Re: Kernel 2.6.9 Multiple Page Allocation Failures

[Stefan Schmidt <zaphodb@zaphods.net>]

On Fri, Nov 12, 2004 at 11:09:29PM +1100, Nick Piggin wrote:
> OK. Occasional page allocation failures are not a problem, although
> if it is an order-0 allocation it may be an idea to increase
> min_free_kbytes a bit more.
What about more than occasional but more like constant errors? ;)

> I think you said earlier that you had min_free_kbytes set to 8192?
> Well after applying my patch, the memory watermarks get squashed
> down, so you'd want to set it to at least 16384 afterward. Maybe
> more.
I took the default from 2.6.10-rc1-bk19 with your patch and doubled it. No
luck with the following values subsequently applied:
#vm.min_free_kbytes=3831
#vm.min_free_kbytes=7662
#vm.min_free_kbytes=15324
#vm.min_free_kbytes=61296
vm.min_free_kbytes=65535
Did not help against the page allocation errors or boosting up the machines
performance.

I got XFS filesystem corruption in the end which (just) perhaps was triggered by
page allocation errors for it says:
XFS internal error XFS_WANT_CORRUPTED_RETURN after several page allocation
errors for the application having XFS in its stack trace leading to:
kernel: xfs_force_shutdown(sdd5,0x8) called from line 1091 of file
        fs/xfs/xfs_trans.c.  Return address = 0xc0212e5c
kernel: Filesystem "sdd5": Corruption of in-memory data detected.
        Shutting down filesystem: sdd5
kernel: Please umount the filesystem, and rectify the problem(s)

Corruption of in-memory data sounds like something we would not want to
happen, right?

I attached full traces to http://oss.sgi.com/bugzilla/show_bug.cgi?id=345 which
is an rather old ticket dealing with page allocation errors and xfs but
perhaps it does fit.

	Stefan