[PATCH v2 16/22] ARM: mm: cleanup checks for membank overlap with vmalloc area

On 8/12/2012 12:36 AM, Nicolas Pitre wrote:

On Fri, 10 Aug 2012, Cyril Chemparathy wrote:

quoted

On Keystone platforms, physical memory is entirely outside the 32-bit
addressible range.  Therefore, the (bank->start > ULONG_MAX) check below marks
the entire system memory as highmem, and this causes unpleasentness all over.

This patch eliminates the extra bank start check (against ULONG_MAX) by
checking bank->start against the physical address corresponding to vmalloc_min
instead.

In the process, this patch also cleans up parts of the highmem sanity check
code by removing what has now become a redundant check for banks that entirely
overlap with the vmalloc range.

Are you sure of this?  The code that you removed not only checks for
banks that fall into the vmalloc area, but it also skipp them.  This is
now lost.

I almost missed out on this email...

The check is not quite lost, we still have the following in the 
!CONFIG_HIGHMEM block:

	if (highmem) {
		printk(...);
		continue;
	}

The change is that highmem is now set outside the #ifdef when 
(bank->start >= vmalloc_limit), and therefore the check is truly redundant.

quoted

Signed-off-by: Cyril Chemparathy <redacted>
Signed-off-by: Vitaly Andrianov <redacted>
---
  arch/arm/mm/mmu.c |   19 +------------------
  1 file changed, 1 insertion(+), 18 deletions(-)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index f764c03..3d685c6 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c

@@ -901,15 +901,12 @@ void __init sanity_check_meminfo(void)
  		struct membank *bank = &meminfo.bank[j];
  		*bank = meminfo.bank[i];

-		if (bank->start > ULONG_MAX)
-			highmem = 1;
-
-#ifdef CONFIG_HIGHMEM
  		if (bank->start >= vmalloc_limit)
  			highmem = 1;

  		bank->highmem = highmem;

+#ifdef CONFIG_HIGHMEM
  		/*
  		 * Split those memory banks which are partially overlapping
  		 * the vmalloc area greatly simplifying things later.

@@ -932,8 +929,6 @@ void __init sanity_check_meminfo(void)
  			bank->size = vmalloc_limit - bank->start;
  		}
  #else
-		bank->highmem = highmem;
-
  		/*
  		 * Highmem banks not allowed with !CONFIG_HIGHMEM.
  		 */

@@ -946,18 +941,6 @@ void __init sanity_check_meminfo(void)
  		}

  		/*
-		 * Check whether this memory bank would entirely overlap
-		 * the vmalloc area.
-		 */
-		if (bank->start >= vmalloc_limit) {
-			printk(KERN_NOTICE "Ignoring RAM at %.8llx-%.8llx "
-			       "(vmalloc region overlap).\n",
-			       (unsigned long long)bank->start,
-			       (unsigned long long)bank->start + bank->size - 1);
-			continue;
-		}
-
-		/*
  		 * Check whether this memory bank would partially overlap
  		 * the vmalloc area.
  		 */
--

1.7.9.5

-- 
Thanks
- Cyril