Graceful failure instead of panicking in kmem_malloc
Kris Kennaway
kris at FreeBSD.org
Tue Jan 8 16:30:25 PST 2008
Bharma Ji wrote:
> In FreeBSD 6_2, if kmem_malloc is unable to find space it panics. The
> relevant code is in vm_kern.c
> if ((flags & M_NOWAIT) == 0)
> panic("kmem_malloc(%ld): kmem_map too small: %ld
> total allocated",
> (long)size, (long)map->size);
>
> Is there any way to make the system log and then gracefully shut off instead
> of panicking?
Not really, because those actions require memory allocation. The real
fix is to either
a) avoid running out of memory in the first place by tuning vm.kmem_size
b) perhaps trying harder to avoid panicking by first trying to more
aggressively reclaim memory.
You can try
http://www.freebsd.org/~pjd/patches/vm_kern.c.2.patch
which implements b) (patch against 7.0, but might apply to 6.2 unchanged).
Kris
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