From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> If the page is already in cache, we don't set PageReadahead on it. Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx> --- mm/readahead.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/readahead.c b/mm/readahead.c index ae231a5312cb..73cb59ed5cff 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -195,9 +195,12 @@ void page_cache_readahead_unbounded(struct address_space *mapping, if (page && !xa_is_value(page)) { /* - * Page already present? Kick off the current batch of - * contiguous pages before continuing with the next - * batch. + * Page already present? Kick off the current batch + * of contiguous pages before continuing with the + * next batch. This page may be the one we would + * have intended to mark as Readahead, but we don't + * have a stable reference to this page, and it's + * not worth getting one just for that. */ read_pages(&rac, &page_pool, true); continue; -- 2.25.1