android/android_kernel_asus_sm8350
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writeback: make __wb_calc_thresh() take dirty_throttle_control

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wb_calc_thresh() calculates wb_thresh by scaling thresh according to
the wb's portion in the system-wide write bandwidth.  cgroup writeback
support would need to calculate wb_thresh against memcg domain too.
This patch renames wb_calc_thresh() to __wb_calc_thresh() and makes it
take dirty_throttle_control so that the function can later be updated
to calculate against different domains according to
dirty_throttle_control.

wb_calc_thresh() is now a thin wrapper around __wb_calc_thresh().

v2: The original version was incorrectly scaling dtc->dirty instead of
    dtc->thresh.  This was due to the extremely confusing function and
    variable names.  Added a rename patch and fixed this one.

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 18:23:25 -04:00 committed by Jens Axboe
parent 970fb01ad3
commit b1cbc6d40c
1 changed files with 14 additions and 7 deletions
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21
mm/page-writeback.c
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@ -557,9 +557,8 @@ static unsigned long hard_dirty_limit(unsigned long thresh)
}
/**
* wb_calc_thresh - @wb's share of dirty throttling threshold
* @wb: bdi_writeback to query
* @dirty: global dirty limit in pages
* __wb_calc_thresh - @wb's share of dirty throttling threshold
* @dtc: dirty_throttle_context of interest
*
* Returns @wb's dirty limit in pages. The term "dirty" in the context of
* dirty balancing includes all PG_dirty, PG_writeback and NFS unstable pages.
@ -578,9 +577,10 @@ static unsigned long hard_dirty_limit(unsigned long thresh)
* The wb's share of dirty limit will be adapting to its throughput and
* bounded by the bdi->min_ratio and/or bdi->max_ratio parameters, if set.
*/
unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh)
static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc)
{
struct wb_domain *dom = &global_wb_domain;
unsigned long thresh = dtc->thresh;
u64 wb_thresh;
long numerator, denominator;
unsigned long wb_min_ratio, wb_max_ratio;
@ -588,14 +588,14 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh)
/*
* Calculate this BDI's share of the thresh ratio.
*/
fprop_fraction_percpu(&dom->completions, &wb->completions,
fprop_fraction_percpu(&dom->completions, &dtc->wb->completions,
&numerator, &denominator);
wb_thresh = (thresh * (100 - bdi_min_ratio)) / 100;
wb_thresh *= numerator;
do_div(wb_thresh, denominator);
wb_min_max_ratio(wb, &wb_min_ratio, &wb_max_ratio);
wb_min_max_ratio(dtc->wb, &wb_min_ratio, &wb_max_ratio);
wb_thresh += (thresh * wb_min_ratio) / 100;
if (wb_thresh > (thresh * wb_max_ratio) / 100)
@ -604,6 +604,13 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh)
return wb_thresh;
}
unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh)
{
struct dirty_throttle_control gdtc = { GDTC_INIT(wb),
.thresh = thresh };
return __wb_calc_thresh(&gdtc);
}
/*
* setpoint - dirty 3
* f(dirty) := 1.0 + (----------------)
@ -1323,7 +1330,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
* wb_position_ratio() will let the dirtier task progress
* at some rate <= (write_bw / 2) for bringing down wb_dirty.
*/
dtc->wb_thresh = wb_calc_thresh(dtc->wb, dtc->thresh);
dtc->wb_thresh = __wb_calc_thresh(dtc);
dtc->wb_bg_thresh = dtc->thresh ?
div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;