X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=mm%2Freadahead.c;h=c9c50ca1ec3866b839a85173f3d416a1b17211d1;hb=d52b3815a52456dcf1a45fbc344e23bb643b2bda;hp=4a58befbde4a5f157f6c5372d0420ea9c5390e71;hpb=f4e6b498d6e06742d72706ef50593a9c4dd72214;p=mv-sheeva.git

diff --git a/mm/readahead.c b/mm/readahead.c
index 4a58befbde4..c9c50ca1ec3 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -22,16 +22,8 @@ void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
 }
 EXPORT_SYMBOL(default_unplug_io_fn);
 
-/*
- * Convienent macros for min/max read-ahead pages.
- * Note that MAX_RA_PAGES is rounded down, while MIN_RA_PAGES is rounded up.
- * The latter is necessary for systems with large page size(i.e. 64k).
- */
-#define MAX_RA_PAGES	(VM_MAX_READAHEAD*1024 / PAGE_CACHE_SIZE)
-#define MIN_RA_PAGES	DIV_ROUND_UP(VM_MIN_READAHEAD*1024, PAGE_CACHE_SIZE)
-
 struct backing_dev_info default_backing_dev_info = {
-	.ra_pages	= MAX_RA_PAGES,
+	.ra_pages	= VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE,
 	.state		= 0,
 	.capabilities	= BDI_CAP_MAP_COPY,
 	.unplug_io_fn	= default_unplug_io_fn,
@@ -66,28 +58,25 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
 			int (*filler)(void *, struct page *), void *data)
 {
 	struct page *page;
-	struct pagevec lru_pvec;
 	int ret = 0;
 
-	pagevec_init(&lru_pvec, 0);
-
 	while (!list_empty(pages)) {
 		page = list_to_page(pages);
 		list_del(&page->lru);
-		if (add_to_page_cache(page, mapping, page->index, GFP_KERNEL)) {
+		if (add_to_page_cache_lru(page, mapping,
+					page->index, GFP_KERNEL)) {
 			page_cache_release(page);
 			continue;
 		}
+		page_cache_release(page);
+
 		ret = filler(data, page);
-		if (!pagevec_add(&lru_pvec, page))
-			__pagevec_lru_add(&lru_pvec);
-		if (ret) {
+		if (unlikely(ret)) {
 			put_pages_list(pages);
 			break;
 		}
 		task_io_account_read(PAGE_CACHE_SIZE);
 	}
-	pagevec_lru_add(&lru_pvec);
 	return ret;
 }
 
@@ -97,7 +86,6 @@ static int read_pages(struct address_space *mapping, struct file *filp,
 		struct list_head *pages, unsigned nr_pages)
 {
 	unsigned page_idx;
-	struct pagevec lru_pvec;
 	int ret;
 
 	if (mapping->a_ops->readpages) {
@@ -107,19 +95,15 @@ static int read_pages(struct address_space *mapping, struct file *filp,
 		goto out;
 	}
 
-	pagevec_init(&lru_pvec, 0);
 	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 		struct page *page = list_to_page(pages);
 		list_del(&page->lru);
-		if (!add_to_page_cache(page, mapping,
+		if (!add_to_page_cache_lru(page, mapping,
 					page->index, GFP_KERNEL)) {
 			mapping->a_ops->readpage(filp, page);
-			if (!pagevec_add(&lru_pvec, page))
-				__pagevec_lru_add(&lru_pvec);
-		} else
-			page_cache_release(page);
+		}
+		page_cache_release(page);
 	}
-	pagevec_lru_add(&lru_pvec);
 	ret = 0;
 out:
 	return ret;
@@ -157,20 +141,19 @@ __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 	/*
 	 * Preallocate as many pages as we will need.
 	 */
-	read_lock_irq(&mapping->tree_lock);
 	for (page_idx = 0; page_idx < nr_to_read; page_idx++) {
 		pgoff_t page_offset = offset + page_idx;
 
 		if (page_offset > end_index)
 			break;
 
+		rcu_read_lock();
 		page = radix_tree_lookup(&mapping->page_tree, page_offset);
+		rcu_read_unlock();
 		if (page)
 			continue;
 
-		read_unlock_irq(&mapping->tree_lock);
 		page = page_cache_alloc_cold(mapping);
-		read_lock_irq(&mapping->tree_lock);
 		if (!page)
 			break;
 		page->index = page_offset;
@@ -179,7 +162,6 @@ __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 			SetPageReadahead(page);
 		ret++;
 	}
-	read_unlock_irq(&mapping->tree_lock);
 
 	/*
 	 * Now start the IO.  We ignore I/O errors - if the page is not
@@ -251,6 +233,12 @@ unsigned long max_sane_readahead(unsigned long nr)
 		+ node_page_state(numa_node_id(), NR_FREE_PAGES)) / 2);
 }
 
+static int __init readahead_init(void)
+{
+	return bdi_init(&default_backing_dev_info);
+}
+subsys_initcall(readahead_init);
+
 /*
  * Submit IO for the read-ahead request in file_ra_state.
  */
@@ -379,6 +367,29 @@ ondemand_readahead(struct address_space *mapping,
 						offset, req_size, 0);
 	}
 
+	/*
+	 * Hit a marked page without valid readahead state.
+	 * E.g. interleaved reads.
+	 * Query the pagecache for async_size, which normally equals to
+	 * readahead size. Ramp it up and use it as the new readahead size.
+	 */
+	if (hit_readahead_marker) {
+		pgoff_t start;
+
+		read_lock_irq(&mapping->tree_lock);
+		start = radix_tree_next_hole(&mapping->page_tree, offset, max+1);
+		read_unlock_irq(&mapping->tree_lock);
+
+		if (!start || start - offset > max)
+			return 0;
+
+		ra->start = start;
+		ra->size = start - offset;	/* old async_size */
+		ra->size = get_next_ra_size(ra, max);
+		ra->async_size = ra->size;
+		goto readit;
+	}
+
 	/*
 	 * It may be one of
 	 * 	- first read on start of file
@@ -390,16 +401,6 @@ ondemand_readahead(struct address_space *mapping,
 	ra->size = get_init_ra_size(req_size, max);
 	ra->async_size = ra->size > req_size ? ra->size - req_size : ra->size;
 
-	/*
-	 * Hit on a marked page without valid readahead state.
-	 * E.g. interleaved reads.
-	 * Not knowing its readahead pos/size, bet on the minimal possible one.
-	 */
-	if (hit_readahead_marker) {
-		ra->start++;
-		ra->size = get_next_ra_size(ra, max);
-	}
-
 readit:
 	return ra_submit(ra, mapping, filp);
 }