Constrain the buffer cache to use only the dma reachable region of memory.

With this change bufcachepercent will be the percentage of dma reachable
memory that the buffer cache will attempt to use.
ok deraadt@ thib@ oga@

1 files changed, 27 insertions, 1 deletions

diff --git a/sys/uvm/uvm_page.c b/sys/uvm/uvm_page.c
index 82951d1c99f..a431450748a 100644
--- a/sys/uvm/uvm_page.c
+++ b/sys/uvm/uvm_page.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_page.c,v 1.103 2011/04/02 12:38:37 ariane Exp $	*/
+/*	$OpenBSD: uvm_page.c,v 1.104 2011/04/02 16:47:17 beck Exp $	*/
 /*	$NetBSD: uvm_page.c,v 1.44 2000/11/27 08:40:04 chs Exp $	*/
 
 /* 
@@ -804,6 +804,32 @@ uvm_pagealloc_pg(struct vm_page *pg, struct uvm_object *obj, voff_t off,
 }
 
 /*
+ * interface used by the buffer cache to allocate a buffer at a time.
+ * The pages are allocated wired in DMA accessible memory
+ */
+void
+uvm_pagealloc_multi(struct uvm_object *obj, voff_t off, vsize_t size, int flags)
+{
+	struct pglist    plist;
+	struct vm_page  *pg;
+	int              i;
+
+
+	TAILQ_INIT(&plist);
+	(void) uvm_pglistalloc(size, dma_constraint.ucr_low,
+	    dma_constraint.ucr_high, 0, 0, &plist, atop(round_page(size)),
+	    UVM_PLA_WAITOK);
+	i = 0;
+	while ((pg = TAILQ_FIRST(&plist)) != NULL) {
+		pg->wire_count = 1;
+		atomic_setbits_int(&pg->pg_flags, PG_CLEAN | PG_FAKE);
+		KASSERT((pg->pg_flags & PG_DEV) == 0);
+		TAILQ_REMOVE(&plist, pg, pageq);
+		uvm_pagealloc_pg(pg, obj, off + ptoa(i++), NULL);
+	}
+}
+
+/*
  * uvm_pagealloc_strat: allocate vm_page from a particular free list.
  *
  * => return null if no pages free