writeback: add dirty_throttle_control->wb_completions (e9770b34) · Commits · 戴 / test

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>

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;

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