Re: [Bugme-new] [Bug 2019] New: Bug from the mm subsystem involving X (fwd)

["Martin J. Bligh" <mbligh@aracnet.com>]

Fix pfn_valid for architctures with discontiguous memory.
This only changes the NUMA definition, and it leaves the NUMA-Q
definition as was, because it's faster that way, it's in hotpaths,
and our memory is always contiguous.

diff -aurpN -X /home/fletch/.diff.exclude pfn_to_nid/include/asm-i386/mmzone.h pfn_valid/include/asm-i386/mmzone.h
--- pfn_to_nid/include/asm-i386/mmzone.h	Thu Feb  5 20:58:00 2004
+++ pfn_valid/include/asm-i386/mmzone.h	Thu Feb  5 22:08:57 2004
@@ -121,14 +121,19 @@ static inline struct pglist_data *pfn_to
 		+ __zone->zone_start_pfn;				\
 })
 #define pmd_page(pmd)		(pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
-/*
- * pfn_valid should be made as fast as possible, and the current definition 
- * is valid for machines that are NUMA, but still contiguous, which is what
- * is currently supported. A more generalised, but slower definition would
- * be something like this - mbligh:
- * ( pfn_to_pgdat(pfn) && ((pfn) < node_end_pfn(pfn_to_nid(pfn))) ) 
- */ 
+
+#ifdef CONFIG_X86_NUMAQ            /* we have contiguous memory on NUMA-Q */
 #define pfn_valid(pfn)          ((pfn) < num_physpages)
+#else
+static inline int pfn_valid(int pfn)
+{
+	int nid = pfn_to_nid(pfn);
+
+	if (nid >= 0)
+		return (pfn < node_end_pfn(nid));
+	return 0;
+}
+#endif
 
 extern int get_memcfg_numa_flat(void );
 /*

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