Re: [Bug 8464] New: autoreconf: page allocation failure. order:2, mode:0x84020

[Mel Gorman]

On (10/05/07 15:11), Christoph Lameter didst pronounce:
> On Thu, 10 May 2007, Mel Gorman wrote:
> 
> > I see the gfpmask was 0x84020. That doesn't look like __GFP_WAIT was set,
> > right? Does that mean that SLUB is trying to allocate pages atomically? If so,
> > it would explain why this situation could still occur even though high-order
> > allocations that could sleep would succeed.
> 
> SLUB is following the gfp mask of the caller like all well behaved slab 
> allocators do. If the caller does not set __GFP_WAIT then the page 
> allocator also cannot wait.

Then SLUB should not use the higher orders for slab allocations that cannot
sleep during allocations. What could be done in the longer term is decide
how to tell kswapd to keep pages free at an order other than 0 when it is
known there are a large number of high-order long-lived allocations like this.

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab
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