RE: OOPS in do_try_to_free_pages with VERY large software RAID array

[Rechenberg, Andrew]

Kevin,

I tried patching md by hand since you're patch is for 2.5 but I'm having
some issues.  When I try to make bzImage I'm getting the following
error:

md.c:139: `single_release' undeclared here (not in a function)
md.c:139: initializer element is not constant
md.c:139: (near initialization for `md_state_fops.release')
md.c:140: initializer element is not constant
md.c:140: (near initialization for `md_state_fops')
md.c: In function `md_state_seq_show':
md.c:3219: warning: passing arg 1 of pointer to function from
incompatible pointer type
md.c: In function `md_state_open_fs':
md.c:3238: warning: implicit declaration of function `single_open'
make[3]: *** [md.o] Error 1
make[3]: Leaving directory `/usr/src/linux-flux/drivers/md'
make[2]: *** [first_rule] Error 2
make[2]: Leaving directory `/usr/src/linux-flux/drivers/md'
make[1]: *** [_subdir_md] Error 2
make[1]: Leaving directory `/usr/src/linux-flux/drivers'
make: *** [_dir_drivers] Error 2

Can you tell me if the single_release is a 2.5 "thing?"  Can you point
me in the right direction as to how to fix this problem?.

Thanks,
Andy.

-----Original Message-----
From: Kevin P. Fleming [mailto:[e-mail]] 
Sent: Monday, March 10, 2003 2:48 PM
To: Martin J. Bligh
Cc: Rechenberg, Andrew; [e-mail]
Subject: Re: OOPS in do_try_to_free_pages with VERY large software RAID
array

Martin J. Bligh wrote:
> At a wild guess (OK, I only looked for about 1 minute), 
> md_status_read_proc is generating more than 4K of information, and 
> overwriting the end of it's 4K page. Throw some debug in there, and 
> get it to printk how much of the buffer it thinks it's using (just 
> printk sz every time it changes it). If it's > 4K, convert it to the 
> seq_file interface.
> 
> May not be it, but it seems likely given the unusual scale of what 
> you're doing, and it's easy to check.
> 
> M.

I posted a patch to do exactly this last week to the Linux-RAID mailing
list. If 
you check the archives you should find it. This problem also occurs if
you use 
the device-mapper under 2.5.X, because it makes all 256 md minors appear
in the 
tables and /proc/mdstat wants to tell you about all of them.