Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 3 Mar 1997 16:40:31 -0500 (EST)
From:      Thomas David Rivers <ponds!rivers@dg-rtp.dg.com>
To:        ponds!freefall.cdrom.com!freebsd-hackers
Subject:   Follow-up on Terry's suggestion for "dup alloc" problem.
Message-ID:  <199703032140.QAA24012@lakes.water.net>

next in thread | raw e-mail | index | archive | help

Just to follow-up.

Terry suggested I rebuild a kernel without BOUNCE_BUFFERS
defined.  This sounded like a plausible avenue of investigation,
especially since I'm wondering, myself, if something has gone
wrong with buffer management.   So, I commented out the BOUNCE_BUFFERS from
the GENERIC definition.  (GENERIC is used by the release makefile
to produce the BOOTMFS definition; which is what builds the 
installation kernel) and rebuilt my kernel.

Here's an example compile line. I've cut machdep.c from the log
of this build; since it's so dependent on BOUNCE_BUFFERS.  You'll
notice some reformating to fit in 80 columns:

   cc -c -O -W -Wreturn-type -Wcomment -Wredundant-decls -Wimplicit  
   -nostdinc -I. -I../.. -I../../sys -I../../../include -DBOOTMFS -DI586_CPU 
   -DI486_CPU -DI386_CPU -DMFS_ROOT=1450 -DUSERCONFIG_BOOT -DMAXCONS=4 
   -DNFS_NOSERVER -DMFS -DATAPI -DVISUAL_USERCONFIG -DUSERCONFIG -DUCONSOLE 
   -DSCSI_DELAY=15 -DCOMPAT_43 -DCD9660 -DMSDOSFS -DNFS -DFFS -DINET 
   -DMATH_EMULATE -DKERNEL -Di386 -DLOAD_ADDRESS=0xF0100000  
   ../../i386/i386/machdep.c


When I ran my test case against this, I still got the corrupted
disk block...  so, it doesn't appear that BOUNCE_BUFFERS are the
problem here.  

 By the way, I did some checking around and did discover BOUNCE_BUFFERS 
could change things for non-SCSI devices;  but the changes would basically 
be where some buffers are allocated.  See machdep.c and vm_machdep.c.  The 
device driver is responsible for "bouncing" a buffer when the
situation warrants... 

 Someone else in private mail had suggested removing the -DI586_CPU
and -DI486_CPU.  I don't think it will matter since the CPU
is probed correctly... but I'm willing to give it a shot.

 Again, for those who are reading this for the first time; this is
a 2.1.6.1 install kernel, running on a 386dx with 12 meg of memory.
The problem I'm trying to debug is causing a daily "dup alloc" panic
on my news server, and it has occurred since 2.1.0...  The recent
mail archives will have a summary of my current thoughts.
Look for "dup alloc" and "daily panic" in the Subject:...

	 - Thanks -
	- Dave Rivers -



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199703032140.QAA24012>