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Commit e9770b34 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
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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: default avatarTejun 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: default avatarJens Axboe <axboe@fb.com>
parent daddfa3c

mm/page-writeback.c

+4 −2
Original line number Diff line number Diff line
@@ -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;