From ec8a6f2643923ee5b74d24fa8d134240379f436b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:41 -0400 Subject: [PATCH] writeback: make congestion functions per bdi_writeback Currently, all congestion functions take bdi (backing_dev_info) and always operate on the root wb (bdi->wb) and the congestion state from the block layer is propagated only for the root blkcg. This patch introduces {set|clear}_wb_congested() and wb_congested() which take a bdi_writeback_congested and bdi_writeback respectively. The bdi counteparts are now wrappers invoking the wb based functions on @bdi->wb. While converting clear_bdi_congested() to clear_wb_congested(), the local variable declaration order between @wqh and @bit is swapped for cosmetic reason. This patch just adds the new wb based functions. The following patches will apply them. v2: Updated for bdi_writeback_congested. Signed-off-by: Tejun Heo Reviewed-by: Jan Kara Cc: Jens Axboe Signed-off-by: Jens Axboe --- include/linux/backing-dev-defs.h | 14 ++++++++-- include/linux/backing-dev.h | 45 ++++++++++++++++++-------------- mm/backing-dev.c | 22 ++++++++-------- 3 files changed, 49 insertions(+), 32 deletions(-) diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index a1e9c407a59a..eb386766b5f3 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -163,7 +163,17 @@ enum { BLK_RW_SYNC = 1, }; -void clear_bdi_congested(struct backing_dev_info *bdi, int sync); -void set_bdi_congested(struct backing_dev_info *bdi, int sync); +void clear_wb_congested(struct bdi_writeback_congested *congested, int sync); +void set_wb_congested(struct bdi_writeback_congested *congested, int sync); + +static inline void clear_bdi_congested(struct backing_dev_info *bdi, int sync) +{ + clear_wb_congested(bdi->wb.congested, sync); +} + +static inline void set_bdi_congested(struct backing_dev_info *bdi, int sync) +{ + set_wb_congested(bdi->wb.congested, sync); +} #endif /* __LINUX_BACKING_DEV_DEFS_H */ diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 8ae59df2e3d1..2c498a2a8268 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -167,27 +167,13 @@ static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) return sb->s_bdi; } -static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) +static inline int wb_congested(struct bdi_writeback *wb, int cong_bits) { + struct backing_dev_info *bdi = wb->bdi; + if (bdi->congested_fn) - return bdi->congested_fn(bdi->congested_data, bdi_bits); - return (bdi->wb.congested->state & bdi_bits); -} - -static inline int bdi_read_congested(struct backing_dev_info *bdi) -{ - return bdi_congested(bdi, 1 << WB_sync_congested); -} - -static inline int bdi_write_congested(struct backing_dev_info *bdi) -{ - return bdi_congested(bdi, 1 << WB_async_congested); -} - -static inline int bdi_rw_congested(struct backing_dev_info *bdi) -{ - return bdi_congested(bdi, (1 << WB_sync_congested) | - (1 << WB_async_congested)); + return bdi->congested_fn(bdi->congested_data, cong_bits); + return wb->congested->state & cong_bits; } long congestion_wait(int sync, long timeout); @@ -454,4 +440,25 @@ static inline void wb_blkcg_offline(struct blkcg *blkcg) #endif /* CONFIG_CGROUP_WRITEBACK */ +static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits) +{ + return wb_congested(&bdi->wb, cong_bits); +} + +static inline int bdi_read_congested(struct backing_dev_info *bdi) +{ + return bdi_congested(bdi, 1 << WB_sync_congested); +} + +static inline int bdi_write_congested(struct backing_dev_info *bdi) +{ + return bdi_congested(bdi, 1 << WB_async_congested); +} + +static inline int bdi_rw_congested(struct backing_dev_info *bdi) +{ + return bdi_congested(bdi, (1 << WB_sync_congested) | + (1 << WB_async_congested)); +} + #endif /* _LINUX_BACKING_DEV_H */ diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 4c9386c98ec1..5029c4ad2f36 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -896,31 +896,31 @@ static wait_queue_head_t congestion_wqh[2] = { __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) }; -static atomic_t nr_bdi_congested[2]; +static atomic_t nr_wb_congested[2]; -void clear_bdi_congested(struct backing_dev_info *bdi, int sync) +void clear_wb_congested(struct bdi_writeback_congested *congested, int sync) { - enum wb_state bit; wait_queue_head_t *wqh = &congestion_wqh[sync]; + enum wb_state bit; bit = sync ? WB_sync_congested : WB_async_congested; - if (test_and_clear_bit(bit, &bdi->wb.congested->state)) - atomic_dec(&nr_bdi_congested[sync]); + if (test_and_clear_bit(bit, &congested->state)) + atomic_dec(&nr_wb_congested[sync]); smp_mb__after_atomic(); if (waitqueue_active(wqh)) wake_up(wqh); } -EXPORT_SYMBOL(clear_bdi_congested); +EXPORT_SYMBOL(clear_wb_congested); -void set_bdi_congested(struct backing_dev_info *bdi, int sync) +void set_wb_congested(struct bdi_writeback_congested *congested, int sync) { enum wb_state bit; bit = sync ? WB_sync_congested : WB_async_congested; - if (!test_and_set_bit(bit, &bdi->wb.congested->state)) - atomic_inc(&nr_bdi_congested[sync]); + if (!test_and_set_bit(bit, &congested->state)) + atomic_inc(&nr_wb_congested[sync]); } -EXPORT_SYMBOL(set_bdi_congested); +EXPORT_SYMBOL(set_wb_congested); /** * congestion_wait - wait for a backing_dev to become uncongested @@ -979,7 +979,7 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout) * encountered in the current zone, yield if necessary instead * of sleeping on the congestion queue */ - if (atomic_read(&nr_bdi_congested[sync]) == 0 || + if (atomic_read(&nr_wb_congested[sync]) == 0 || !test_bit(ZONE_CONGESTED, &zone->flags)) { cond_resched();