[PATCH] x86_64: Allow kernel page tables upto the end of memory

[safe/jmp/linux-2.6] / arch / x86_64 / mm / init.c

diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index e938678..eca6012 100644 (file)
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -255,14 +255,26 @@ static void __init phys_pud_init(pud_t *pud, unsigned long address, unsigned lon
 
 static void __init find_early_table_space(unsigned long end)
 {
-       unsigned long puds, pmds, tables;
+       unsigned long puds, pmds, tables, start;
 
        puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
        pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
        tables = round_up(puds * sizeof(pud_t), PAGE_SIZE) +
                 round_up(pmds * sizeof(pmd_t), PAGE_SIZE);
 
-       table_start = find_e820_area(0x8000, __pa_symbol(&_text), tables);
+       /* Put page tables beyond the DMA zones if possible.
+          RED-PEN might be better to spread them out more over
+          memory to avoid hotspots */
+       if (end > MAX_DMA32_PFN<<PAGE_SHIFT)
+               start = MAX_DMA32_PFN << PAGE_SHIFT;
+       else if (end > MAX_DMA_PFN << PAGE_SHIFT)
+               start = MAX_DMA_PFN << PAGE_SHIFT;
+       else
+               start = 0x8000;
+
+       table_start = find_e820_area(start, end, tables);
+       if (table_start == -1)
+               table_start = find_e820_area(0x8000, end, tables);
        if (table_start == -1UL)
                panic("Cannot find space for the kernel page tables");