mm: add bdi_get_max_bytes() function

This adds a function to return the specified value for max_bytes. It
converts the stored max_ratio of the bdi to the corresponding bytes
value. It introduces the bdi_get_bytes helper function to do the
conversion. This is an approximation as it is based on the value that is
returned by global_dirty_limits(), which can change. The helper function
will also be used by the min_bytes bdi knob.

Link: https://lkml.kernel.org/r/20221119005215.3052436-6-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Cc: Chris Mason <clm@meta.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Stefan Roesch
2022-11-18 16:52:00 -08:00
committed by Andrew Morton
parent ae82291e9c
commit 00df7d5126
2 changed files with 18 additions and 0 deletions

View File

@@ -105,6 +105,7 @@ static inline unsigned long wb_stat_error(void)
/* BDI ratio is expressed as part per 1000000 for finer granularity. */
#define BDI_RATIO_SCALE 10000
u64 bdi_get_max_bytes(struct backing_dev_info *bdi);
int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit);