Re: low-memory crash with patch "capture a page under direct compaction"

[Qian Cai <cai@xxxxxx>]

I don't understand this part.

@@ -2279,14 +2286,24 @@ static enum compact_result compact_zone_order(struct
zone *zone, int order,
                .ignore_skip_hint = (prio == MIN_COMPACT_PRIORITY),
                .ignore_block_suitable = (prio == MIN_COMPACT_PRIORITY)
        };
+       struct capture_control capc = {
+               .cc = &cc,
+               .page = NULL,
+       };
+
+       if (capture)
+               current->capture_control = &capc;


That check will always be true as it is,

struct page **capture;

*capture could be NULL, but not capture because in
__alloc_pages_direct_compact(), it does,

struct page *page = NULL;
capture = &page;