Re: [PATCH 1/3] memblock, nobootmem: Add memblock_virt_alloc_low()

[Yinghai Lu]

On Tue, Jan 28, 2014 at 12:17 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, Jan 28, 2014 at 10:22 AM, Russell King - ARM Linux
> <linux@xxxxxxxxxxxxxxxx> wrote:
>>
>> Hence, having ARCH_LOW_ADDRESS_LIMIT set to 4GB-1 by default seems to be
>> completely rediculous - and presumably this also fails on x86_32 if it
>> returns memory up at 4GB.
>
> Agreed. That looks broken even on x86-32. The low address limit is not
> even *close* to 4GB in general on 32-bit, since you not only have the
> TASK_SIZE, you have the kmap and the vmalloc area. On x86-32,
> ARCH_LOW_ADDRESS_LIMIT should be MAXMEM, which iirc is somewhere
> around 890MB or so. Not 4G.
>

yeah, Please check the patch that one minute ago.

Subject: [PATCH] memblock: Add limit checking to memblock_virt_alloc

In original bootmem wrapper for memblock, we have limit checking.

Add it to memblock_virt_alloc, to address arm and x86 booting crash.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

---
 mm/memblock.c |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-2.6/mm/memblock.c
===================================================================
--- linux-2.6.orig/mm/memblock.c
+++ linux-2.6/mm/memblock.c
@@ -1077,6 +1077,9 @@ static void * __init memblock_virt_alloc
     if (!align)
         align = SMP_CACHE_BYTES;

+    if (max_addr > memblock.current_limit)
+        max_addr = memblock.current_limit;
+
 again:
     alloc = memblock_find_in_range_node(size, align, min_addr, max_addr,
                         nid);

Thanks

Yinghai
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