[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [XEN PATCH][for-4.19 v4 1/8] xen/include: add macro ISOLATE_LOW_BIT
Hi Jan, While I've committed this patch (hoping that I got the necessary context adjustment right for the automation/eclair_analysis/ECLAIR/deviations.eclchange), I'd like to come back to this before going further with usersof the new macro: I still think we ought to try to get to the single evaluation wherever possible. The macro would then be used only in caseswhere the alternative construct (perhaps an isolate_lsb() macro, living perhaps in xen/bitops.h) cannot be used. ISOLATE_LSB() would then wantto gain a comment directing people to the "better" sibling. Thoughts?Having the users in place would help me estimate the remaining work that needs to be done on this rule and see if my local counts match up withthe counts in staging.By "having the users in place", you mean you want other patches in thisand the dependent series to be committed as-is (except for the name change)? That's what I'd like to avoid, as it would mean touching all those use sites again where the proposed isolate_lsb() could be used instead. I'd rather see all use sites be put into their final shape right away.This request is coming a bit late and also after all the patches have been reviewed already. I for one am not looking forward to review them again. That said, if you could be more specified maybe it could become actionable: - do you have a pseudo code implementation of the "better" macro you would like to propose?May I remind you that I made this request (including a draft implementation) before already, and Nicola then merely found that the evaluate-once form simply cannot be used everywhere? Anybody could have thought of the option of "splitting" the macro. After all I hope that there is no disagreement onmacro arguments better being evaluated just once, whenever possible.- do you have an list of call sites you would like to be changed to usethe "better" macro?No, I don't have a list. But the pattern is pretty clear: The "better" formought to be used wherever it actually can be used.Also, you might remember past discussions about time spent making changes yourself vs. others doing the same. This is one of those casesthat it would be faster for you to make the change and send a patch thanexplaining someone else how to do it, then review the result (and review it again as it probably won't be exactly as you asked the first time.)If you don't want the call sites to be changes twice, may I suggest you provide a patch on top of Nicola's series, I review and ack your patch,and Nicola or I rebase & resend the series so that the call sites are only changes once as you would like? I think that's going to be way faster.I'll see if I can find time to do so. I don't normally work on top ofother people's uncommitted patches, though ... So I may also choose to goa slightly different route. (You realize though that all still pending patches using the new macro need touching again anyway, don't you?) Jan Then perhaps it's best if I give it a try at doing the single evaluation macro, so that I can make a series modifying the call sites only once on top of that and send everything in one go. Before doing that, though, I'll make a thread where various aspects that are not so clear yet can be discussed, so that we can devise a robust solution (also to dig this out of this deep thread). -- Nicola Vetrini, BSc Software Engineer, BUGSENG srl (https://bugseng.com)
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