On 2022/9/2 17:04, David Hildenbrand wrote:
On 02.09.22 11:02, Kefeng Wang wrote:
On 2022/9/2 16:42, David Hildenbrand wrote:
On 02.09.22 08:47, Kefeng Wang wrote:
Add pageblock_aligned() and use it to simplify code.
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
[...]
- unsigned long nr_pgmask = pageblock_nr_pages - 1;
int nid = zone_to_nid(zone);
unsigned long nr_pages = 0;
int zid = zone_idx(zone);
@@ -1977,7 +1974,7 @@ static unsigned long __init deferred_init_pages(struct zone *zone,
if (!deferred_pfn_valid(pfn)) {
page = NULL;
continue;
- } else if (!page || !(pfn & nr_pgmask)) {
I didn't sleep too well this night and am tired, please tell me why I'm
wrong :)
Wish you have a good reset :)
Thanks, the headache isn't helping :D
"pfn & (pageblock_nr_pages - 1)" is true if the pageblock is not aligned
E.g., pfn = 1, pageblock_nr_pages = 512
pfn & (pageblock_nr_pages - 1)
-> 1 & (512 - 1)
-> 1 & 511
-> true
"!(pfn & (pageblock_nr_pages - 1))" is true if the pageblock is aligned
-> !(true)
-> false
However, "!pageblock_aligned(1)" = true
+ } else if (!page || !pageblock_aligned(pfn)) {
pageblock_aligned(pfn) IS_ALIGNED((unsigned long)(pfn), pageblock_nr_pages)
#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) (((pfn) &
(pageblock_nr_pages - 1)) == 0) -> ((1 & 512 -1) == 0) -> ((1 & 511) ==
0) -> ((511) == 0) -> false
right ?
yes ... and inverting that would give you "true", which is not what we want?
oops... it's my fault, looks like I need to have a reset to save my
brain...
Again, sorry if I'm wrong ...
