On Wed, Oct 06, 2021 at 05:23:49PM +0200, David Hildenbrand wrote: > On 06.10.21 17:22, Al Viro wrote: > > On Wed, Oct 06, 2021 at 03:58:14PM +0100, Matthew Wilcox wrote: > > > David expressed some unease about the lack of typesafety in patches > > > 1 & 2 of the page->slab conversion [1], and I'll admit to not being > > > particularly a fan of passing around an unsigned long. That crystallised > > > in a discussion with Kent [2] about how to lock a page when you don't know > > > its type (solution: every memory descriptor type starts with a > > > pgflags_t) > > > > Why bother making it a struct? What's wrong with __bitwise and letting > > sparse catch conversions? > > > > As I raised in my reply, we store all kinds of different things in > page->flags ... not sure if that could be worked around somehow. What of that? Inline helpers with force-casts for accessing those and that's it... Use of __bitwise is simply invisible to compiler - it doesn't get past the preprocessor on non-sparse builds. So it's not like you'd disrupt the atomic accesses, layout, etc.
