On 21.12.2023 16:23, Andrew Cooper wrote: > On 12/12/2023 5:04 pm, Jan Beulich wrote: >> On 24.11.2023 11:30, Oleksii Kurochko wrote: >>> The definition of __read_mostly should be removed in: >>> https://lore.kernel.org/xen-devel/f25eb5c9-7c14-6e23-8535-2c66772b3...@suse.com/ >> Andrew, can we settle on what to do with that patch? If you don't like me >> putting __read_mostly in xen/cache.h (consistent with __ro_after_init), >> would you please make an alternative suggestion? > > xen/linkage.h? xen/sections.h?
Well, that's the problem: There's no xen/sections.h (and I don't see why we'd introduce one just for this), and while xen/linkage.h is about to appear for the entry point annotations, I don't think it is a reasonable fit. Otoh with __ro_after_init ... > Sorry - I didn't mean to block it specifically, but I do think > xen/cache.h is the wrong place for both to live and that it's a small > enough change to warrant sorting out nicely once and for all. ... living in xen/cache.h already, __read_mostly is even more logical to put there than __ro_after_init. For the latter I agree the purpose isn't really cache related, while for the former it is. From your original reply to the patch submission, I have to admit I don't really understand what "micro-architectural" detail you mean: The goal of avoiding unnecessary cache line ping-pong doesn't look to be what you mean, as imo that's a valid (and generic) goal. And that's what I think is the reason the #define presently lives in asm/cache.h, justifying my moving of it to xen/cache.h. So if you can't get yourself to accept xen/cache.h as the new (even if only temporary) location, I think you can be expected to make a better proposal. With "better" there meaning you supplying a reason for why you think that placement is better than xen/cache.h. For example, if I knew what you expected xen/sections.h to further contain (in the long run), I might find myself agreeing to that. Yet other section annotation #define-s live elsewhere anyway, with - in particular - __init and friends imo not likely to move out of their present header (xen/init.h). Jan
