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authorTejun Heo <tj@kernel.org>2015-05-23 00:13:28 +0300
committerJens Axboe <axboe@fb.com>2015-06-02 17:33:34 +0300
commita88a341a73be4ef035ca26170c849f002797da27 (patch)
tree3b9ba08daa3fdfb00d02ba21dfbce702a03826bc /mm/backing-dev.c
parent93f78d882865cb90020d0f80a9523c99cf46924c (diff)
downloadlinux-a88a341a73be4ef035ca26170c849f002797da27.tar.xz
writeback: move bandwidth related fields from backing_dev_info into bdi_writeback
Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) and the role of the separation is unclear. For cgroup support for writeback IOs, a bdi will be updated to host multiple wb's where each wb serves writeback IOs of a different cgroup on the bdi. To achieve that, a wb should carry all states necessary for servicing writeback IOs for a cgroup independently. This patch moves bandwidth related fields from backing_dev_info into bdi_writeback. * The moved fields are: bw_time_stamp, dirtied_stamp, written_stamp, write_bandwidth, avg_write_bandwidth, dirty_ratelimit, balanced_dirty_ratelimit, completions and dirty_exceeded. * writeback_chunk_size() and over_bground_thresh() now take @wb instead of @bdi. * bdi_writeout_fraction(bdi, ...) -> wb_writeout_fraction(wb, ...) bdi_dirty_limit(bdi, ...) -> wb_dirty_limit(wb, ...) bdi_position_ration(bdi, ...) -> wb_position_ratio(wb, ...) bdi_update_writebandwidth(bdi, ...) -> wb_update_write_bandwidth(wb, ...) [__]bdi_update_bandwidth(bdi, ...) -> [__]wb_update_bandwidth(wb, ...) bdi_{max|min}_pause(bdi, ...) -> wb_{max|min}_pause(wb, ...) bdi_dirty_limits(bdi, ...) -> wb_dirty_limits(wb, ...) * Init/exits of the relocated fields are moved to bdi_wb_init/exit() respectively. Note that explicit zeroing is dropped in the process as wb's are cleared in entirety anyway. * As there's still only one bdi_writeback per backing_dev_info, all uses of bdi->stat[] are mechanically replaced with bdi->wb.stat[] introducing no behavior changes. v2: Typo in description fixed as suggested by Jan. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'mm/backing-dev.c')
-rw-r--r--mm/backing-dev.c45
1 files changed, 20 insertions, 25 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 7b1d1917b658..9a6c472ebd0b 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -66,7 +66,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
spin_unlock(&wb->list_lock);
global_dirty_limits(&background_thresh, &dirty_thresh);
- bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh);
+ bdi_thresh = wb_dirty_limit(wb, dirty_thresh);
#define K(x) ((x) << (PAGE_SHIFT - 10))
seq_printf(m,
@@ -91,7 +91,7 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
K(background_thresh),
(unsigned long) K(wb_stat(wb, WB_DIRTIED)),
(unsigned long) K(wb_stat(wb, WB_WRITTEN)),
- (unsigned long) K(bdi->write_bandwidth),
+ (unsigned long) K(wb->write_bandwidth),
nr_dirty,
nr_io,
nr_more_io,
@@ -376,6 +376,11 @@ void bdi_unregister(struct backing_dev_info *bdi)
}
EXPORT_SYMBOL(bdi_unregister);
+/*
+ * Initial write bandwidth: 100 MB/s
+ */
+#define INIT_BW (100 << (20 - PAGE_SHIFT))
+
static int bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
{
int i, err;
@@ -391,11 +396,22 @@ static int bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
spin_lock_init(&wb->list_lock);
INIT_DELAYED_WORK(&wb->dwork, bdi_writeback_workfn);
+ wb->bw_time_stamp = jiffies;
+ wb->balanced_dirty_ratelimit = INIT_BW;
+ wb->dirty_ratelimit = INIT_BW;
+ wb->write_bandwidth = INIT_BW;
+ wb->avg_write_bandwidth = INIT_BW;
+
+ err = fprop_local_init_percpu(&wb->completions, GFP_KERNEL);
+ if (err)
+ return err;
+
for (i = 0; i < NR_WB_STAT_ITEMS; i++) {
err = percpu_counter_init(&wb->stat[i], 0, GFP_KERNEL);
if (err) {
while (--i)
percpu_counter_destroy(&wb->stat[i]);
+ fprop_local_destroy_percpu(&wb->completions);
return err;
}
}
@@ -411,12 +427,9 @@ static void bdi_wb_exit(struct bdi_writeback *wb)
for (i = 0; i < NR_WB_STAT_ITEMS; i++)
percpu_counter_destroy(&wb->stat[i]);
-}
-/*
- * Initial write bandwidth: 100 MB/s
- */
-#define INIT_BW (100 << (20 - PAGE_SHIFT))
+ fprop_local_destroy_percpu(&wb->completions);
+}
int bdi_init(struct backing_dev_info *bdi)
{
@@ -435,22 +448,6 @@ int bdi_init(struct backing_dev_info *bdi)
if (err)
return err;
- bdi->dirty_exceeded = 0;
-
- bdi->bw_time_stamp = jiffies;
- bdi->written_stamp = 0;
-
- bdi->balanced_dirty_ratelimit = INIT_BW;
- bdi->dirty_ratelimit = INIT_BW;
- bdi->write_bandwidth = INIT_BW;
- bdi->avg_write_bandwidth = INIT_BW;
-
- err = fprop_local_init_percpu(&bdi->completions, GFP_KERNEL);
- if (err) {
- bdi_wb_exit(&bdi->wb);
- return err;
- }
-
return 0;
}
EXPORT_SYMBOL(bdi_init);
@@ -468,8 +465,6 @@ void bdi_destroy(struct backing_dev_info *bdi)
}
bdi_wb_exit(&bdi->wb);
-
- fprop_local_destroy_percpu(&bdi->completions);
}
EXPORT_SYMBOL(bdi_destroy);