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Index: vm_phys.c
===================================================================
--- vm_phys.c
+++ vm_phys.c
@@ -1095,14 +1095,38 @@
}
/*
- * Free a contiguous, arbitrarily sized set of physical pages.
+ * Return the largest possible order of a page starting at m.
+ */
+static int
+max_order(vm_page_t m)
+{
+ /*
+ * Unsigned "min" is used here so that "order" is assigned
+ * "VM_NFREEORDER - 1" when "m"'s physical address is zero
+ * or the low-order bits of its physical address are zero
+ * because the size of a physical address exceeds the size of
+ * a long.
+ */
+ return (min(ffsl(VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT) - 1,
+ VM_NFREEORDER - 1));
+}
+
+/*
+ * Free a contiguous, arbitrarily sized set of physical pages,
+ * without block merging.
*
+ * The pages just before and after the freed pages must be
+ * allocated, because there is no check here for buddy-
+ * system merges.
+ *
* The free page queues must be locked.
*/
-void
-vm_phys_free_contig(vm_page_t m, u_long npages)
+static void
+vm_phys_nomerge_free_contig(vm_page_t m, u_long npages)
{
- u_int n;
+ struct vm_freelist *fl;
+ struct vm_phys_seg *seg;
+ vm_page_t m_end;
int order;
/*
@@ -1110,32 +1134,62 @@
* possible power-of-two-sized subsets.
*/
vm_domain_free_assert_locked(vm_pagequeue_domain(m));
- for (;; npages -= n) {
- /*
- * Unsigned "min" is used here so that "order" is assigned
- * "VM_NFREEORDER - 1" when "m"'s physical address is zero
- * or the low-order bits of its physical address are zero
- * because the size of a physical address exceeds the size of
- * a long.
- */
- order = min(ffsl(VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT) - 1,
- VM_NFREEORDER - 1);
- n = 1 << order;
- if (npages < n)
- break;
- vm_phys_free_pages(m, order);
- m += n;
+ seg = &vm_phys_segs[m->segind];
+ fl = (*seg->free_queues)[m->pool];
+ m_end = m + npages;
+ /* Free blocks of increasing size. */
+ while ((order = max_order(m)) < VM_NFREEORDER - 1 &&
+ m + (1 << order) <= m_end) {
+ vm_freelist_add(fl, m, order, 1);
+ m += (1 << order);
}
- /* The residual "npages" is less than "1 << (VM_NFREEORDER - 1)". */
- for (; npages > 0; npages -= n) {
- order = flsl(npages) - 1;
- n = 1 << order;
- vm_phys_free_pages(m, order);
- m += n;
+ /* Free blocks of maximum size. */
+ while (m + (1 << order) <= m_end) {
+ vm_freelist_add(fl, m, order, 1);
+ m += (1 << order);
}
+ /* Free blocks of diminishing size. */
+ while (m < m_end) {
+ order = flsl(m_end - m) - 1;
+ vm_freelist_add(fl, m, order, 1);
+ m += (1 << order);
+ }
}
/*
+ * Free a contiguous, arbitrarily sized set of physical pages.
+ *
+ * The free page queues must be locked.
+ */
+void
+vm_phys_free_contig(vm_page_t m, u_long npages)
+{
+ int order_start, order_end;
+ vm_page_t m_start, m_end;
+
+ vm_domain_free_assert_locked(vm_pagequeue_domain(m));
+
+ m_start = m;
+ order_start = max_order(m_start);
+ if (order_start < VM_NFREEORDER - 1)
+ m_start += 1 << order_start;
+ m_end = m + npages;
+ order_end = max_order(m_end);
+ if (order_end < VM_NFREEORDER - 1)
+ m_end -= 1 << order_end;
+ /*
+ * Avoid unnecessary coalescing by freeing the pages at the start and
+ * end of the range last.
+ */
+ if (m_start < m_end)
+ vm_phys_nomerge_free_contig(m_start, m_end - m_start);
+ if (order_start < VM_NFREEORDER - 1)
+ vm_phys_free_pages(m, order_start);
+ if (order_end < VM_NFREEORDER - 1)
+ vm_phys_free_pages(m_end, order_end);
+}
+
+/*
* Scan physical memory between the specified addresses "low" and "high" for a
* run of contiguous physical pages that satisfy the specified conditions, and
* return the lowest page in the run. The specified "alignment" determines

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