> On Thu, 1 May 1997, David Whysong wrote:
>
> > > > SIGBUS: ayiee, couldnt allocate page table.
> >
> > Changing 16 --> 48 in free_area_init() of linux/mm/page_alloc.c solves
> > this problem on my machine. I think this should go into 2.0.31.
>
> I changed 128 --> 200 (echo "200 300 400" > /proc/sys/vm/freepages) and
> still had the problem. Increasing these values only makes the problem show
> up not so often, but it does _NOT_ solve the problem.
I agree; I did
# echo "128 256 512" > /proc/sys/vm/freepages
# make zImage MAKE="make -j"
And promptly got a signal 7. I do NOT understand why changing 16 --> 48
in free_area_init() has any effect on my machine; the relevant code is:
i = (end_mem - PAGE_OFFSET) >> (PAGE_SHIFT+7);
if (i < 16)
i = 16;
I have 32M of RAM, so if end_mem is 32M = 2^25, then i should be
(2^25-0) >> (12+7) = 64
So on my machine (assuming I understand this code correctly, which is
pretty far-fetched) i>16 anyway and changing from 16 to 48 shouldn't do
anything at all. It does, though... my system has been rock-solid ever
since I made the change.
Obviously my comment that this should go into 2.0.31 was premature; I need
to understand just why this little change seems to work for me in the
first place.
> I tried the tests with the old buffer.c code from 2.0.29: The problem
> showed up not so often, but still existed.
I don't know when this problem first showed up; for a long time I thought
it was flaky hardware and so I lived with it. Now I'm not so sure.
Dave
David Whysong
dwhysong@physics.ucsb.edu
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