PAE adds another level to the i386 page table. This level is a small

4-entry table that must be located within the first 4GB of RAM.  This
requirement is met by defining an UMA zone with a custom back-end
allocator function.  This revision makes two changes to this back-end
allocator function: (1) It replaces the use of contigmalloc() with the
use of kmem_alloc_contig().  This eliminates "double accounting", i.e.,
accounting by both the UMA zone and malloc tags.  (I made the same
change for the same reason to the zones supporting jumbo frames a week
ago.) (2) It passes through the "wait" parameter, i.e., M_WAITOK,
M_ZERO, etc. to kmem_alloc_contig() rather than ignoring it.
pmap_init() calls uma_zalloc() with both M_WAITOK and M_ZERO.  At the
moment, this is harmless only because the default behavior of
contigmalloc()/kmem_alloc_contig() is to wait and because pmap_init()
doesn't really depend on the memory being zeroed.

The back-end allocator function in the Xen pmap is dead code.  I am
changing it nonetheless because I don't want to leave any "bad examples"
in the source tree for someone to copy at a later date.

Approved by:	re (kib)

1 files changed, 5 insertions, 6 deletions

diff --git a/sys/i386/xen/pmap.c b/sys/i386/xen/pmap.c
index 59947e8..ed4300f 100644
--- a/sys/i386/xen/pmap.c
+++ b/sys/i386/xen/pmap.c
@@ -608,15 +608,14 @@ pmap_page_init(vm_page_t m)
 }
 
 #if defined(PAE) && !defined(XEN)
-
-static MALLOC_DEFINE(M_PMAPPDPT, "pmap", "pmap pdpt");
-
 static void *
 pmap_pdpt_allocf(uma_zone_t zone, int bytes, u_int8_t *flags, int wait)
 {
-	*flags = UMA_SLAB_PRIV;
-	return (contigmalloc(PAGE_SIZE, M_PMAPPDPT, 0, 0x0ULL, 0xffffffffULL,
-	    1, 0));
+
+	/* Inform UMA that this allocator uses kernel_map/object. */
+	*flags = UMA_SLAB_KERNEL;
+	return ((void *)kmem_alloc_contig(kernel_map, bytes, wait, 0x0ULL,
+	    0xffffffffULL, 1, 0, VM_CACHE_DEFAULT));
 }
 #endif