dev_info {
--
1.7.1.1