From: Cristiano Giuffrida <cristiano@minix3.org>
Date: Tue, 20 Jul 2010 18:57:25 +0000 (+0000)
Subject: COW for physically contiguous blocks in VM
X-Git-Tag: v3.1.8~178
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/mult.png?a=commitdiff_plain;h=40b4e71db2525a51b1ed3bd7c9925fe8608872d3;p=minix.git

COW for physically contiguous blocks in VM
---

diff --git a/servers/vm/mmap.c b/servers/vm/mmap.c
index 9257f732f..47d715b57 100644
--- a/servers/vm/mmap.c
+++ b/servers/vm/mmap.c
@@ -61,6 +61,11 @@ PUBLIC int do_mmap(message *m)
 			return EINVAL;
 		}
 
+		/* Contiguous phys memory has to be preallocated. */
+		if((m->VMM_FLAGS & (MAP_CONTIG|MAP_PREALLOC)) == MAP_CONTIG) {
+			return EINVAL;
+		}
+
 		if(m->VMM_FLAGS & MAP_PREALLOC) mfflags |= MF_PREALLOC;
 		if(m->VMM_FLAGS & MAP_LOWER16M) vrflags |= VR_LOWER16MB;
 		if(m->VMM_FLAGS & MAP_LOWER1M)  vrflags |= VR_LOWER1MB;
diff --git a/servers/vm/region.c b/servers/vm/region.c
index 2b6c67d9d..752f1382d 100644
--- a/servers/vm/region.c
+++ b/servers/vm/region.c
@@ -969,6 +969,7 @@ physr_iter *iter;
 	u32_t allocflags;
 	phys_bytes physaddr;
 	struct phys_region *newpr;
+	int region_has_single_block;
 	int written = 0; 
 #if SANITYCHECKS
 	written = ph->written;
@@ -1014,7 +1015,8 @@ physr_iter *iter;
 
 	/* Put new free memory in. */
 	allocflags = vrallocflags(region->flags);
-	assert(!(allocflags & PAF_CONTIG));
+	region_has_single_block = (offset == 0 && length == region->length);
+	assert(region_has_single_block || !(allocflags & PAF_CONTIG));
 	assert(!(allocflags & PAF_CLEAR));
 
 	if(map_new_physblock(vmp, region, offset, length,