mm/page_owner: add MR_NEVER to enum migrate_reason and use it for last_migrate_reason

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The last_migrate_reason field uses -1 as a sentinel value to mean "no
migration has happened".  Replace the four bare -1 occurrences by adding a
proper MR_NEVER member to enum migrate_reason, defining a corresponding
"never_migrated" string in the MIGRATE_REASON trace macro, and updating
the GDB page_owner script to use MR_NEVER instead of the hardcoded -1 so
that lx-dump-page-owner does not incorrectly report unmigrated pages as
migrated.

No functional change.

Link: https://lore.kernel.org/20260714015117.78351-3-ye.liu@linux.dev
Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

...

This commit is contained in:

Ye Liu 2026-07-14 09:51:01 +08:00 • committed by Andrew Morton

parent 53472eb262

commit 7eeed888c9

4 changed files with 10 additions and 6 deletions

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1

include/linux/migrate_mode.h

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3

include/trace/events/migrate.h

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8

mm/page_owner.c

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4

scripts/gdb/linux/page_owner.py

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