On Fri, Mar 5, 2010 at 10:41 AM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> On 03/04/2010 09:17 PM, Greg Thelen wrote:
>> On Thu, Mar 4, 2010 at 7:21 PM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
>>> On Thu, Mar 04, 2010 at 01:21:41PM -0800, Greg Thelen wrote:
>>>> On several systems I am seeing a boot panic if I use mmotm
>>>> (stamp-2010-03-02-18-38). If I remove
>>>> bootmem-avoid-dma32-zone-by-default.patch then no panic is seen. I
>>>> find that:
>>>> * 2.6.33 boots fine.
>>>> * 2.6.33 + mmotm w/o bootmem-avoid-dma32-zone-by-default.patch: boots fine.
>>>> * 2.6.33 + mmotm (including
>>>> bootmem-avoid-dma32-zone-by-default.patch): panics.
> ...
>>
>> Note: mmotm has been recently updated to stamp-2010-03-04-18-05. I
>> re-tested with 'make defconfig' to confirm the panic with this later
>> mmotm.
>
> please check
>
> [PATCH] early_res: double check with updated goal in alloc_memory_core_early
>
> Johannes Weiner pointed out that new early_res replacement for alloc_bootmem_node
> change the behavoir about goal.
> original bootmem one will try go further regardless of goal.
>
> and it will break his patch about default goal from MAX_DMA to MAX_DMA32...
> also broke uncommon machines with <=16M of memory.
> (really? our x86 kernel still can run on 16M system?)
>
> so try again with update goal.
>
> Reported-by: Greg Thelen <gthelen@xxxxxxxxxx>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
>
> ---
> mm/bootmem.c | 28 +++++++++++++++++++++++++---
> 1 file changed, 25 insertions(+), 3 deletions(-)
>
> Index: linux-2.6/mm/bootmem.c
> ===================================================================
> --- linux-2.6.orig/mm/bootmem.c
> +++ linux-2.6/mm/bootmem.c
> @@ -170,6 +170,28 @@ void __init free_bootmem_late(unsigned l
> }
>
> #ifdef CONFIG_NO_BOOTMEM
> +static void * __init ___alloc_memory_core_early(pg_data_t *pgdat, u64 size,
> + u64 align, u64 goal, u64 limit)
> +{
> + void *ptr;
> + unsigned long end_pfn;
> +
> + ptr = __alloc_memory_core_early(pgdat->node_id, size, align,
> + goal, limit);
> + if (ptr)
> + return ptr;
> +
> + /* check goal according */
> + end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages;
> + if ((end_pfn << PAGE_SHIFT) < (goal + size)) {
> + goal = pgdat->node_start_pfn << PAGE_SHIFT;
> + ptr = __alloc_memory_core_early(pgdat->node_id, size, align,
> + goal, limit);
> + }
> +
> + return ptr;
> +}
> +
> static void __init __free_pages_memory(unsigned long start, unsigned long end)
> {
> int i;
> @@ -836,7 +858,7 @@ void * __init __alloc_bootmem_node(pg_da
> return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
>
> #ifdef CONFIG_NO_BOOTMEM
> - return __alloc_memory_core_early(pgdat->node_id, size, align,
> + return ___alloc_memory_core_early(pgdat, size, align,
> goal, -1ULL);
> #else
> return ___alloc_bootmem_node(pgdat->bdata, size, align, goal, 0);
> @@ -920,7 +942,7 @@ void * __init __alloc_bootmem_node_nopan
> return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
>
> #ifdef CONFIG_NO_BOOTMEM
> - ptr = __alloc_memory_core_early(pgdat->node_id, size, align,
> + ptr = ___alloc_memory_core_early(pgdat, size, align,
> goal, -1ULL);
> #else
> ptr = alloc_arch_preferred_bootmem(pgdat->bdata, size, align, goal, 0);
> @@ -980,7 +1002,7 @@ void * __init __alloc_bootmem_low_node(p
> return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
>
> #ifdef CONFIG_NO_BOOTMEM
> - return __alloc_memory_core_early(pgdat->node_id, size, align,
> + return ___alloc_memory_core_early(pgdat, size, align,
> goal, ARCH_LOW_ADDRESS_LIMIT);
> #else
> return ___alloc_bootmem_node(pgdat->bdata, size, align,
>
On my 256MB VM, which detected the problem starting this thread, the
"double check with updated goal in alloc_memory_core_early" patch
(above) boots without panic.
My initial impression is that this fixes the reported problem. Note:
I have not tested to see if any other issues are introduced.
--
Greg
--
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