For the particular bootmem node, the minimal and maximal PFN (
Page Frame Number) have been traced in the instance of "struct
bootmem_data_t". On current implementation, the maximal PFN isn't
checked while deallocating a bunch (BITS_PER_LONG) of page frames.
So the current implementation won't work if the maximal PFN isn't
aligned with BITS_PER_LONG.
The patch will check the maximal PFN of the given bootmem node.
Also, we needn't check all the bits map when the starting PFN isn't
BITS_PER_LONG aligned. Actually, we should start from the offset
of the bits map, which indicated by the starting PFN.
Signed-off-by: Gavin Shan <shangw@xxxxxxxxxxxxxxxxxx>
---
mm/bootmem.c | 11 ++++++++---
1 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/mm/bootmem.c b/mm/bootmem.c
index 5a04536..ebac3ba 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -194,16 +194,20 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
* BITS_PER_LONG block of pages in front of us, free
* it in one go.
*/
- if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) {
+ if (end - start >= BITS_PER_LONG &&
+ IS_ALIGNED(start, BITS_PER_LONG) &&
+ vec == ~0UL) {
int order = ilog2(BITS_PER_LONG);
__free_pages_bootmem(pfn_to_page(start), order);
count += BITS_PER_LONG;
start += BITS_PER_LONG;
} else {
- unsigned long off = 0;
+ unsigned long cursor = start;
+ unsigned long off = cursor & (BITS_PER_LONG - 1);
- while (vec && off < BITS_PER_LONG) {
+ vec >>= off;
+ while (vec && off < BITS_PER_LONG && cursor < end) {
if (vec & 1) {
page = pfn_to_page(start + off);
__free_pages_bootmem(page, 0);
@@ -211,6 +215,7 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
}
vec >>= 1;
off++;
+ cursor++;
}
start = ALIGN(start + 1, BITS_PER_LONG);
}
--
1.7.5.4
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