linux-master/mm/page-writeback.c

259  * Because the user is allowed to specify the dirty limit globally as
260  * absolute number of bytes, calculating the per-zone dirty limit can
261  * require translating the configured limit into a percentage of
482  * dirty limit, %false if the limit is exceeded.
486 	unsigned long limit = node_dirty_limit(pgdat);
492 	return nr_pages <= limit;
846  * threshold as a hard limit when sleeping max_pause per page is not enough
857  * The wb's share of dirty limit will be adapting to its throughput and
860  * Return: @wb's dirty limit in pages. For dirty throttling limit, the term
920  *                           limit - setpoint
926  * (3) f(limit)    = 0   => the hard limit
933 					  unsigned long limit)
939 		      (limit - setpoint) | 1);
987  *           freerun^          setpoint^                 limit^   dirty pages
1028 	unsigned long limit = hard_dirty_limit(dtc_dom(dtc), dtc->thresh);
1034 	long long pos_ratio;		/* for scaling up/down the rate limit */
1039 	if (unlikely(dtc->dirty >= limit))
1047 	setpoint = (freerun + limit) / 2;
1048 	pos_ratio = pos_ratio_polynom(setpoint, dtc->dirty, limit);
1103 		 * wb's) while given strictlimit wb is below limit.
1161 	wb_thresh = max(wb_thresh, (limit - dtc->dirty) / 8);
1256 	unsigned long limit = dom->dirty_limit;
1261 	if (limit < thresh) {
1262 		limit = thresh;
1272 	if (limit > thresh) {
1273 		limit -= (limit - thresh) >> 5;
1278 	dom->dirty_limit = limit;
1313 	unsigned long limit = hard_dirty_limit(dtc_dom(dtc), dtc->thresh);
1314 	unsigned long setpoint = (freerun + limit) / 2;
1341 	 * formula will yield the balanced rate limit (write_bw / N).
1382 	 * limit the step size.
1403 	 * |task_ratelimit - dirty_ratelimit| is used to limit the step size
1606 	 * 2) limit the target pause time to max_pause/2, so that the normal
2080  * Once we're over the dirty memory limit we decrease the ratelimiting
2081  * by a lot, to prevent individual processes from overshooting the limit