On 11/8/24 12:25 PM, Kirill A. Shutemov wrote: > On Fri, Nov 08, 2024 at 10:43:26AM -0700, Jens Axboe wrote: >> Add a page flag that file IO can use to indicate that the IO being done >> is uncached, as in it should not persist in the page cache after the IO >> has been completed. > > Flag bits are precious resource. It would be nice to re-use an existing > bit if possible. I knoew, like I mentioned in the reply to willy, I knew this one would be an interesting discussion in and of itself. > PG_reclaim description looks suspiciously close to what you want. > I wounder if it would be valid to re-define PG_reclaim behaviour to drop > the page after writeback instead of moving to the tail of inactive list. You're the mm expert - I added the flag since then it has a clearly defined meaning, and I would not need to worry about any kind of odd overlap in paths I didn't know about. Would definitely entertain reusing something else, but I'll leave that in the hands of the people that know this code and the various intricacies and assumptions a lot better than I do. -- Jens Axboe
