commented early_printk patch because of rejects.

[linux-flexiantxendom0-3.2.10.git] / mm / readahead.c

diff --git a/mm/readahead.c b/mm/readahead.c
index d5db634..69f24b9 100644 (file)
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -96,8 +96,6 @@ static int read_pages(struct address_space *mapping, struct file *filp,
        struct pagevec lru_pvec;
        int ret = 0;
 
-       current->flags |= PF_READAHEAD;
-
        if (mapping->a_ops->readpages) {
                ret = mapping->a_ops->readpages(filp, mapping, pages, nr_pages);
                goto out;
@@ -118,7 +116,6 @@ static int read_pages(struct address_space *mapping, struct file *filp,
        }
        pagevec_lru_add(&lru_pvec);
 out:
-       current->flags &= ~PF_READAHEAD;
        return ret;
 }
 
@@ -263,8 +260,8 @@ out:
  * Chunk the readahead into 2 megabyte units, so that we don't pin too much
  * memory at once.
  */
-int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
-                       unsigned long offset, unsigned long nr_to_read)
+int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
+               unsigned long offset, unsigned long nr_to_read)
 {
        int ret = 0;
 
@@ -292,6 +289,22 @@ int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 }
 
 /*
+ * This version skips the IO if the queue is read-congested, and will tell the
+ * block layer to abandon the readahead if request allocation would block.
+ *
+ * force_page_cache_readahead() will ignore queue congestion and will block on
+ * request queues.
+ */
+int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
+                       unsigned long offset, unsigned long nr_to_read)
+{
+       if (!bdi_read_congested(mapping->backing_dev_info))
+               return __do_page_cache_readahead(mapping, filp,
+                                               offset, nr_to_read);
+       return 0;
+}
+
+/*
  * Check how effective readahead is being.  If the amount of started IO is
  * less than expected then the file is partly or fully in pagecache and
  * readahead isn't helping.  Shrink the window.