We have now successfully removed all of the uses of some of the PageFlags from the kernel, but there's nothing to stop somebody reintroducing them. By splitting out FOLIO_FLAGS from PAGEFLAGS, we can stop defining the old flags; and we do that in some of the later patches. After doing this, I realised that dump_page() was living dangerously; we could end up calling folio_test_foo() on a pointer which no longer pointed to a folio (as dump_page() is not necessarily called when the caller has a reference to the page). So I fixed that up. And then I realised that this was the key to making dump_page() take a const argument, which means we can constify the page flags testing, which means we can remove more cast-away-the-const bad code. And here's where I ended up. Matthew Wilcox (Oracle) (8): mm: Separate out FOLIO_FLAGS from PAGEFLAGS mm: Remove PageWaiters, PageSetWaiters and PageClearWaiters mm: Remove PageYoung and PageIdle definitions mm: Add __dump_folio() mm: Make dump_page() take a const argument mm: Constify testing page/folio flags mm: Constify more page/folio tests mm: Remove cast from page_to_nid() include/linux/mm.h | 6 +- include/linux/mmdebug.h | 2 +- include/linux/page-flags.h | 153 +++++++++++++++++++++---------------- mm/debug.c | 122 ++++++++++++++++------------- mm/hugetlb.c | 4 +- 5 files changed, 161 insertions(+), 126 deletions(-) -- 2.43.0
