[PATCH 02/10] readahead: mmap read-around simplification

[Fengguang Wu]

Fold file_ra_state.mmap_hit into file_ra_state.mmap_miss
and make it an int.

Signed-off-by: Fengguang Wu <wfg@xxxxxxxxxxxxxxxx>
---
 include/linux/fs.h |    3 +--
 mm/filemap.c       |    4 ++--
 2 files changed, 3 insertions(+), 4 deletions(-)

--- linux-2.6.22-rc6-mm1.orig/include/linux/fs.h
+++ linux-2.6.22-rc6-mm1/include/linux/fs.h
@@ -777,8 +777,7 @@ struct file_ra_state {
 					   there are only # of pages ahead */
 
 	unsigned int ra_pages;		/* Maximum readahead window */
-	unsigned long mmap_hit;		/* Cache hit stat for mmap accesses */
-	unsigned long mmap_miss;	/* Cache miss stat for mmap accesses */
+	int mmap_miss;			/* Cache miss stat for mmap accesses */
 	unsigned long prev_index;	/* Cache last read() position */
 	unsigned int prev_offset;	/* Offset where last read() ended in a page */
 };
--- linux-2.6.22-rc6-mm1.orig/mm/filemap.c
+++ linux-2.6.22-rc6-mm1/mm/filemap.c
@@ -1389,7 +1389,7 @@ retry_find:
 		 * Do we miss much more than hit in this file? If so,
 		 * stop bothering with read-ahead. It will only hurt.
 		 */
-		if (ra->mmap_miss > ra->mmap_hit + MMAP_LOTSAMISS)
+		if (ra->mmap_miss > MMAP_LOTSAMISS)
 			goto no_cached_page;
 
 		/*
@@ -1415,7 +1415,7 @@ retry_find:
 	}
 
 	if (!did_readaround)
-		ra->mmap_hit++;
+		ra->mmap_miss--;
 
 	/*
 	 * We have a locked page in the page cache, now we need to check

--
-
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