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authorTejun Heo <tj@kernel.org>2015-05-23 00:13:27 +0300
committerJens Axboe <axboe@fb.com>2015-06-02 17:33:34 +0300
commit93f78d882865cb90020d0f80a9523c99cf46924c (patch)
tree6cd9c3531085c7d51fbd6ec2086142255bc2c219 /mm/backing-dev.c
parent4452226ea276e74fc3e252c88d9bb7e8f8e44bf0 (diff)
downloadlinux-93f78d882865cb90020d0f80a9523c99cf46924c.tar.xz
writeback: move backing_dev_info->bdi_stat[] 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 bdi->bdi_stat[] into wb. * enum bdi_stat_item is renamed to wb_stat_item and the prefix of all enums is changed from BDI_ to WB_. * BDI_STAT_BATCH() -> WB_STAT_BATCH() * [__]{add|inc|dec|sum}_wb_stat(bdi, ...) -> [__]{add|inc}_wb_stat(wb, ...) * bdi_stat[_error]() -> wb_stat[_error]() * bdi_writeout_inc() -> wb_writeout_inc() * stat init is moved to bdi_wb_init() and bdi_wb_exit() is added and frees stat. * 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. 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: Miklos Szeredi <miklos@szeredi.hu> Cc: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'mm/backing-dev.c')
-rw-r--r--mm/backing-dev.c60
1 files changed, 37 insertions, 23 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index b23cf0ea5912..7b1d1917b658 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -84,13 +84,13 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
"b_dirty_time: %10lu\n"
"bdi_list: %10u\n"
"state: %10lx\n",
- (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
- (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
+ (unsigned long) K(wb_stat(wb, WB_WRITEBACK)),
+ (unsigned long) K(wb_stat(wb, WB_RECLAIMABLE)),
K(bdi_thresh),
K(dirty_thresh),
K(background_thresh),
- (unsigned long) K(bdi_stat(bdi, BDI_DIRTIED)),
- (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)),
+ (unsigned long) K(wb_stat(wb, WB_DIRTIED)),
+ (unsigned long) K(wb_stat(wb, WB_WRITTEN)),
(unsigned long) K(bdi->write_bandwidth),
nr_dirty,
nr_io,
@@ -376,8 +376,10 @@ void bdi_unregister(struct backing_dev_info *bdi)
}
EXPORT_SYMBOL(bdi_unregister);
-static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
+static int bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
{
+ int i, err;
+
memset(wb, 0, sizeof(*wb));
wb->bdi = bdi;
@@ -388,6 +390,27 @@ static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
INIT_LIST_HEAD(&wb->b_dirty_time);
spin_lock_init(&wb->list_lock);
INIT_DELAYED_WORK(&wb->dwork, bdi_writeback_workfn);
+
+ 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]);
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+static void bdi_wb_exit(struct bdi_writeback *wb)
+{
+ int i;
+
+ WARN_ON(delayed_work_pending(&wb->dwork));
+
+ for (i = 0; i < NR_WB_STAT_ITEMS; i++)
+ percpu_counter_destroy(&wb->stat[i]);
}
/*
@@ -397,7 +420,7 @@ static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
int bdi_init(struct backing_dev_info *bdi)
{
- int i, err;
+ int err;
bdi->dev = NULL;
@@ -408,13 +431,9 @@ int bdi_init(struct backing_dev_info *bdi)
INIT_LIST_HEAD(&bdi->bdi_list);
INIT_LIST_HEAD(&bdi->work_list);
- bdi_wb_init(&bdi->wb, bdi);
-
- for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
- err = percpu_counter_init(&bdi->bdi_stat[i], 0, GFP_KERNEL);
- if (err)
- goto err;
- }
+ err = bdi_wb_init(&bdi->wb, bdi);
+ if (err)
+ return err;
bdi->dirty_exceeded = 0;
@@ -427,25 +446,20 @@ int bdi_init(struct backing_dev_info *bdi)
bdi->avg_write_bandwidth = INIT_BW;
err = fprop_local_init_percpu(&bdi->completions, GFP_KERNEL);
-
if (err) {
-err:
- while (i--)
- percpu_counter_destroy(&bdi->bdi_stat[i]);
+ bdi_wb_exit(&bdi->wb);
+ return err;
}
- return err;
+ return 0;
}
EXPORT_SYMBOL(bdi_init);
void bdi_destroy(struct backing_dev_info *bdi)
{
- int i;
-
bdi_wb_shutdown(bdi);
WARN_ON(!list_empty(&bdi->work_list));
- WARN_ON(delayed_work_pending(&bdi->wb.dwork));
if (bdi->dev) {
bdi_debug_unregister(bdi);
@@ -453,8 +467,8 @@ void bdi_destroy(struct backing_dev_info *bdi)
bdi->dev = NULL;
}
- for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
- percpu_counter_destroy(&bdi->bdi_stat[i]);
+ bdi_wb_exit(&bdi->wb);
+
fprop_local_destroy_percpu(&bdi->completions);
}
EXPORT_SYMBOL(bdi_destroy);