svn commit: r281451 - head/sys/vm

[Scott Long]

> On Apr 12, 2015, at 12:21 AM, Dmitry Chagin <dchagin at FreeBSD.org> wrote:
> 
> Author: dchagin
> Date: Sun Apr 12 06:21:58 2015
> New Revision: 281451
> URL: https://svnweb.freebsd.org/changeset/base/281451
> 
> Log:
>  Rework r281162. Indeed, the flexible array member is preferable here.
> 
>  Suggested by:   Justin T. Gibbs
> 
>  MFC after:	3 days
> 
> Modified:
>  head/sys/vm/uma_core.c
>  head/sys/vm/uma_int.h

There’s still something wrong with this.  I have a machine with 28 cores (56 with hyperthreading) and 256GB of RAM, and ever since you committed r281162, it panics early in boot with a failed assertion.  It looks like the first few members of a uma_slab_t are getting overwritten accidentally, and somehow the padding of the extra member in the uma_zone_t was previously protecting it.  I don’t know the exact cause yet, but I must ask that you revert to r281161 in HEAD and stable/10 until the problem is resolved.

Thanks,
Scott