Messages in this thread | | | Date | Tue, 2 Feb 2021 15:38:59 -0500 | From | Peter Xu <> | Subject | Re: [PATCH] userfaultfd: hugetlbfs: only compile UFFD helpers if config enabled |
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On Tue, Feb 02, 2021 at 12:31:27PM -0800, Axel Rasmussen wrote: > For background, mm/userfaultfd.c provides a general mcopy_atomic > implementation. But some types of memory (e.g., hugetlb and shmem) need > a slightly different implementation, so they provide their own helpers > for this. In other words, userfaultfd is the only caller of this > function. > > This patch achieves two things: > > 1. Don't spend time compiling code which will end up never being > referenced anyway (a small build time optimization). > > 2. In future patches (e.g. [1]), we plan to extend the signature of > these helpers with UFFD-specific state (e.g., enums or structs defined > conditionally in userfaultfd_k.h). Once this happens, this patch will be > needed to avoid build errors (or, we'd need to define more UFFD-only > stuff unconditionally, which seems messier to me). > > Peter Xu suggested this be sent as a standalone patch, in the mailing > list discussion for [1]. > > [1] https://patchwork.kernel.org/project/linux-mm/list/?series=424091 > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
I meant a standalone patch along with the next version of your series would be good enough... :) If Mike is fine I won't complain if you'd squashed it into that patch either. The patch itself looks correct to me.
Reviewed-by: Peter Xu <peterx@redhat.com>
Thanks,
-- Peter Xu
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