svn commit: r250219 - head/sys/vm

[John Baldwin]

On Friday, May 03, 2013 2:58:38 pm John Baldwin wrote:
> Author: jhb
> Date: Fri May  3 18:58:37 2013
> New Revision: 250219
> URL: http://svnweb.freebsd.org/changeset/base/250219
> 
> Log:
>   Fix two bugs in the current NUMA-aware allocation code:
>   - vm_phys_alloc_freelist_pages() can be called by vm_page_alloc_freelist()
>     to allocate a page from a specific freelist.  In the NUMA case it did not
>     properly map the public VM_FREELIST_* constants to the correct backing
>     freelists, nor did it try all NUMA domains for allocations from
>     VM_FREELIST_DEFAULT.

In practice this should never occur as only mips uses this function and the mips
code doesn't support multiple domains yet.

>   - vm_phys_alloc_pages() did not pin the thread and each call to
>     vm_phys_alloc_freelist_pages() fetched the current domain to choose
>     which freelist to use.  If a thread migrated domains during the loop
>     in vm_phys_alloc_pages() it could skip one of the freelists.  If the
>     other freelists were out of memory then it is possible that
>     vm_phys_alloc_pages() would fail to allocate a page even though pages
>     were available resulting in a panic in vm_page_alloc().

I have seen multiple instances of this panic in production loads however.

-- 
John Baldwin