Messages in this thread | | | Date | Wed, 23 Jan 2008 13:36:37 -0800 | From | Nishanth Aravamudan <> | Subject | Re: [PATCH] Fix boot problem in situations where the boot CPU is running on a memoryless node |
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On 23.01.2008 [13:14:26 -0800], Christoph Lameter wrote: > On Wed, 23 Jan 2008, Pekka Enberg wrote: > > > I think Mel said that their configuration did work with 2.6.23 > > although I also wonder how that's possible. AFAIK there has been some > > changes in the page allocator that might explain this. That is, if > > kmem_getpages() returned pages for memoryless node before, bootstrap > > would have worked. > > Regular kmem_getpages is called with GFP_THISNODE set. There was some > breakage in 2.6.22 and before with GFP_THISNODE returning pages from > the wrong node if a node had no memory. So it may have worked > accidentally and in an unsafe manner because the pages would have been > associated with the wrong node which could trigger bug ons and locking > troubles.
Right, so it might have functioned before, but the correctness was wobbly at best... Certainly the memoryless patch series has tightened that up, but we missed these SLAB issues.
I see that your patch fixed Olaf's machine, Pekka. Nice work on everyone's part tracking this stuff down.
Thanks, Nish
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