From: Ben Gras <ben@minix3.org>
Date: Mon, 28 Jun 2010 18:12:32 +0000 (+0000)
Subject: memory driver: use mmap to pre-allocate ramdisks to avoid overcommit.
X-Git-Tag: v3.1.8~319
X-Git-Url: http://zhaoyanbai.com/repos/migration-4to9?a=commitdiff_plain;h=635a8f772cfe973c942eecc45a5fca9fab4bf1df;p=minix.git

memory driver: use mmap to pre-allocate ramdisks to avoid overcommit.
---

diff --git a/drivers/memory/memory.c b/drivers/memory/memory.c
index 3e7a9469c..0d2f1ed90 100644
--- a/drivers/memory/memory.c
+++ b/drivers/memory/memory.c
@@ -445,7 +445,7 @@ message *m_ptr;				/* pointer to control message */
 			panic("huge old ramdisk");
 		}
 		size = ex64lo(dv->dv_size);
-		free((void *) m_vaddrs[dev]);
+		munmap((void *) m_vaddrs[dev], size);
 		m_vaddrs[dev] = (vir_bytes) NULL;
 	}
 
@@ -454,11 +454,11 @@ message *m_ptr;				/* pointer to control message */
 #endif
 
 	/* Try to allocate a piece of memory for the RAM disk. */
-	if(!(mem = malloc(ramdev_size))) {
+	if((mem = mmap(NULL, ramdev_size, PROT_READ|PROT_WRITE,
+	  MAP_PREALLOC|MAP_ANON, -1, 0)) == MAP_FAILED) {
 	    printf("MEM: failed to get memory for ramdisk\n");
             return(ENOMEM);
-        } 
-	memset(mem, 0, ramdev_size);
+        }
 
 	m_vaddrs[dev] = (vir_bytes) mem;