Re: [RFC PATCH -v3 1/2] lmb: seperate region array from lmb_region struct

Yinghai Lu
2010-03-24T05:48:02Z

On 03/23/2010 09:45 PM, Benjamin Herrenschmidt wrote:
> On Tue, 2010-03-23 at 11:42 +0100, Ingo Molnar wrote:
>> * Yinghai Lu <yinghai@kernel.org> wrote:
>>
>>> void __init lmb_init(void)
>>> {
>>> + lmb.memory.region = lmb_memory_region;
>>> + lmb.memory.region_array_size = ARRAY_SIZE(lmb_memory_region);
>>> + lmb.reserved.region = lmb_reserved_region;
>>> + lmb.reserved.region_array_size = ARRAY_SIZE(lmb_reserved_region);
>>> +
>>
>> That's rather unreadable and has random whitespace noise.
>>
>> Should be something like:
>>
>> lmb.memory.region = lmb_memory_region;
>> lmb.memory.region_array_size = ARRAY_SIZE(lmb_memory_region);
>> lmb.reserved.region = lmb_reserved_region;
>> lmb.reserved.region_array_size = ARRAY_SIZE(lmb_reserved_region);
>>
>> also, i'd suggest to shorten region_array_size to region_size (we know it's an
>> array), so it would become:
>
> I dislike those arrays anyways. See my other message about turning them
> into lists, which would get rid of capacity constraints completely. What
> do you think ?
>
2/2 introduce one new function that could double the array size

please check the v4.

the function rely on find_lmb_area().

it will check if there is enough space left, otherwise try to get new big array, and
copy old array to new array.

final function like:

static void __init __check_and_double_region_array(struct lmb_region *type,
struct lmb_property *static_region,
u64 ex_start, u64 ex_end)
{
u64 start, end, size, mem;
struct lmb_property *new, *old;
unsigned long rgnsz = type->nr_regions;

/* do we have enough slots left ? */
if ((rgnsz - type->cnt) > max_t(unsigned long, rgnsz/8, 2))
return;

old = type->region;
/* double it */
mem = -1ULL;
size = sizeof(struct lmb_property) * rgnsz * 2;
if (old == static_region)
start = 0;
else
start = __pa(old) + sizeof(struct lmb_property) * rgnsz;
end = ex_start;
if (start + size < end)
mem = find_lmb_area(start, end, size,
sizeof(struct lmb_property));
if (mem == -1ULL) {
start = ex_end;
end = get_max_mapped();
if (start + size < end)
mem = find_lmb_area(start, end, size, sizeof(struct lmb_property));
}
if (mem == -1ULL)
panic("can not find more space for lmb.reserved.region array");

new = __va(mem);
/* copy old to new */
memcpy(&new[0], &old[0], sizeof(struct lmb_property) * rgnsz);
memset(&new[rgnsz], 0, sizeof(struct lmb_property) * rgnsz);

memset(&old[0], 0, sizeof(struct lmb_property) * rgnsz);
type->region = new;
type->nr_regions = rgnsz * 2;
printk(KERN_DEBUG "lmb.reserved.region array is doubled to %ld at [%llx - %llx]\n",
type->nr_regions, mem, mem + size - 1);

/* reserve new array and free old one */
lmb_reserve(mem, sizeof(struct lmb_property) * rgnsz * 2);
if (old != static_region)
lmb_free(__pa(old), sizeof(struct lmb_property) * rgnsz);
}

void __init add_lmb_memory(u64 start, u64 end)
{
__check_and_double_region_array(&lmb.memory, &lmb_memory_region[0], start, end);
lmb_add(start, end - start);
}

void __init reserve_early(u64 start, u64 end, char *name)
{
if (start == end)
return;

if (WARN_ONCE(start > end, "reserve_early: wrong range [%#llx, %#llx]\n", start, end))
return;

__check_and_double_region_array(&lmb.reserved, &lmb_reserved_region[0], start, end);
lmb_reserve(start, end - start);
}

void __init free_early(u64 start, u64 end)
{
if (start == end)
return;

if (WARN_ONCE(start > end, "free_early: wrong range [%#llx, %#llx]\n", start, end))
return;

/* keep punching hole, could run out of slots too */
__check_and_double_region_array(&lmb.reserved, &lmb_reserved_region[0], start, end);
lmb_free(start, end - start);
}

with those function, we can replace the bootmem in x86.

Thanks

Yinghai