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vm_phys: tune vm_phys_enqueue_contig loop

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Rewrite the final loop in vm_phys_enqueue_contig as a new function,
vm_phys_enq_beg, to reduce amd64 code size.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D41289
This commit is contained in:
Doug Moore 2023-08-04 21:09:39 -05:00
parent dedc71fd38
commit e77f4e7f59
1 changed files with 36 additions and 8 deletions
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44
sys/vm/vm_phys.c
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@ -680,6 +680,41 @@ vm_phys_split_pages(vm_page_t m, int oind, struct vm_freelist *fl, int order,
}
}
/*
* Add the physical pages [m, m + npages) at the beginning of a power-of-two
* aligned and sized set to the specified free list.
*
* When this function is called by a page allocation function, the caller
* should request insertion at the head unless the lower-order queues are
* known to be empty. The objective being to reduce the likelihood of long-
* term fragmentation by promoting contemporaneous allocation and (hopefully)
* deallocation.
*
* The physical page m's buddy must not be free.
*/
static void
vm_phys_enq_beg(vm_page_t m, u_int npages, struct vm_freelist *fl, int tail)
{
int order;
KASSERT(npages == 0 ||
(VM_PAGE_TO_PHYS(m) &
((PAGE_SIZE << (fls(npages) - 1)) - 1)) == 0,
("%s: page %p and npages %u are misaligned",
__func__, m, npages));
while (npages > 0) {
KASSERT(m->order == VM_NFREEORDER,
("%s: page %p has unexpected order %d",
__func__, m, m->order));
order = fls(npages) - 1;
KASSERT(order < VM_NFREEORDER,
("%s: order %d is out of range", __func__, order));
vm_freelist_add(fl, m, order, tail);
m += 1 << order;
npages -= 1 << order;
}
}
/*
* Add the physical pages [m, m + npages) at the end of a power-of-two aligned
* and sized set to the specified free list.
@ -1190,14 +1225,7 @@ vm_phys_enqueue_contig(vm_page_t m, u_long npages)
m += 1 << order;
}
/* Free blocks of diminishing size. */
while (m < m_end) {
KASSERT(seg == &vm_phys_segs[m->segind],
("%s: page range [%p,%p) spans multiple segments",
__func__, m_end - npages, m));
order = flsl(m_end - m) - 1;
vm_freelist_add(fl, m, order, 1);
m += 1 << order;
}
vm_phys_enq_beg(m, m_end - m, fl, 1);
}
/*