From: Bart Samwel <bart@samwel.tk>
Writebacks on writes can be implemented in submit_bio for writes as well,
removing this code from balance_dirty_pages.
---
drivers/block/ll_rw_blk.c | 6 ++++
mm/page-writeback.c | 56 ++++++++++++++++++----------------------------
2 files changed, 29 insertions(+), 33 deletions(-)
diff -puN drivers/block/ll_rw_blk.c~laptop-mode-simplification drivers/block/ll_rw_blk.c
--- 25/drivers/block/ll_rw_blk.c~laptop-mode-simplification 2004-02-16 17:49:27.000000000 -0800
+++ 25-akpm/drivers/block/ll_rw_blk.c 2004-02-16 17:49:27.000000000 -0800
@@ -2608,6 +2608,12 @@ void end_that_request_last(struct reques
unsigned long duration = jiffies - req->start_time;
switch (rq_data_dir(req)) {
case WRITE:
+ /*
+ * schedule the writeout of pending dirty data when the disk is idle.
+ * (Writeback is not postponed by writes, only by reads.)
+ */
+ if (unlikely(laptop_mode))
+ disk_is_spun_up(0);
disk_stat_inc(disk, writes);
disk_stat_add(disk, write_ticks, duration);
break;
diff -puN mm/page-writeback.c~laptop-mode-simplification mm/page-writeback.c
--- 25/mm/page-writeback.c~laptop-mode-simplification 2004-02-16 17:49:27.000000000 -0800
+++ 25-akpm/mm/page-writeback.c 2004-02-16 17:49:27.000000000 -0800
@@ -206,17 +206,6 @@ static void balance_dirty_pages(struct a
if (nr_reclaimable + ps.nr_writeback <= dirty_thresh)
dirty_exceeded = 0;
- if (unlikely(laptop_mode) && pages_written > 0) {
- /*
- * Schedule full writeout to happen soon. We don't postpone
- * previously scheduled full writeouts, otherwise a writing
- * process throttled by balance_dirty_pages will be able to
- * postpone the full writeout indefinitely, keeping the disk
- * spun up as a result.
- */
- disk_is_spun_up(0);
- }
-
if (!unlikely(laptop_mode) && !writeback_in_progress(bdi) && nr_reclaimable > background_thresh)
pdflush_operation(background_writeout, 0);
}
@@ -311,7 +300,17 @@ int wakeup_bdflush(long nr_pages)
return pdflush_operation(background_writeout, nr_pages);
}
-static struct timer_list wb_timer;
+
+static void wb_timer_fn(unsigned long unused);
+
+/*
+ * Both timers share the same handler
+ */
+static struct timer_list wb_timer =
+ TIMER_INITIALIZER(wb_timer_fn, 0, 0);
+static struct timer_list laptop_mode_wb_timer =
+ TIMER_INITIALIZER(wb_timer_fn, 0, 0);
+
/*
* Periodic writeback of "old" data.
@@ -368,15 +367,12 @@ static void wb_kupdate(unsigned long arg
}
if (time_before(next_jif, jiffies + HZ))
next_jif = jiffies + HZ;
- if (laptop_mode) {
- sync_inodes(0);
- sync_filesystems(0);
- DQUOT_SYNC(NULL);
- }
if (dirty_writeback_centisecs)
mod_timer(&wb_timer, next_jif);
+ del_timer(&laptop_mode_wb_timer); /* May have been set as a result of our writes. */
}
+
/*
* sysctl handler for /proc/sys/vm/dirty_writeback_centisecs
*/
@@ -393,19 +389,6 @@ int dirty_writeback_centisecs_handler(ct
return 0;
}
-static void wb_timer_fn(unsigned long unused)
-{
- if (pdflush_operation(wb_kupdate, 0) < 0)
- mod_timer(&wb_timer, jiffies + HZ); /* delay 1 second */
-
-}
-
-/*
- * Both timers share the same handler
- */
-static struct timer_list laptop_mode_wb_timer =
- TIMER_INITIALIZER(wb_timer_fn, 0, 0);
-
/*
* We've spun up the disk and we're in laptop mode: schedule writeback
* of all dirty data in 5 seconds.
@@ -422,6 +405,16 @@ void disk_is_spun_up(int postpone_writeb
/*
+ * Handler for wb_timer and laptop_mode_wb_timer.
+ */
+static void wb_timer_fn(unsigned long unused)
+{
+ if (pdflush_operation(wb_kupdate, 0) < 0)
+ mod_timer(&wb_timer, jiffies + HZ); /* delay 1 second */
+}
+
+
+/*
* If ratelimit_pages is too high then we can get into dirty-data overload
* if a large number of processes all perform writes at the same time.
* If it is too low then SMP machines will call the (expensive) get_page_state
@@ -480,10 +473,7 @@ void __init page_writeback_init(void)
vm_dirty_ratio /= 100;
}
- init_timer(&wb_timer);
wb_timer.expires = jiffies + (dirty_writeback_centisecs * HZ) / 100;
- wb_timer.data = 0;
- wb_timer.function = wb_timer_fn;
add_timer(&wb_timer);
set_ratelimit();
_