For debugging purposes it might be useful to keep the owner info even after page has been freed, and include it in e.g. dump_page() when detecting a bad page state. For that, change the PAGE_EXT_OWNER flag meaning to "page owner info has been set at least once" and add new PAGE_EXT_OWNER_ACTIVE for tracking whether page is supposed to be currently tracked allocated or free. Adjust dump_page() accordingly, distinguishing free and allocated pages. In the page_owner debugfs file, keep printing only allocated pages so that existing scripts are not confused, and also because free pages are irrelevant for the memory statistics or leak detection that's the typical use case of the file, anyway.
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| @@ -18,6 +18,7 @@ struct page_ext_operations { · 17 unmodified lines | |||
| 18 | 18 | ||
| 19 | enum page_ext_flags { | 19 | enum page_ext_flags { |
| 20 | PAGE_EXT_OWNER, | 20 | PAGE_EXT_OWNER, |
| 21 | PAGE_EXT_OWNER_ACTIVE, | ||
| 21 | #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) | 22 | #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) |
| 22 | PAGE_EXT_YOUNG, | 23 | PAGE_EXT_YOUNG, |
| 23 | PAGE_EXT_IDLE, | 24 | PAGE_EXT_IDLE, |