| From | David Howells <> | Subject | Re: [PATCH net-next 03/12] mm: Make the page_frag_cache allocator alignment param a pow-of-2 | Date | Fri, 16 Jun 2023 16:28:29 +0100 |
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Alexander H Duyck <alexander.duyck@gmail.com> wrote:
> The requirement should only be cache alignment, not power of 2 > alignment.
Sure, but, upstream, page_frag_alloc_align() allows the specification of an alignment and applies that alignment by:
offset &= align_mask;
which doesn't really make sense unless the alignment boils down to being a power of two. Now, it might make sense to kill off the align_mask parameter and just go with SMP_CACHE_BYTES (which will be a power of two).
Note, though, that most users seem to use an align_mask of ~0u which feels a bit dodgy (it's not an unsigned long), but is probably fine.
David
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