From 93f78d882865cb90020d0f80a9523c99cf46924c Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:27 -0400 Subject: [PATCH] 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 --- fs/fs-writeback.c | 2 +- fs/fuse/file.c | 12 +++---- fs/nfs/internal.h | 2 +- fs/nfs/write.c | 3 +- include/linux/backing-dev.h | 68 +++++++++++++++++-------------------- mm/backing-dev.c | 60 +++++++++++++++++++------------- mm/page-writeback.c | 55 +++++++++++++++--------------- 7 files changed, 106 insertions(+), 96 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 983312cea245..8873ecd1578c 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -840,7 +840,7 @@ static bool over_bground_thresh(struct backing_dev_info *bdi) global_page_state(NR_UNSTABLE_NFS) > background_thresh) return true; - if (bdi_stat(bdi, BDI_RECLAIMABLE) > + if (wb_stat(&bdi->wb, WB_RECLAIMABLE) > bdi_dirty_limit(bdi, background_thresh)) return true; diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 5ef05b5c4cff..8c5e2fa68835 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1445,9 +1445,9 @@ static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req) list_del(&req->writepages_entry); for (i = 0; i < req->num_pages; i++) { - dec_bdi_stat(bdi, BDI_WRITEBACK); + dec_wb_stat(&bdi->wb, WB_WRITEBACK); dec_zone_page_state(req->pages[i], NR_WRITEBACK_TEMP); - bdi_writeout_inc(bdi); + wb_writeout_inc(&bdi->wb); } wake_up(&fi->page_waitq); } @@ -1634,7 +1634,7 @@ static int fuse_writepage_locked(struct page *page) req->end = fuse_writepage_end; req->inode = inode; - inc_bdi_stat(inode_to_bdi(inode), BDI_WRITEBACK); + inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK); inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP); spin_lock(&fc->lock); @@ -1749,9 +1749,9 @@ static bool fuse_writepage_in_flight(struct fuse_req *new_req, copy_highpage(old_req->pages[0], page); spin_unlock(&fc->lock); - dec_bdi_stat(bdi, BDI_WRITEBACK); + dec_wb_stat(&bdi->wb, WB_WRITEBACK); dec_zone_page_state(page, NR_WRITEBACK_TEMP); - bdi_writeout_inc(bdi); + wb_writeout_inc(&bdi->wb); fuse_writepage_free(fc, new_req); fuse_request_free(new_req); goto out; @@ -1848,7 +1848,7 @@ static int fuse_writepages_fill(struct page *page, req->page_descs[req->num_pages].offset = 0; req->page_descs[req->num_pages].length = PAGE_SIZE; - inc_bdi_stat(inode_to_bdi(inode), BDI_WRITEBACK); + inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK); inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP); err = 0; diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index 9e6475bc5ba2..7e3c4604bea8 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -607,7 +607,7 @@ void nfs_mark_page_unstable(struct page *page) struct inode *inode = page_file_mapping(page)->host; inc_zone_page_state(page, NR_UNSTABLE_NFS); - inc_bdi_stat(inode_to_bdi(inode), BDI_RECLAIMABLE); + inc_wb_stat(&inode_to_bdi(inode)->wb, WB_RECLAIMABLE); __mark_inode_dirty(inode, I_DIRTY_DATASYNC); } diff --git a/fs/nfs/write.c b/fs/nfs/write.c index d12a4be613a5..94c7ce01dfb1 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -853,7 +853,8 @@ static void nfs_clear_page_commit(struct page *page) { dec_zone_page_state(page, NR_UNSTABLE_NFS); - dec_bdi_stat(inode_to_bdi(page_file_mapping(page)->host), BDI_RECLAIMABLE); + dec_wb_stat(&inode_to_bdi(page_file_mapping(page)->host)->wb, + WB_RECLAIMABLE); } /* Called holding inode (/cinfo) lock */ diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index eb14f988a63e..fe7a907a4e16 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -36,15 +36,15 @@ enum wb_state { typedef int (congested_fn)(void *, int); -enum bdi_stat_item { - BDI_RECLAIMABLE, - BDI_WRITEBACK, - BDI_DIRTIED, - BDI_WRITTEN, - NR_BDI_STAT_ITEMS +enum wb_stat_item { + WB_RECLAIMABLE, + WB_WRITEBACK, + WB_DIRTIED, + WB_WRITTEN, + NR_WB_STAT_ITEMS }; -#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) +#define WB_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) struct bdi_writeback { struct backing_dev_info *bdi; /* our parent bdi */ @@ -58,6 +58,8 @@ struct bdi_writeback { struct list_head b_more_io; /* parked for more writeback */ struct list_head b_dirty_time; /* time stamps are dirty */ spinlock_t list_lock; /* protects the b_* lists */ + + struct percpu_counter stat[NR_WB_STAT_ITEMS]; }; struct backing_dev_info { @@ -69,8 +71,6 @@ struct backing_dev_info { char *name; - struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; - unsigned long bw_time_stamp; /* last time write bw is updated */ unsigned long dirtied_stamp; unsigned long written_stamp; /* pages written at bw_time_stamp */ @@ -137,78 +137,74 @@ static inline int wb_has_dirty_io(struct bdi_writeback *wb) !list_empty(&wb->b_more_io); } -static inline void __add_bdi_stat(struct backing_dev_info *bdi, - enum bdi_stat_item item, s64 amount) +static inline void __add_wb_stat(struct bdi_writeback *wb, + enum wb_stat_item item, s64 amount) { - __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH); + __percpu_counter_add(&wb->stat[item], amount, WB_STAT_BATCH); } -static inline void __inc_bdi_stat(struct backing_dev_info *bdi, - enum bdi_stat_item item) +static inline void __inc_wb_stat(struct bdi_writeback *wb, + enum wb_stat_item item) { - __add_bdi_stat(bdi, item, 1); + __add_wb_stat(wb, item, 1); } -static inline void inc_bdi_stat(struct backing_dev_info *bdi, - enum bdi_stat_item item) +static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) { unsigned long flags; local_irq_save(flags); - __inc_bdi_stat(bdi, item); + __inc_wb_stat(wb, item); local_irq_restore(flags); } -static inline void __dec_bdi_stat(struct backing_dev_info *bdi, - enum bdi_stat_item item) +static inline void __dec_wb_stat(struct bdi_writeback *wb, + enum wb_stat_item item) { - __add_bdi_stat(bdi, item, -1); + __add_wb_stat(wb, item, -1); } -static inline void dec_bdi_stat(struct backing_dev_info *bdi, - enum bdi_stat_item item) +static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) { unsigned long flags; local_irq_save(flags); - __dec_bdi_stat(bdi, item); + __dec_wb_stat(wb, item); local_irq_restore(flags); } -static inline s64 bdi_stat(struct backing_dev_info *bdi, - enum bdi_stat_item item) +static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) { - return percpu_counter_read_positive(&bdi->bdi_stat[item]); + return percpu_counter_read_positive(&wb->stat[item]); } -static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi, - enum bdi_stat_item item) +static inline s64 __wb_stat_sum(struct bdi_writeback *wb, + enum wb_stat_item item) { - return percpu_counter_sum_positive(&bdi->bdi_stat[item]); + return percpu_counter_sum_positive(&wb->stat[item]); } -static inline s64 bdi_stat_sum(struct backing_dev_info *bdi, - enum bdi_stat_item item) +static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item) { s64 sum; unsigned long flags; local_irq_save(flags); - sum = __bdi_stat_sum(bdi, item); + sum = __wb_stat_sum(wb, item); local_irq_restore(flags); return sum; } -extern void bdi_writeout_inc(struct backing_dev_info *bdi); +extern void wb_writeout_inc(struct bdi_writeback *wb); /* * maximal error of a stat counter. */ -static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi) +static inline unsigned long wb_stat_error(struct bdi_writeback *wb) { #ifdef CONFIG_SMP - return nr_cpu_ids * BDI_STAT_BATCH; + return nr_cpu_ids * WB_STAT_BATCH; #else return 1; #endif 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); 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,