From 93f78d882865cb90020d0f80a9523c99cf46924c Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:27 -0400 Subject: 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 Reviewed-by: Jan Kara Cc: Jens Axboe Cc: Wu Fengguang Cc: Miklos Szeredi Cc: Trond Myklebust Signed-off-by: Jens Axboe --- mm/page-writeback.c | 55 ++++++++++++++++++++++++++--------------------------- 1 file changed, 27 insertions(+), 28 deletions(-) (limited to 'mm/page-writeback.c') diff --git a/mm/page-writeback.c b/mm/page-writeback.c index bdeecad00489..dc673a035413 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -396,11 +396,11 @@ static unsigned long wp_next_time(unsigned long cur_time) * Increment the BDI's writeout completion count and the global writeout * completion count. Called from test_clear_page_writeback(). */ -static inline void __bdi_writeout_inc(struct backing_dev_info *bdi) +static inline void __wb_writeout_inc(struct bdi_writeback *wb) { - __inc_bdi_stat(bdi, BDI_WRITTEN); - __fprop_inc_percpu_max(&writeout_completions, &bdi->completions, - bdi->max_prop_frac); + __inc_wb_stat(wb, WB_WRITTEN); + __fprop_inc_percpu_max(&writeout_completions, &wb->bdi->completions, + wb->bdi->max_prop_frac); /* First event after period switching was turned off? */ if (!unlikely(writeout_period_time)) { /* @@ -414,15 +414,15 @@ static inline void __bdi_writeout_inc(struct backing_dev_info *bdi) } } -void bdi_writeout_inc(struct backing_dev_info *bdi) +void wb_writeout_inc(struct bdi_writeback *wb) { unsigned long flags; local_irq_save(flags); - __bdi_writeout_inc(bdi); + __wb_writeout_inc(wb); local_irq_restore(flags); } -EXPORT_SYMBOL_GPL(bdi_writeout_inc); +EXPORT_SYMBOL_GPL(wb_writeout_inc); /* * Obtain an accurate fraction of the BDI's portion. @@ -1130,8 +1130,8 @@ void __bdi_update_bandwidth(struct backing_dev_info *bdi, if (elapsed < BANDWIDTH_INTERVAL) return; - dirtied = percpu_counter_read(&bdi->bdi_stat[BDI_DIRTIED]); - written = percpu_counter_read(&bdi->bdi_stat[BDI_WRITTEN]); + dirtied = percpu_counter_read(&bdi->wb.stat[WB_DIRTIED]); + written = percpu_counter_read(&bdi->wb.stat[WB_WRITTEN]); /* * Skip quiet periods when disk bandwidth is under-utilized. @@ -1288,7 +1288,8 @@ static inline void bdi_dirty_limits(struct backing_dev_info *bdi, unsigned long *bdi_thresh, unsigned long *bdi_bg_thresh) { - unsigned long bdi_reclaimable; + struct bdi_writeback *wb = &bdi->wb; + unsigned long wb_reclaimable; /* * bdi_thresh is not treated as some limiting factor as @@ -1320,14 +1321,12 @@ static inline void bdi_dirty_limits(struct backing_dev_info *bdi, * actually dirty; with m+n sitting in the percpu * deltas. */ - if (*bdi_thresh < 2 * bdi_stat_error(bdi)) { - bdi_reclaimable = bdi_stat_sum(bdi, BDI_RECLAIMABLE); - *bdi_dirty = bdi_reclaimable + - bdi_stat_sum(bdi, BDI_WRITEBACK); + if (*bdi_thresh < 2 * wb_stat_error(wb)) { + wb_reclaimable = wb_stat_sum(wb, WB_RECLAIMABLE); + *bdi_dirty = wb_reclaimable + wb_stat_sum(wb, WB_WRITEBACK); } else { - bdi_reclaimable = bdi_stat(bdi, BDI_RECLAIMABLE); - *bdi_dirty = bdi_reclaimable + - bdi_stat(bdi, BDI_WRITEBACK); + wb_reclaimable = wb_stat(wb, WB_RECLAIMABLE); + *bdi_dirty = wb_reclaimable + wb_stat(wb, WB_WRITEBACK); } } @@ -1514,9 +1513,9 @@ pause: * In theory 1 page is enough to keep the comsumer-producer * pipe going: the flusher cleans 1 page => the task dirties 1 * more page. However bdi_dirty has accounting errors. So use - * the larger and more IO friendly bdi_stat_error. + * the larger and more IO friendly wb_stat_error. */ - if (bdi_dirty <= bdi_stat_error(bdi)) + if (bdi_dirty <= wb_stat_error(&bdi->wb)) break; if (fatal_signal_pending(current)) @@ -2106,8 +2105,8 @@ void account_page_dirtied(struct page *page, struct address_space *mapping, mem_cgroup_inc_page_stat(memcg, MEM_CGROUP_STAT_DIRTY); __inc_zone_page_state(page, NR_FILE_DIRTY); __inc_zone_page_state(page, NR_DIRTIED); - __inc_bdi_stat(bdi, BDI_RECLAIMABLE); - __inc_bdi_stat(bdi, BDI_DIRTIED); + __inc_wb_stat(&bdi->wb, WB_RECLAIMABLE); + __inc_wb_stat(&bdi->wb, WB_DIRTIED); task_io_account_write(PAGE_CACHE_SIZE); current->nr_dirtied++; this_cpu_inc(bdp_ratelimits); @@ -2126,7 +2125,7 @@ void account_page_cleaned(struct page *page, struct address_space *mapping, if (mapping_cap_account_dirty(mapping)) { mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_DIRTY); dec_zone_page_state(page, NR_FILE_DIRTY); - dec_bdi_stat(inode_to_bdi(mapping->host), BDI_RECLAIMABLE); + dec_wb_stat(&inode_to_bdi(mapping->host)->wb, WB_RECLAIMABLE); task_io_account_cancelled_write(PAGE_CACHE_SIZE); } } @@ -2190,7 +2189,7 @@ void account_page_redirty(struct page *page) if (mapping && mapping_cap_account_dirty(mapping)) { current->nr_dirtied--; dec_zone_page_state(page, NR_DIRTIED); - dec_bdi_stat(inode_to_bdi(mapping->host), BDI_DIRTIED); + dec_wb_stat(&inode_to_bdi(mapping->host)->wb, WB_DIRTIED); } } EXPORT_SYMBOL(account_page_redirty); @@ -2369,8 +2368,8 @@ int clear_page_dirty_for_io(struct page *page) if (TestClearPageDirty(page)) { mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_DIRTY); dec_zone_page_state(page, NR_FILE_DIRTY); - dec_bdi_stat(inode_to_bdi(mapping->host), - BDI_RECLAIMABLE); + dec_wb_stat(&inode_to_bdi(mapping->host)->wb, + WB_RECLAIMABLE); ret = 1; } mem_cgroup_end_page_stat(memcg); @@ -2398,8 +2397,8 @@ int test_clear_page_writeback(struct page *page) page_index(page), PAGECACHE_TAG_WRITEBACK); if (bdi_cap_account_writeback(bdi)) { - __dec_bdi_stat(bdi, BDI_WRITEBACK); - __bdi_writeout_inc(bdi); + __dec_wb_stat(&bdi->wb, WB_WRITEBACK); + __wb_writeout_inc(&bdi->wb); } } spin_unlock_irqrestore(&mapping->tree_lock, flags); @@ -2433,7 +2432,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write) page_index(page), PAGECACHE_TAG_WRITEBACK); if (bdi_cap_account_writeback(bdi)) - __inc_bdi_stat(bdi, BDI_WRITEBACK); + __inc_wb_stat(&bdi->wb, WB_WRITEBACK); } if (!PageDirty(page)) radix_tree_tag_clear(&mapping->page_tree, -- cgit v1.2.3