bdflush synchronous IO on prerelease-diff

[Marcelo Tosatti]

Hi Linus, 

I've noticed you changed bdflush to do synchronous IO on page_launder().

That seems to be a performance problem, since kflushd will have to wait
for dirty buffers to get synced instead looping on the inactive dirty
list more often. 

Here is a patch to change this. 

--- linux.orig/fs/buffer.c      Wed Jan  3 22:43:24 2001
+++ linux/fs/buffer.c   Thu Jan  4 00:28:50 2001
@@ -2710,7 +2710,7 @@
 
                flushed = flush_dirty_buffers(0);
                if (free_shortage())
-                       flushed += page_launder(GFP_KERNEL, 1);
+                       flushed += page_launder(GFP_KERNEL, 0);
 
                /*
                 * If there are still a lot of dirty buffers around,