Lots of lenthy tests.. Let's compact the names
*_dirty3 = dirty + writeback + unstable
balance_dirty_pages() only cares about the above dirty sum except
in one place -- on starting background writeback.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
mm/page-writeback.c | 34 ++++++++++++++++------------------
1 file changed, 16 insertions(+), 18 deletions(-)
--- linux-next.orig/mm/page-writeback.c 2010-09-12 13:30:38.000000000 +0800
+++ linux-next/mm/page-writeback.c 2010-09-12 13:34:04.000000000 +0800
@@ -493,8 +493,8 @@ start_over:
static void balance_dirty_pages(struct address_space *mapping,
unsigned long pages_dirtied)
{
- long nr_reclaimable, bdi_nr_reclaimable;
- long nr_writeback, bdi_nr_writeback;
+ long nr_reclaimable;
+ long nr_dirty3, bdi_dirty3;
long bdi_prev_dirty3 = 0;
unsigned long background_thresh;
unsigned long dirty_thresh;
@@ -518,7 +518,7 @@ static void balance_dirty_pages(struct a
*/
nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS);
- nr_writeback = global_page_state(NR_WRITEBACK);
+ nr_dirty3 = nr_reclaimable + global_page_state(NR_WRITEBACK);
global_dirty_limits(&background_thresh, &dirty_thresh);
@@ -529,7 +529,7 @@ static void balance_dirty_pages(struct a
*/
thresh = (background_thresh + dirty_thresh) / 2;
thresh = thresh * vm_dirty_pressure / VM_DIRTY_PRESSURE;
- if (nr_reclaimable + nr_writeback <= thresh)
+ if (nr_dirty3 <= thresh)
break;
task_dirties_fraction(current, &numerator, &denominator);
@@ -548,11 +548,11 @@ static void balance_dirty_pages(struct a
* deltas.
*/
if (bdi_thresh < 2*bdi_stat_error(bdi)) {
- bdi_nr_reclaimable = bdi_stat_sum(bdi, BDI_RECLAIMABLE);
- bdi_nr_writeback = bdi_stat_sum(bdi, BDI_WRITEBACK);
+ bdi_dirty3 = bdi_stat_sum(bdi, BDI_RECLAIMABLE) +
+ bdi_stat_sum(bdi, BDI_WRITEBACK);
} else {
- bdi_nr_reclaimable = bdi_stat(bdi, BDI_RECLAIMABLE);
- bdi_nr_writeback = bdi_stat(bdi, BDI_WRITEBACK);
+ bdi_dirty3 = bdi_stat(bdi, BDI_RECLAIMABLE) +
+ bdi_stat(bdi, BDI_WRITEBACK);
}
/*
@@ -563,11 +563,10 @@ static void balance_dirty_pages(struct a
* So offer a complementary way to break out of the loop when
* enough bdi pages have been cleaned during our pause time.
*/
- if (nr_reclaimable + nr_writeback <= dirty_thresh &&
- bdi_prev_dirty3 - (bdi_nr_reclaimable + bdi_nr_writeback) >
- (long)pages_dirtied * 8)
+ if (nr_dirty3 <= dirty_thresh &&
+ bdi_prev_dirty3 - bdi_dirty3 > (long)pages_dirtied * 8)
break;
- bdi_prev_dirty3 = bdi_nr_reclaimable + bdi_nr_writeback;
+ bdi_prev_dirty3 = bdi_dirty3;
thresh = bdi_thresh - bdi_thresh / DIRTY_SOFT_THROTTLE_RATIO;
@@ -584,13 +583,13 @@ static void balance_dirty_pages(struct a
else if (thresh > bw)
thresh = bw;
}
- if (bdi_nr_reclaimable + bdi_nr_writeback <= thresh)
+ if (bdi_dirty3 <= thresh)
goto check_exceeded;
bdi_update_write_bandwidth(bdi, &bw_time, &bw_written);
- gap = bdi_thresh > (bdi_nr_reclaimable + bdi_nr_writeback) ?
- bdi_thresh - (bdi_nr_reclaimable + bdi_nr_writeback) : 0;
+ gap = bdi_thresh > bdi_dirty3 ?
+ bdi_thresh - bdi_dirty3 : 0;
bw = bdi->write_bandwidth * gap / (bdi_thresh - thresh + 1);
@@ -622,9 +621,8 @@ check_exceeded:
* bdi or process from holding back light ones; The latter is
* the last resort safeguard.
*/
- dirty_exceeded =
- (bdi_nr_reclaimable + bdi_nr_writeback > bdi_thresh)
- || (nr_reclaimable + nr_writeback > dirty_thresh);
+ dirty_exceeded = (bdi_dirty3 > bdi_thresh) ||
+ (nr_dirty3 > dirty_thresh);
if (!dirty_exceeded)
break;
--
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