On 03/05/2010 03:58 PM, Johannes Weiner wrote:
> Hello Yinghai,
>
> On Fri, Mar 05, 2010 at 10:41:56AM -0800, Yinghai Lu 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.
>
> Thanks for the patch, it seems to be correct.
>
> However, I have a more generic question about it, regarding the future of the
> early_res allocator.
>
> Did you plan on keeping the bootmem API for longer? Because my impression was,
> emulating it is a temporary measure until all users are gone and bootmem can
> be finally dropped.
that depends on every arch maintainer.
user can compare them on x86 to check if...
next step will be make fw_mem_map to generiaized and combine them with lmb.
>
> But then this would require some sort of handling of 'user does not need DMA[32]
> memory, so avoid it' and 'user can only use DMA[32] memory' in the early_res
> allocator as well.
>
> I ask this specifically because you move this fix into the bootmem compatibility
> code while there is not yet a way to tell early_res the same thing, so switching
> a user that _needs_ to specify this requirement from bootmem to early_res is not
> yet possible, is it?
just let caller set the 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;
>
> I think it would make sense to move the parameter check before doing the
> allocation. Then you save the second call.
I am trying to avoid the second call.
please check another patch about "introduce bootmem_default_goal : don't punish 64bit system without 4g ram"
>
> And a second nitpick: naming the inner function __foo and the outer one ___foo seems
> confusing to me. Could you maybe rename the wrapper? bootmem_compat_alloc_early() or
> something like that?
ok.
Thanks
Yinghai
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