diff options
Diffstat (limited to 'include/linux/writeback.h')
| -rw-r--r-- | include/linux/writeback.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index e9d371b6053..b625073b80c 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -7,6 +7,27 @@ #include <linux/sched.h> #include <linux/fs.h> +/* + * The 1/16 region above the global dirty limit will be put to maximum pauses: + * + * (limit, limit + limit/DIRTY_MAXPAUSE_AREA) + * + * The 1/16 region above the max-pause region, dirty exceeded bdi's will be put + * to loops: + * + * (limit + limit/DIRTY_MAXPAUSE_AREA, limit + limit/DIRTY_PASSGOOD_AREA) + * + * Further beyond, all dirtier tasks will enter a loop waiting (possibly long + * time) for the dirty pages to drop, unless written enough pages. + * + * The global dirty threshold is normally equal to the global dirty limit, + * except when the system suddenly allocates a lot of anonymous memory and + * knocks down the global dirty threshold quickly, in which case the global + * dirty limit will follow down slowly to prevent livelocking all dirtier tasks. + */ +#define DIRTY_MAXPAUSE_AREA 16 +#define DIRTY_PASSGOOD_AREA 8 + struct backing_dev_info; /* |