Re: [PATCH] mm/fadvise: avoid remote LRU drain for mapped folio failures

[Andrew Morton]

On Wed,  6 May 2026 11:23:59 +0000 fujunjie <fujunjie1@xxxxxx> wrote:

> generic_fadvise(POSIX_FADV_DONTNEED) drains the local LRU batch and
> then tries to invalidate the requested page-cache range. If any folio
> could not be evicted, it assumes that a remote per-cpu LRU batch might
> be pinning the folio, calls lru_add_drain_all(), and walks the mapping
> again.
> 
> ...
> 
> Teach the folio eviction path to report whether a failure hit the
> existing refcount check on a clean, unmapped folio. Only request the
> global drain for that case. This preserves the existing fallback for
> failures that a remote LRU drain can plausibly fix, while avoiding it
> for failure reasons that a remote drain is not expected to resolve.
> 

Thanks.  AI reviw asked one question:
	https://sashiko.dev/#/patchset/tencent_DEDC345B4071ED3C9B293ACD437B9C8DBC0A@xxxxxx