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>
This commit is contained in:
Tejun Heo 2015-05-22 18:23:27 -04:00 committed by Jens Axboe
parent daddfa3cb3
commit e9770b3487
1 changed files with 4 additions and 2 deletions

View File

@ -127,6 +127,7 @@ struct wb_domain global_wb_domain;
/* 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 @@ struct dirty_throttle_control {
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 @@ static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc)
/*
* 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;