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Index: sys/vm/memguard.c
===================================================================
--- sys/vm/memguard.c
+++ sys/vm/memguard.c
@@ -64,6 +64,13 @@
#include <vm/uma_int.h>
#include <vm/memguard.h>
+#if VM_NRESERVLEVEL > 0
+#define MEMGUARD_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT)
+#else
+#define MEMGUARD_SHIFT PAGE_SHIFT
+#endif
+#define MEMGUARD_ALIGN (1 << MEMGUARD_SHIFT)
+
static SYSCTL_NODE(_vm, OID_AUTO, memguard, CTLFLAG_RW, NULL, "MemGuard data");
/*
* The vm_memguard_divisor variable controls how much of kernel_arena should be
@@ -194,6 +201,7 @@
memguard_mapsize = mem_pgs * 2 * PAGE_SIZE;
if (km_size + memguard_mapsize > parent_size)
memguard_mapsize = 0;
+ memguard_mapsize = roundup2(memguard_mapsize, MEMGUARD_ALIGN);
return (km_size + memguard_mapsize);
}
@@ -206,7 +214,8 @@
{
vm_offset_t base;
- vmem_alloc(parent, memguard_mapsize, M_BESTFIT | M_WAITOK, &base);
+ vmem_xalloc(parent, memguard_mapsize, MEMGUARD_ALIGN, 0, 0,
+ VMEM_ADDR_MIN, VMEM_ADDR_MAX, M_BESTFIT | M_WAITOK, &base);
vmem_init(memguard_arena, "memguard arena", base, memguard_mapsize,
PAGE_SIZE, 0, M_WAITOK);
memguard_cursor = base;
@@ -286,9 +295,10 @@
void *
memguard_alloc(unsigned long req_size, int flags)
{
- vm_offset_t addr, origaddr;
+ vm_offset_t addr, next, origaddr;
u_long size_p, size_v;
- int do_guard, rv;
+ int domain, rv;
+ bool do_guard;
size_p = round_page(req_size);
if (size_p == 0)
@@ -332,6 +342,7 @@
memguard_cursor, VMEM_ADDR_MAX,
M_BESTFIT | M_NOWAIT, &origaddr) == 0)
break;
+
/*
* The map has no space. This may be due to
* fragmentation, or because the cursor is near the
@@ -348,14 +359,38 @@
addr = origaddr;
if (do_guard)
addr += PAGE_SIZE;
- rv = kmem_back(kernel_object, addr, size_p, flags);
+
+ /*
+ * The kmem_* API uses per-domain vmem arenas to ensure that pages
+ * backing a large virtual page all come from the same domain. We must
+ * provide the same guarantee.
+ */
+ domain = 0;
+#if VM_NRESERVLEVEL > 0
+ if (vm_ndomains > 1)
+ domain = (addr >> MEMGUARD_SHIFT) % vm_ndomains;
+#endif
+ rv = kmem_back_domain(domain, kernel_object, addr, size_p, flags);
if (rv != KERN_SUCCESS) {
vmem_xfree(memguard_arena, origaddr, size_v);
memguard_fail_pgs++;
addr = (vm_offset_t)NULL;
+#if VM_NRESERVLEVEL > 0
+ /*
+ * Select a different domain for subsequent allocations by
+ * advancing the cursor to the next superpage boundary. This
+ * may be undone by the non-atomic cursor update following a
+ * concurrent successful allocation.
+ */
+ if (vm_ndomains > 1) {
+ next = roundup2(memguard_cursor, MEMGUARD_ALIGN);
+ (void)atomic_cmpset_long(&memguard_cursor,
+ memguard_cursor, next);
+ }
+#endif
goto out;
}
- memguard_cursor = addr + size_v;
+ memguard_cursor = origaddr + size_v;
*v2sizep(trunc_page(addr)) = req_size;
*v2sizev(trunc_page(addr)) = size_v;
memguard_succ++;

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