diff options
| -rw-r--r-- | Documentation/sysctl/vm.txt | 7 | ||||
| -rw-r--r-- | mm/page-writeback.c | 5 |
2 files changed, 11 insertions, 1 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 9baf66a9ef4e..30fd16b14196 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -157,6 +157,10 @@ Note: the minimum value allowed for dirty_bytes is two pages (in bytes); any value lower than this limit will be ignored and the old configuration will be retained. +Note: the value of dirty_bytes also must be set greater than +dirty_background_bytes or the amount of memory corresponding to +dirty_background_ratio. + ============================================================== dirty_expire_centisecs @@ -176,6 +180,9 @@ generating disk writes will itself start writing out dirty data. The total available memory is not equal to total system memory. +Note: dirty_ratio must be set greater than dirty_background_ratio or +ratio corresponding to dirty_background_bytes. + ============================================================== dirty_writeback_centisecs diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 76a43c17761b..768fe4e37e6a 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -433,8 +433,11 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc) else bg_thresh = (bg_ratio * available_memory) / PAGE_SIZE; - if (bg_thresh >= thresh) + if (unlikely(bg_thresh >= thresh)) { + pr_warn("vm direct limit must be set greater than background limit.\n"); bg_thresh = thresh / 2; + } + tsk = current; if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) { bg_thresh += bg_thresh / 4 + global_wb_domain.dirty_limit / 32; |