X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=mm%2Freadahead.c;h=8d6eeaaa6296f9fb2372cff059138cbdd4b89723;hb=cce03467f61534d8f68519495f26df0603ce678b;hp=0f142a40984b1674228e067f491159d42b13f32d;hpb=e6a27dba1cf83d871b2dfcd64f04f12a67e3f4d5;p=linux-2.6.git

diff --git a/mm/readahead.c b/mm/readahead.c
index 0f142a409..8d6eeaaa6 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -52,24 +52,13 @@ static inline unsigned long get_min_readahead(struct file_ra_state *ra)
 	return (VM_MIN_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 }
 
-static inline void reset_ahead_window(struct file_ra_state *ra)
-{
-	/*
-	 * ... but preserve ahead_start + ahead_size value,
-	 * see 'recheck:' label in page_cache_readahead().
-	 * Note: We never use ->ahead_size as rvalue without
-	 * checking ->ahead_start != 0 first.
-	 */
-	ra->ahead_size += ra->ahead_start;
-	ra->ahead_start = 0;
-}
-
 static inline void ra_off(struct file_ra_state *ra)
 {
 	ra->start = 0;
 	ra->flags = 0;
 	ra->size = 0;
-	reset_ahead_window(ra);
+	ra->ahead_start = 0;
+	ra->ahead_size = 0;
 	return;
 }
 
@@ -83,10 +72,10 @@ static unsigned long get_init_ra_size(unsigned long size, unsigned long max)
 {
 	unsigned long newsize = roundup_pow_of_two(size);
 
-	if (newsize <= max / 32)
-		newsize = newsize * 4;
+	if (newsize <= max / 64)
+		newsize = newsize * newsize;
 	else if (newsize <= max / 4)
-		newsize = newsize * 2;
+		newsize = max / 4;
 	else
 		newsize = max;
 	return newsize;
@@ -437,7 +426,8 @@ static int make_ahead_window(struct address_space *mapping, struct file *filp,
 		 * congestion.  The ahead window will any way be closed
 		 * in case we failed due to excessive page cache hits.
 		 */
-		reset_ahead_window(ra);
+		ra->ahead_start = 0;
+		ra->ahead_size = 0;
 	}
 
 	return ret;
@@ -530,11 +520,11 @@ page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra,
 	 * If we get here we are doing sequential IO and this was not the first
 	 * occurence (ie we have an existing window)
 	 */
+
 	if (ra->ahead_start == 0) {	 /* no ahead window yet */
 		if (!make_ahead_window(mapping, filp, ra, 0))
-			goto recheck;
+			goto out;
 	}
-
 	/*
 	 * Already have an ahead window, check if we crossed into it.
 	 * If so, shift windows and issue a new ahead window.
@@ -546,16 +536,11 @@ page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra,
 		ra->start = ra->ahead_start;
 		ra->size = ra->ahead_size;
 		make_ahead_window(mapping, filp, ra, 0);
-recheck:
-		/* prev_page shouldn't overrun the ahead window */
-		ra->prev_page = min(ra->prev_page,
-			ra->ahead_start + ra->ahead_size - 1);
 	}
 
 out:
 	return ra->prev_page + 1;
 }
-EXPORT_SYMBOL_GPL(page_cache_readahead);
 
 /*
  * handle_ra_miss() is called when it is known that a page which should have