writeback: add dirty_throttle_control->wb_completions
wb->completions measures the wb's proportional write bandwidth in
global_wb_domain and thus naturally tied to the wb_domain. This patch
adds dirty_throttle_control->wb_completions which is initialized to
wb->completions by GDTC_INIT() and updates __wb_dirty_limits() to use
it instead of dereferencing wb->completions directly.
This will allow dirty_throttle_control to represent different
wb_domains and the matching wb completions.
This patch doesn't introduce any behavioral changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index fcebae7..5b439fc 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -127,6 +127,7 @@
/* consolidated parameters for balance_dirty_pages() and its subroutines */
struct dirty_throttle_control {
struct bdi_writeback *wb;
+ struct fprop_local_percpu *wb_completions;
unsigned long dirty; /* file_dirty + write + nfs */
unsigned long thresh; /* dirty threshold */
@@ -139,7 +140,8 @@
unsigned long pos_ratio;
};
-#define GDTC_INIT(__wb) .wb = (__wb)
+#define GDTC_INIT(__wb) .wb = (__wb), \
+ .wb_completions = &(__wb)->completions
/*
* Length of period for aging writeout fractions of bdis. This is an
@@ -590,7 +592,7 @@
/*
* Calculate this BDI's share of the thresh ratio.
*/
- fprop_fraction_percpu(&dom->completions, &dtc->wb->completions,
+ fprop_fraction_percpu(&dom->completions, dtc->wb_completions,
&numerator, &denominator);
wb_thresh = (thresh * (100 - bdi_min_ratio)) / 100;
