Messages in this thread | | | Date | Tue, 22 Apr 2008 13:22:13 -0500 | From | Robin Holt <> | Subject | Re: [PATCH 00 of 12] mmu notifier #v13 |
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I believe the differences between your patch set and Christoph's need to be understood and a compromise approach agreed upon.
Those differences, as I understand them, are:
1) invalidate_page: You retain an invalidate_page() callout. I believe we have progressed that discussion to the point that it requires some direction for Andrew, Linus, or somebody in authority. The basics of the difference distill down to no expected significant performance difference between the two. The invalidate_page() callout potentially can simplify GRU code. It does provide a more complex api for the users of mmu_notifier which, IIRC, Christoph had interpretted from one of Andrew's earlier comments as being undesirable. I vaguely recall that sentiment as having been expressed.
2) Range callout names: Your range callouts are invalidate_range_start and invalidate_range_end whereas Christoph's are start and end. I do not believe this has been discussed in great detail. I know I have expressed a preference for your names. I admit to having failed to follow up on this issue. I certainly believe we could come to an agreement quickly if pressed.
3) The structure of the patch set: Christoph's upcoming release orders the patches so the prerequisite patches are seperately reviewable and each file is only touched by a single patch. Additionally, that allows mmu_notifiers to be introduced as a single patch with sleeping functionality from its inception and an API which remains unchanged. Your patch set, however, introduces one API, then turns around and changes that API. Again, the desire to make it an unchanging API was expressed by, IIRC, Andrew. This does represent a risk to XPMEM as the non-sleeping API may become entrenched and make acceptance of the sleeping version less acceptable.
Can we agree upon this list of issues?
Thank you, Robin Holt
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