Hi Johannes,
Could you take a look on this while you have available time?
Thanks,
Gavin
>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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