X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=mm%2Freadahead.c;h=a5e6906a01e03073ff399da20f75821efb47e2dc;hb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;hp=7073392b3357784a514fe972a20e170ed85ee954;hpb=a2c21200f1c81b08cb55e417b68150bba439b646;p=linux-2.6.git

diff --git a/mm/readahead.c b/mm/readahead.c
index 7073392b3..a5e6906a0 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -28,16 +28,15 @@ struct backing_dev_info default_backing_dev_info = {
 EXPORT_SYMBOL_GPL(default_backing_dev_info);
 
 /*
- * Initialise a struct file's readahead state
+ * Initialise a struct file's readahead state.  Assumes that the caller has
+ * memset *ra to zero.
  */
 void
 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping)
 {
-	memset(ra, 0, sizeof(*ra));
 	ra->ra_pages = mapping->backing_dev_info->ra_pages;
 	ra->average = ra->ra_pages / 2;
 }
-EXPORT_SYMBOL(file_ra_state_init);
 
 /*
  * Return max readahead size for this inode in number-of-pages.
@@ -384,25 +383,10 @@ page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra,
 		first_access=1;
 		ra->next_size = max / 2;
 		ra->prev_page = offset;
-		ra->serial_cnt++;
+		ra->currnt_wnd_hit++;
 		goto do_io;
 	}
 
-	if (offset == ra->prev_page + 1) {
-		if (ra->serial_cnt <= (max * 2))
-			ra->serial_cnt++;
-	} else {
-		/*
-		 * to avoid rounding errors, ensure that 'average'
-		 * tends towards the value of ra->serial_cnt.
-		 */
-		average = ra->average;
-		if (average < ra->serial_cnt) {
-			average++;
-		}
-		ra->average = (average + ra->serial_cnt) / 2;
-		ra->serial_cnt = 1;
-	}
 	ra->prev_page = offset;
 
 	if (offset >= ra->start && offset <= (ra->start + ra->size)) {
@@ -411,12 +395,22 @@ page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra,
 		 * page beyond the end.  Expand the next readahead size.
 		 */
 		ra->next_size += 2;
+
+		if (ra->currnt_wnd_hit <= (max * 2))
+			ra->currnt_wnd_hit++;
 	} else {
 		/*
 		 * A miss - lseek, pagefault, pread, etc.  Shrink the readahead
 		 * window.
 		 */
 		ra->next_size -= 2;
+
+		average = ra->average;
+		if (average < ra->currnt_wnd_hit) {
+			average++;
+		}
+		ra->average = (average + ra->currnt_wnd_hit) / 2;
+		ra->currnt_wnd_hit = 1;
 	}
 
 	if ((long)ra->next_size > (long)max)
@@ -469,8 +463,8 @@ do_io:
 			  * current window.
 			  */
 			average = ra->average;
-			if (ra->serial_cnt > average)
-				average = (ra->serial_cnt + ra->average + 1) / 2;
+			if (ra->currnt_wnd_hit > average)
+				average = (ra->currnt_wnd_hit + ra->average + 1) / 2;
 
 			ra->next_size = min(average , (unsigned long)max);
 		}
@@ -505,8 +499,8 @@ do_io:
 			 * random. Hence don't bother to readahead.
 			 */
 			average = ra->average;
-			if (ra->serial_cnt > average)
-				average = (ra->serial_cnt + ra->average + 1) / 2;
+			if (ra->currnt_wnd_hit > average)
+				average = (ra->currnt_wnd_hit + ra->average + 1) / 2;
 
 			if (average > max) {
 				ra->ahead_start = ra->start + ra->size;
@@ -577,6 +571,6 @@ unsigned long max_sane_readahead(unsigned long nr)
 	unsigned long inactive;
 	unsigned long free;
 
-	get_zone_counts(&active, &inactive, &free);
+	__get_zone_counts(&active, &inactive, &free, NODE_DATA(numa_node_id()));
 	return min(nr, (inactive + free) / 2);
 }