Re: [PATCH RFC] mm/readahead: Fix repeat initial_readahead

[zippermonkey <zzippermonkey@outlook.com>]

To illustrate this problem, I created the following example:


Assuming that the process reads sequentially from the beginning of the 
file and
calls the `page_cache_sync_readahead` function. In this sync readahead 
function,
since the index is 0, it will proceed to `initial_readahead` and initialize
`ra_state`. It allocates a folio with an order of 2 and marks it as 
PG_readahead.
Next, because` (folio_test_readahead(folio))` is true, the 
page_cache_async_ra
function is called, which causes the `ra_state` to be initialized again.