Re: [PATCH 6.12.y] mm/damon/ops-common: putback folios on invalid migrate nid

[sashiko-bot@kernel.org]

> From: liyouhong <liyouhong@kylinos.cn>
> 
> damon_pa_migrate() and damos_va_migrate() isolate folios into a local list
> and then call damon_migrate_pages().  When target_nid is invalid
> (including the scheme default NUMA_NO_NODE / -1), damon_migrate_pages()
> returns early without putting the folios back to the LRU.
> 
> Callers then discard the list head while those folios remain isolated with
> an extra reference taken by folio_isolate_lru().  The pages stay off the
> LRU for as long as the mapping exists (anon active+inactive counts drop
> while RSS does not), and the leftover references can pin the pages after
> the mapping is gone.
> 
> Put the folios back on the invalid-nid path so ignored migration requests
> still return them to the LRU.
> 
> Link: https://lore.kernel.org/20260726014815.1280757-1-dayou5941@163.com
> Fixes: 7e6c3130690a ("mm/damon/ops-common: ignore migration request to invalid nodes")
> Assisted-by: Cursor:grok-4.5
> Reviewed-by: SJ Park <sj@kernel.org>
> Signed-off-by: liyouhong <liyouhong@kylinos.cn>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> (cherry picked from commit 5deb65c34e682e7c5f5df417a70e223e8fcc5f5a)
> Signed-off-by: SJ Park <sj@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

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