Hello,
On 06/27/2010 07:06 AM, David Rientjes wrote:
> On Fri, 25 Jun 2010, Christoph Lameter wrote:
>
>> In pcpu_alloc_info()
>
> You mean pcpu_build_alloc_info()?
Yeap.
>> @@ -105,7 +105,7 @@ extern struct pcpu_alloc_info * __init p
>> extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
>>
>> extern struct pcpu_alloc_info * __init pcpu_build_alloc_info(
>> - size_t reserved_size, ssize_t dyn_size,
>> + size_t reserved_size, size_t dyn_size,
>> size_t atom_size,
>> pcpu_fc_cpu_distance_fn_t cpu_distance_fn);
>>
>
> This can just be removed entirely, it's unnecessarily global.
Oh yeah, it's not used outside mm/percpu.c anymore. I'll make it
static.
>> /**
>> * pcpu_alloc_alloc_info - allocate percpu allocation info
>> * @nr_groups: the number of groups
>> @@ -1060,7 +1046,7 @@ void __init pcpu_free_alloc_info(struct
>> /**
>> * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
>> * @reserved_size: the size of reserved percpu area in bytes
>> - * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
>> + * @dyn_size: free size for dynamic allocation in bytes
>
> It's the minimum free size, it's not necessarily the exact size due to
> round-up.
Will update.
>> struct pcpu_alloc_info * __init pcpu_build_alloc_info(
>> - size_t reserved_size, ssize_t dyn_size,
>> + size_t reserved_size, size_t dyn_size,
>> size_t atom_size,
>> pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
>> {
>> @@ -1098,13 +1084,15 @@ struct pcpu_alloc_info * __init pcpu_bui
>> memset(group_map, 0, sizeof(group_map));
>> memset(group_cnt, 0, sizeof(group_map));
>>
>> + size_sum = PFN_ALIGN(static_size + reserved_size + dyn_size);
>> + dyn_size = size_sum - static_size - reserved_size;
>
> Ok, so the only purpose of "dyn_size" is to store in the struct
> pcpu_alloc_info later. Before this patch, ai->dyn_size would always be 0
> if that's what was passed to pcpu_build_alloc_info(), but due to this
> arithmetic it now requires that static_size + reserved_size to be pfn
> aligned. Where is that enforced or do we not care?
I'm not really following you, but
* Nobody called pcpu_build_alloc_info() w/ zero dyn_size. It was
either -1 or positive minimum size.
* None of static_size, reserved_size or dyn_size needs to be page
aligned.
Thanks for the review.
--
tejun
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