On Tue, Jul 13, 2021 at 06:56:28PM -0700, Andrew Morton wrote: > On Tue, 13 Jul 2021 11:55:04 -0400 Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > I agree that _is_ reads nicer by itself, but paired with other ops > > such as testset, _test_ might be better. > > > > For example, in __set_page_dirty_no_writeback() > > > > if (folio_is_dirty()) > > return !folio_testset_dirty() > > > > is less clear about what's going on than would be: > > > > if (folio_test_dirty()) > > return !folio_testset_dirty() > > I like folio_is_foo(). As long as it is used consistently, we'll get > used to it quickly. I'm not sure that folio_is_private(), folio_is_lru(), folio_is_waiters(), or folio_is_reclaim() really work. > Some GNU tools are careful about appending "_p" to > functions-which-test-something (stands for "predicate"). Having spent > a lot of time a long time ago with my nose in this stuff, I found the > convention to be very useful. I think foo_is_bar() is as good as > foo_bar_p() in this regard. I just wish C let us put '?' on the end of a function name, but I recognise the ambiguity with foo?bar:baz; > And sure, the CaMeLcAsE is fugly, but it sure is useful. > set_page_dirty() is very different from SetPageDirty() and boy that > visual differentiation is a relief. Oh, I'm glad you brought that up </sarcasm> In folios, here's how that ends up looking: SetPageDirty() -> folio_set_dirty_flag() (johannes proposes folio_set_dirty instead) set_page_dirty() -> folio_mark_dirty() aops->set_page_dirty() -> aops->dirty_folio() __set_page_dirty() -> __folio_mark_dirty() __set_page_dirty_buffers() -> block_dirty_folio() __set_page_dirty_nobuffers() -> filemap_dirty_folio() __set_page_dirty_no_writeback() -> dirty_folio_no_writeback() I kind of feel that last one should be nowb_dirty_folio(), but I'm also hoping to eliminate it; if the filesystem sets AS_NO_WRITEBACK_TAGS in mapping->flags, then we just inline the no-writeback case into folio_mark_dirty() (which already has it for the !mapping case).
