1 files changed, 30 insertions, 21 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 11ff8f758631..e2481949494c 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -296,11 +296,15 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
 #ifdef CONFIG_HIGHMEM
 	int node;
 	unsigned long x = 0;
+	int i;
 
 	for_each_node_state(node, N_HIGH_MEMORY) {
-		struct zone *z = &NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
+		for (i = 0; i < MAX_NR_ZONES; i++) {
+			struct zone *z = &NODE_DATA(node)->node_zones[i];
 
-		x += zone_dirtyable_memory(z);
+			if (is_highmem(z))
+				x += zone_dirtyable_memory(z);
+		}
 	}
 	/*
 	 * Unreclaimable memory (kernel memory or anonymous memory
@@ -369,8 +373,9 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc)
 	struct dirty_throttle_control *gdtc = mdtc_gdtc(dtc);
 	unsigned long bytes = vm_dirty_bytes;
 	unsigned long bg_bytes = dirty_background_bytes;
-	unsigned long ratio = vm_dirty_ratio;
-	unsigned long bg_ratio = dirty_background_ratio;
+	/* convert ratios to per-PAGE_SIZE for higher precision */
+	unsigned long ratio = (vm_dirty_ratio * PAGE_SIZE) / 100;
+	unsigned long bg_ratio = (dirty_background_ratio * PAGE_SIZE) / 100;
 	unsigned long thresh;
 	unsigned long bg_thresh;
 	struct task_struct *tsk;
@@ -382,33 +387,35 @@ static void domain_dirty_limits(struct dirty_throttle_control *dtc)
 		/*
 		 * The byte settings can't be applied directly to memcg
 		 * domains.  Convert them to ratios by scaling against
-		 * globally available memory.
+		 * globally available memory.  As the ratios are in
+		 * per-PAGE_SIZE, they can be obtained by dividing bytes by
+		 * number of pages.
 		 */
 		if (bytes)
-			ratio = min(DIV_ROUND_UP(bytes, PAGE_SIZE) * 100 /
-				    global_avail, 100UL);
+			ratio = min(DIV_ROUND_UP(bytes, global_avail),
+				    PAGE_SIZE);
 		if (bg_bytes)
-			bg_ratio = min(DIV_ROUND_UP(bg_bytes, PAGE_SIZE) * 100 /
-				       global_avail, 100UL);
+			bg_ratio = min(DIV_ROUND_UP(bg_bytes, global_avail),
+				       PAGE_SIZE);
 		bytes = bg_bytes = 0;
 	}
 
 	if (bytes)
 		thresh = DIV_ROUND_UP(bytes, PAGE_SIZE);
 	else
-		thresh = (ratio * available_memory) / 100;
+		thresh = (ratio * available_memory) / PAGE_SIZE;
 
 	if (bg_bytes)
 		bg_thresh = DIV_ROUND_UP(bg_bytes, PAGE_SIZE);
 	else
-		bg_thresh = (bg_ratio * available_memory) / 100;
+		bg_thresh = (bg_ratio * available_memory) / PAGE_SIZE;
 
 	if (bg_thresh >= thresh)
 		bg_thresh = thresh / 2;
 	tsk = current;
 	if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) {
-		bg_thresh += bg_thresh / 4;
-		thresh += thresh / 4;
+		bg_thresh += bg_thresh / 4 + global_wb_domain.dirty_limit / 32;
+		thresh += thresh / 4 + global_wb_domain.dirty_limit / 32;
 	}
 	dtc->thresh = thresh;
 	dtc->bg_thresh = bg_thresh;
@@ -1910,7 +1917,8 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
 	if (gdtc->dirty > gdtc->bg_thresh)
 		return true;
 
-	if (wb_stat(wb, WB_RECLAIMABLE) > __wb_calc_thresh(gdtc))
+	if (wb_stat(wb, WB_RECLAIMABLE) >
+	    wb_calc_thresh(gdtc->wb, gdtc->bg_thresh))
 		return true;
 
 	if (mdtc) {
@@ -1924,7 +1932,8 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
 		if (mdtc->dirty > mdtc->bg_thresh)
 			return true;
 
-		if (wb_stat(wb, WB_RECLAIMABLE) > __wb_calc_thresh(mdtc))
+		if (wb_stat(wb, WB_RECLAIMABLE) >
+		    wb_calc_thresh(mdtc->wb, mdtc->bg_thresh))
 			return true;
 	}
 
@@ -2176,8 +2185,8 @@ int write_cache_pages(struct address_space *mapping,
 			cycled = 0;
 		end = -1;
 	} else {
-		index = wbc->range_start >> PAGE_CACHE_SHIFT;
-		end = wbc->range_end >> PAGE_CACHE_SHIFT;
+		index = wbc->range_start >> PAGE_SHIFT;
+		end = wbc->range_end >> PAGE_SHIFT;
 		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 			range_whole = 1;
 		cycled = 1; /* ignore range_cyclic tests */
@@ -2382,14 +2391,14 @@ int write_one_page(struct page *page, int wait)
 		wait_on_page_writeback(page);
 
 	if (clear_page_dirty_for_io(page)) {
-		page_cache_get(page);
+		get_page(page);
 		ret = mapping->a_ops->writepage(page, &wbc);
 		if (ret == 0 && wait) {
 			wait_on_page_writeback(page);
 			if (PageError(page))
 				ret = -EIO;
 		}
-		page_cache_release(page);
+		put_page(page);
 	} else {
 		unlock_page(page);
 	}
@@ -2431,7 +2440,7 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 		__inc_zone_page_state(page, NR_DIRTIED);
 		__inc_wb_stat(wb, WB_RECLAIMABLE);
 		__inc_wb_stat(wb, WB_DIRTIED);
-		task_io_account_write(PAGE_CACHE_SIZE);
+		task_io_account_write(PAGE_SIZE);
 		current->nr_dirtied++;
 		this_cpu_inc(bdp_ratelimits);
 	}
@@ -2450,7 +2459,7 @@ void account_page_cleaned(struct page *page, struct address_space *mapping,
 		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY);
 		dec_zone_page_state(page, NR_FILE_DIRTY);
 		dec_wb_stat(wb, WB_RECLAIMABLE);
-		task_io_account_cancelled_write(PAGE_CACHE_SIZE);
+		task_io_account_cancelled_write(PAGE_SIZE);
 	}
 }