Add malloc_domainset_aligned(9) and use it in x86 busdma bounce.

[andrew]

sys/x86/x86/busdma_bounce.c

450–451

We'll need a check that the alignment isn't too large for malloc_domainset_aligned.

[kib]

sys/x86/x86/busdma_bounce.c

450–451

There is KASSERT() in malloc_aligned, and I really do not expect small allocations (less than page size) to request large alignment.

Another issue is that there is no way to report the alignment limits, except perhaps adding a function to return just the limit.

[markj]

sys/kern/kern_malloc.c

776

I would add an assertion that the result really is correctly aligned.

[kib]

Improve asserts.

[kib]

Assert that malloc result is single-page. Otherwise it cannot be loaded.

[andrew]

sys/x86/x86/busdma_bounce.c

436

This comment needs to be updated.

[kib]

Update comment.

[kib]

Fix types in casts.

[pho]

I tested D28147.82306.diff on i386 for 8 hours and on amd64 for 47 hours. No problems seen.