Messages in this thread | | | Date | Fri, 9 Nov 2007 16:14:55 +0000 | Subject | Re: [PATCH 6/6] Use one zonelist that is filtered by nodemask | From | (Mel Gorman) |
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On (09/11/07 07:45), Christoph Lameter didst pronounce: > On Fri, 9 Nov 2007, Mel Gorman wrote: > > > struct page * fastcall > > __alloc_pages(gfp_t gfp_mask, unsigned int order, > > struct zonelist *zonelist) > > { > > + /* > > + * Use a temporary nodemask for __GFP_THISNODE allocations. If the > > + * cost of allocating on the stack or the stack usage becomes > > + * noticable, allocate the nodemasks per node at boot or compile time > > + */ > > + if (unlikely(gfp_mask & __GFP_THISNODE)) { > > + nodemask_t nodemask; > > Hmmm.. This places a potentially big structure on the stack. nodemask can > contain up to 1024 bits which means 128 bytes. Maybe keep an array of > gfp_thisnode nodemasks (node_nodemask?) and use node_nodemask[nid]? >
That is what I was hinting at in the comment as a possible solution.
> > + > > + return __alloc_pages_internal(gfp_mask, order, > > + zonelist, nodemask_thisnode(numa_node_id(), &nodemask)); > > Argh.... GFP_THISNODE must use the nid passed to alloc_pages_node and > *not* the local numa node id. Only if the node specified to alloc_pages > nodes is -1 will this work. >
alloc_pages_node() calls __alloc_pages_nodemask() though where in this function if I'm reading it right is called without a node id. Given no other details on the nid, the current one seemed a logical choice.
What I did notice when rechecking is I left the warning about THISNODE in by accident :(
-- -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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