From a88a341a73be4ef035ca26170c849f002797da27 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:28 -0400 Subject: 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 Reviewed-by: Jan Kara Cc: Jens Axboe Cc: Wu Fengguang Cc: Jaegeuk Kim Cc: Steven Whitehouse Signed-off-by: Jens Axboe --- mm/backing-dev.c | 45 ++++++++++++++++++++------------------------- 1 file changed, 20 insertions(+), 25 deletions(-) (limited to 'mm/backing-dev.c') 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); -- cgit v1.2.1