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Subject[PATCH 08/36] x86: dynamic increase early_res array size
use early_res_count to track the num, and use find_e820 to get new buffer.
and copy from old to new one.

also clear early_res to prevent later invalid using

-v2 _check_and_double_early_res should take new start

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
arch/x86/kernel/e820.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 53 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 291f6d2..949d688 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -908,6 +908,48 @@ void __init reserve_early_overlap_ok(u64 start, u64 end, char *name)
__reserve_early(start, end, name, 1);
}

+static void __init __check_and_double_early_res(u64 start)
+{
+ u64 end, size, mem;
+ struct early_res *new;
+
+ /* do we have enough slots left ? */
+ if ((max_early_res - early_res_count) > max(max_early_res/8, 2))
+ return;
+
+ /* double it */
+ end = max_pfn_mapped << PAGE_SHIFT;
+ size = sizeof(struct early_res) * max_early_res * 2;
+ mem = find_e820_area(start, end, size, sizeof(struct early_res));
+
+ if (mem == -1ULL)
+ panic("can not find more space for early_res array");
+
+ new = __va(mem);
+ /* save the first one for own */
+ new[0].start = mem;
+ new[0].end = mem + size;
+ new[0].overlap_ok = 0;
+ /* copy old to new */
+ if (early_res == early_res_x) {
+ memcpy(&new[1], &early_res[0],
+ sizeof(struct early_res) * max_early_res);
+ memset(&new[max_early_res+1], 0,
+ sizeof(struct early_res) * (max_early_res - 1));
+ early_res_count++;
+ } else {
+ memcpy(&new[1], &early_res[1],
+ sizeof(struct early_res) * (max_early_res - 1));
+ memset(&new[max_early_res], 0,
+ sizeof(struct early_res) * max_early_res);
+ }
+ memset(&early_res[0], 0, sizeof(struct early_res) * max_early_res);
+ early_res = new;
+ max_early_res *= 2;
+ printk(KERN_DEBUG "early_res array is doubled to %d at [%llx - %llx]\n",
+ max_early_res, mem, mem + size - 1);
+}
+
/*
* Most early reservations come here.
*
@@ -921,6 +963,8 @@ void __init reserve_early(u64 start, u64 end, char *name)
if (start >= end)
return;

+ __check_and_double_early_res(end);
+
drop_overlaps_that_are_ok(start, end);
__reserve_early(start, end, name, 0);
}
@@ -949,6 +993,10 @@ void __init early_res_to_bootmem(u64 start, u64 end)
for (i = 0; i < max_early_res && early_res[i].end; i++)
count++;

+ /* need to skip first one ?*/
+ if (early_res != early_res_x)
+ idx = 1;
+
printk(KERN_INFO "(%d/%d early reservations) ==> bootmem [%010llx - %010llx]\n",
count - idx, max_early_res, start, end);
for (i = idx; i < count; i++) {
@@ -966,6 +1014,11 @@ void __init early_res_to_bootmem(u64 start, u64 end)
reserve_bootmem_generic(final_start, final_end - final_start,
BOOTMEM_DEFAULT);
}
+ /* clear them */
+ memset(&early_res[0], 0, sizeof(struct early_res) * max_early_res);
+ early_res = NULL;
+ max_early_res = 0;
+ early_res_count = 0;
}

/* Check for already reserved areas */
--
1.6.4.2


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