[PATCH] x86_64: Don't try to put kernel page tables beyond ZONE_DMA32.

For not fully explained reasons it broke mem=... on several setups.

Also minor cleanup.

Cc: axboe@suse.de

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 13 deletions

diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index eca60125efc3..ef84106c1509 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -262,19 +262,11 @@ static void __init find_early_table_space(unsigned long end)
         tables = round_up(puds * sizeof(pud_t), PAGE_SIZE) +
                  round_up(pmds * sizeof(pmd_t), PAGE_SIZE);
 
-        /* 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);
+        /* RED-PEN putting page tables only on node 0 could
+           cause a hotspot and fill up ZONE_DMA. The page tables
+           need roughly 0.5KB per GB. */
+        start = 0x8000;
+        table_start = find_e820_area(start, end, tables);
         if (table_start == -1UL)
                 panic("Cannot find space for the kernel page tables");