[PATCH RFC v3 1/7] mm: memory_failure: Clarify the MF_DELAYED definition

[Lisa Wang]

This patch clarifies the definition of MF_DELAYED to represent cases
where a folio's removal is initiated but not immediately completed
(e.g., due to remaining metadata references).

Signed-off-by: Lisa Wang <wyihan@xxxxxxxxxx>
---
 mm/memory-failure.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ee42d4361309..2e53b3024391 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -849,24 +849,25 @@ static int kill_accessing_process(struct task_struct *p, unsigned long pfn,
 }
 
 /*
- * MF_IGNORED - The m-f() handler marks the page as PG_hwpoisoned'ed.
+ * MF_IGNORED - The m-f() handler marks the page as PG_hwpoison'ed.
  * But it could not do more to isolate the page from being accessed again,
  * nor does it kill the process. This is extremely rare and one of the
  * potential causes is that the page state has been changed due to
  * underlying race condition. This is the most severe outcomes.
  *
- * MF_FAILED - The m-f() handler marks the page as PG_hwpoisoned'ed.
+ * MF_FAILED - The m-f() handler marks the page as PG_hwpoison'ed.
  * It should have killed the process, but it can't isolate the page,
  * due to conditions such as extra pin, unmap failure, etc. Accessing
  * the page again may trigger another MCE and the process will be killed
  * by the m-f() handler immediately.
  *
- * MF_DELAYED - The m-f() handler marks the page as PG_hwpoisoned'ed.
- * The page is unmapped, and is removed from the LRU or file mapping.
- * An attempt to access the page again will trigger page fault and the
- * PF handler will kill the process.
+ * MF_DELAYED - The m-f() handler marks the page as PG_hwpoison'ed.
+ * It means the page was unmapped and partially isolated (e.g. removed from
+ * file mapping or the LRU) but full cleanup is deferred (e.g. the metadata
+ * for the memory, as in struct page/folio, is still referenced). Any
+ * further access to the page will result in the process being killed.
  *
- * MF_RECOVERED - The m-f() handler marks the page as PG_hwpoisoned'ed.
+ * MF_RECOVERED - The m-f() handler marks the page as PG_hwpoison'ed.
  * The page has been completely isolated, that is, unmapped, taken out of
  * the buddy system, or hole-punched out of the file mapping.
  */

-- 
2.53.0.1213.gd9a14994de-goog