readahead: sanify file_ra_state names

@@ -139,10 +139,10 @@ static int ext3_readdir(struct file * fi
 			pgoff_t index = map_bh.b_blocknr >>
 					(PAGE_CACHE_SHIFT - inode->i_blkbits);
 			if (!ra_has_index(&filp->f_ra, index))
-				page_cache_readahead_ondemand(
+				page_cache_sync_readahead(
 					sb->s_bdev->bd_inode->i_mapping,
 					&filp->f_ra, filp,
-					NULL, index, 1);
+					index, 1);
 			filp->f_ra.prev_index = index;
 			bh = ext3_bread(NULL, inode, blk, 0, &err);
 		}

@@ -138,10 +138,10 @@ static int ext4_readdir(struct file * fi
 			pgoff_t index = map_bh.b_blocknr >>
 					(PAGE_CACHE_SHIFT - inode->i_blkbits);
 			if (!ra_has_index(&filp->f_ra, index))
-				page_cache_readahead_ondemand(
+				page_cache_sync_readahead(
 					sb->s_bdev->bd_inode->i_mapping,
 					&filp->f_ra, filp,
-					NULL, index, 1);
+					index, 1);
 			filp->f_ra.prev_index = index;
 			bh = ext4_bread(NULL, inode, blk, 0, &err);
 		}

@@ -304,8 +304,8 @@ __generic_file_splice_read(struct file *
 	 * readahead/allocate the rest.
 	 */
 	if (spd.nr_pages < nr_pages)
-		page_cache_readahead_ondemand(mapping, &in->f_ra, in,
-				NULL, index, req_pages - spd.nr_pages);
+		page_cache_sync_readahead(mapping, &in->f_ra, in,
+				index, req_pages - spd.nr_pages);
 
 	while (spd.nr_pages < nr_pages) {
 		/*

@@ -360,7 +360,7 @@ __generic_file_splice_read(struct file *
 		page = pages[page_nr];
 
 		if (PageReadahead(page))
-			page_cache_readahead_ondemand(mapping, &in->f_ra, in,
+			page_cache_async_readahead(mapping, &in->f_ra, in,
 					page, index, req_pages - page_nr);
 
 		/*

@@ -1146,12 +1146,20 @@ int do_page_cache_readahead(struct addre
 			pgoff_t offset, unsigned long nr_to_read);
 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
 			pgoff_t offset, unsigned long nr_to_read);
-unsigned long page_cache_readahead_ondemand(struct address_space *mapping,
-			  struct file_ra_state *ra,
-			  struct file *filp,
-			  struct page *page,
-			  pgoff_t offset,
-			  unsigned long size);
+
+void page_cache_sync_readahead(struct address_space *mapping,
+			       struct file_ra_state *ra,
+			       struct file *filp,
+			       pgoff_t offset,
+			       unsigned long size);
+
+void page_cache_async_readahead(struct address_space *mapping,
+				struct file_ra_state *ra,
+				struct file *filp,
+				struct page *pg,
+				pgoff_t offset,
+				unsigned long size);
+
 unsigned long max_sane_readahead(unsigned long nr);
 
 /* Do stack extension */

@@ -913,15 +913,15 @@ void do_generic_mapping_read(struct addr
 find_page:
 		page = find_get_page(mapping, index);
 		if (!page) {
-			page_cache_readahead_ondemand(mapping,
-					&ra, filp, page,
+			page_cache_sync_readahead(mapping,
+					&ra, filp,
 					index, last_index - index);
 			page = find_get_page(mapping, index);
 			if (unlikely(page == NULL))
 				goto no_cached_page;
 		}
 		if (PageReadahead(page)) {
-			page_cache_readahead_ondemand(mapping,
+			page_cache_async_readahead(mapping,
 					&ra, filp, page,
 					index, last_index - index);
 		}

@@ -1382,14 +1382,14 @@ retry_find:
 	 */
 	if (VM_SequentialReadHint(vma)) {
 		if (!page) {
-			page_cache_readahead_ondemand(mapping, ra, file, page,
+			page_cache_sync_readahead(mapping, ra, file,
 							   fdata->pgoff, 1);
 			page = find_lock_page(mapping, fdata->pgoff);
 			if (!page)
 				goto no_cached_page;
 		}
 		if (PageReadahead(page)) {
-			page_cache_readahead_ondemand(mapping, ra, file, page,
+			page_cache_async_readahead(mapping, ra, file, page,
 							   fdata->pgoff, 1);
 		}
 	}

129 lines not on this page · raw message

@@ -768,16 +768,12 @@ struct fown_struct {
 
 /*
  * Track a single file's readahead state
- *
- *  ================#============|==================#==================|
- *                  ^            ^                  ^                  ^
- *  file_ra_state.la_index    .ra_index   .lookahead_index   .readahead_index
  */
 struct file_ra_state {
-	pgoff_t la_index;               /* enqueue time */
-	pgoff_t ra_index;               /* begin offset */
-	pgoff_t lookahead_index;        /* time to do next readahead */
-	pgoff_t readahead_index;        /* end offset */
+	pgoff_t start;                  /* where readahead started */
+	unsigned long size;             /* # of readahead pages */
+	unsigned long async_size;       /* do asynchronous readahead when
+					   there are only # of pages ahead */
 
 	unsigned long ra_pages;		/* Maximum readahead window */
 	unsigned long mmap_hit;		/* Cache hit stat for mmap accesses */

@@ -787,59 +783,14 @@ struct file_ra_state {
 };
 
 /*
- * Measuring read-ahead sizes.
- *
- *                  |----------- readahead size ------------>|
- *  ===#============|==================#=====================|
- *     |------- invoke interval ------>|-- lookahead size -->|
- */
-static inline unsigned long ra_readahead_size(struct file_ra_state *ra)
-{
-	return ra->readahead_index - ra->ra_index;
-}
-
-static inline unsigned long ra_lookahead_size(struct file_ra_state *ra)
-{
-	return ra->readahead_index - ra->lookahead_index;
-}
-
-static inline unsigned long ra_invoke_interval(struct file_ra_state *ra)
-{
-	return ra->lookahead_index - ra->la_index;
-}
-
-/*
  * Check if @index falls in the readahead windows.
  */
 static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
 {
-	return (index >= ra->la_index &&
-		index <  ra->readahead_index);
-}
-
-/*
- * Where is the old read-ahead and look-ahead?
- */
-static inline void ra_set_index(struct file_ra_state *ra,
-				pgoff_t la_index, pgoff_t ra_index)
-{
-	ra->la_index = la_index;
-	ra->ra_index = ra_index;
+	return (index >= ra->start &&
+		index <  ra->start + ra->size);
 }
 
-/*
- * Where is the new read-ahead and look-ahead?
- */
-static inline void ra_set_size(struct file_ra_state *ra,
-				unsigned long ra_size, unsigned long la_size)
-{
-	ra->readahead_index = ra->ra_index + ra_size;
-	ra->lookahead_index = ra->ra_index + ra_size - la_size;
-}
-
-unsigned long ra_submit(struct file_ra_state *ra,
-		       struct address_space *mapping, struct file *filp);
-
 struct file {
 	/*
 	 * fu_list becomes invalid after file_free is called and queued via

129 lines not on this page · raw message