[PATCH 5/6] VM: Use per-bdi unstable accounting to improve use of wbc->force_commit

Trond Myklebust
2010-01-06T20:59:32Z

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Jan Kara <jack@suse.cz>
---

mm/page-writeback.c | 13 +++++++------
1 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index d90a0db..c537543 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -487,7 +487,6 @@ static void balance_dirty_pages(struct address_space *mapping,
{
long nr_reclaimable, bdi_nr_reclaimable;
long nr_writeback, bdi_nr_writeback;
- long nr_unstable_nfs;
unsigned long background_thresh;
unsigned long dirty_thresh;
unsigned long bdi_thresh;
@@ -504,18 +503,20 @@ static void balance_dirty_pages(struct address_space *mapping,
.nr_to_write = write_chunk,
.range_cyclic = 1,
};
+ long bdi_nr_unstable = 0;

get_dirty_limits(&background_thresh, &dirty_thresh,
&bdi_thresh, bdi);

- nr_unstable_nfs = global_page_state(NR_UNSTABLE_NFS);
nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
- nr_unstable_nfs;
+ global_page_state(NR_UNSTABLE_NFS);
nr_writeback = global_page_state(NR_WRITEBACK);

bdi_nr_reclaimable = bdi_stat(bdi, BDI_DIRTY);
- if (bdi_cap_account_unstable(bdi))
- bdi_nr_reclaimable += bdi_stat(bdi, BDI_UNSTABLE);
+ if (bdi_cap_account_unstable(bdi)) {
+ bdi_nr_unstable = bdi_stat(bdi, BDI_UNSTABLE);
+ bdi_nr_reclaimable += bdi_nr_unstable;
+ }
bdi_nr_writeback = bdi_stat(bdi, BDI_WRITEBACK);

if (bdi_nr_reclaimable + bdi_nr_writeback <= bdi_thresh)
@@ -545,7 +546,7 @@ static void balance_dirty_pages(struct address_space *mapping,
if (bdi_nr_reclaimable > bdi_thresh) {
wbc.force_commit = 0;
/* Force NFS to also free up unstable writes. */
- if (nr_unstable_nfs > nr_reclaimable / 2)
+ if (bdi_nr_unstable > bdi_nr_reclaimable / 2)
wbc.force_commit = 1;

writeback_inodes_wbc(&wbc);