Re: balance_dirty_pages broken

[Andrew Morton <akpm@digeo.com>]

Doug Ledford wrote:
> 
> On Thu, Oct 17, 2002 at 01:22:46AM -0400, Doug Ledford wrote:
> > Sure, coming under separate cover.
> 
> Actually, this isn't needed now I assume ;-)

Well I was rather interested in seeing it to find out why your
compile is busted.  You seem to be very protective of the compiler
error messages ;)

> ...
> Patch solves the problem.  Writes don't hang and Shift-ScrollLock shows a
> reasonable number for dirty now.

OK, thanks.  That patch still doesn't fix the ramdisk's current problems
so I'll send a minimal fix for this one to Linus.

Namely:



--- 2.5.43/drivers/block/rd.c~rd-dirty-fix	Wed Oct 16 22:46:02 2002
+++ 2.5.43-akpm/drivers/block/rd.c	Wed Oct 16 22:47:39 2002
@@ -51,6 +51,7 @@
 #include <linux/init.h>
 #include <linux/devfs_fs_kernel.h>
 #include <linux/buffer_head.h>		/* for invalidate_bdev() */
+#include <linux/backing-dev.h>
 #include <asm/uaccess.h>
 
 /*
@@ -351,6 +352,10 @@ static struct file_operations initrd_fop
 
 #endif
 
+static struct backing_dev_info rd_backing_dev_info = {
+	.ra_pages	= 0,	/* No readahead */
+	.memory_backed	= 1,	/* Does not contribute to dirty memory */
+};
 
 static int rd_open(struct inode * inode, struct file * filp)
 {
@@ -379,6 +384,7 @@ static int rd_open(struct inode * inode,
 		rd_bdev[unit]->bd_openers++;
 		rd_bdev[unit]->bd_block_size = rd_blocksize;
 		rd_bdev[unit]->bd_inode->i_mapping->a_ops = &ramdisk_aops;
+		rd_bdev[unit]->bd_inode->i_mapping->backing_dev_info = &rd_backing_dev_info;
 		rd_bdev[unit]->bd_inode->i_size = rd_length[unit];
 		rd_bdev[unit]->bd_queue = &blk_dev[MAJOR_NR].request_queue;
 		rd_bdev[unit]->bd_disk = get_disk(rd_disks[unit]);

.