aa-150-read_write_tweaks

aa-150-read_write_tweaks

[Andrew Morton]

- Don't do flush_page_to_ram() on the page fault-in path.  That's
  handled in mm/memory.c, and filemap.c doesn't need to do it.

- In generic_file_write(), only set the page's Referenced bit once,
  when the write touches the start of the page.  This is a
  microoptimisation.  Seemingly a buggy one too - lseek exists...


=====================================

--- 2.4.19-pre3/mm/filemap.c~aa-150-read_write_tweaks	Tue Mar 19 19:49:02 2002
+++ 2.4.19-pre3-akpm/mm/filemap.c	Tue Mar 19 19:49:02 2002
@@ -1968,7 +1968,6 @@ success:
 	 * and possibly copy it over to another page..
 	 */
 	mark_page_accessed(page);
-	flush_page_to_ram(page);
 	return page;
 
 no_cached_page:
@@ -3089,8 +3088,15 @@ generic_file_write(struct file *file,con
 		}
 unlock:
 		kunmap(page);
+
+		/*
+		 * Mark the page accessed if we wrote the
+		 * beginning or we just did an lseek.
+		 */
+		if (!offset || !file->f_reada)
+			SetPageReferenced(page);
+
 		/* Mark it unlocked again and drop the page.. */
-		SetPageReferenced(page);
 		UnlockPage(page);
 		page_cache_release(page);
 


-