diff options
| -rw-r--r-- | mm/page-writeback.c | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index f9d9f5476d58..1d781803e629 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -281,12 +281,13 @@ static inline void task_dirties_fraction(struct task_struct *tsk, * effectively curb the growth of dirty pages. Light dirtiers with high enough * dirty threshold may never get throttled. */ +#define TASK_LIMIT_FRACTION 8 static unsigned long task_dirty_limit(struct task_struct *tsk, unsigned long bdi_dirty) { long numerator, denominator; unsigned long dirty = bdi_dirty; - u64 inv = dirty >> 3; + u64 inv = dirty / TASK_LIMIT_FRACTION; task_dirties_fraction(tsk, &numerator, &denominator); inv *= numerator; @@ -297,6 +298,12 @@ static unsigned long task_dirty_limit(struct task_struct *tsk, return max(dirty, bdi_dirty/2); } +/* Minimum limit for any task */ +static unsigned long task_min_dirty_limit(unsigned long bdi_dirty) +{ + return bdi_dirty - bdi_dirty / TASK_LIMIT_FRACTION; +} + /* * */ @@ -651,9 +658,12 @@ static void balance_dirty_pages(struct address_space *mapping, unsigned long background_thresh; unsigned long dirty_thresh; unsigned long bdi_thresh; + unsigned long task_bdi_thresh; + unsigned long min_task_bdi_thresh; unsigned long pages_written = 0; unsigned long pause = 1; bool dirty_exceeded = false; + bool clear_dirty_exceeded = true; struct backing_dev_info *bdi = mapping->backing_dev_info; unsigned long start_time = jiffies; @@ -673,7 +683,8 @@ static void balance_dirty_pages(struct address_space *mapping, break; bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh); - bdi_thresh = task_dirty_limit(current, bdi_thresh); + min_task_bdi_thresh = task_min_dirty_limit(bdi_thresh); + task_bdi_thresh = task_dirty_limit(current, bdi_thresh); /* * In order to avoid the stacked BDI deadlock we need @@ -685,7 +696,7 @@ static void balance_dirty_pages(struct address_space *mapping, * actually dirty; with m+n sitting in the percpu * deltas. */ - if (bdi_thresh < 2*bdi_stat_error(bdi)) { + if (task_bdi_thresh < 2 * bdi_stat_error(bdi)) { bdi_nr_reclaimable = bdi_stat_sum(bdi, BDI_RECLAIMABLE); bdi_dirty = bdi_nr_reclaimable + bdi_stat_sum(bdi, BDI_WRITEBACK); @@ -701,8 +712,10 @@ static void balance_dirty_pages(struct address_space *mapping, * bdi or process from holding back light ones; The latter is * the last resort safeguard. */ - dirty_exceeded = (bdi_dirty > bdi_thresh) || + dirty_exceeded = (bdi_dirty > task_bdi_thresh) || (nr_dirty > dirty_thresh); + clear_dirty_exceeded = (bdi_dirty <= min_task_bdi_thresh) && + (nr_dirty <= dirty_thresh); if (!dirty_exceeded) break; @@ -723,7 +736,7 @@ static void balance_dirty_pages(struct address_space *mapping, * up. */ trace_balance_dirty_start(bdi); - if (bdi_nr_reclaimable > bdi_thresh) { + if (bdi_nr_reclaimable > task_bdi_thresh) { pages_written += writeback_inodes_wb(&bdi->wb, write_chunk); trace_balance_dirty_written(bdi, pages_written); @@ -766,7 +779,8 @@ static void balance_dirty_pages(struct address_space *mapping, pause = HZ / 10; } - if (!dirty_exceeded && bdi->dirty_exceeded) + /* Clear dirty_exceeded flag only when no task can exceed the limit */ + if (clear_dirty_exceeded && bdi->dirty_exceeded) bdi->dirty_exceeded = 0; if (writeback_in_progress(bdi)) |