mem stuff

kern/arch/mips/vm/dumbvm.c

@@ -55,6 +55,10 @@
  * it's cutting (there are many) and why, and more importantly, how.
  */
 
+/* under dumbvm, always have 72k of user stack */
+/* (this must be > 64K so argument blocks of size ARG_MAX will fit) */
+#define DUMBVM_STACKPAGES    18
+
 
 /*
  * Bitmap utils
@@ -63,11 +67,6 @@
 #define resetBit(A,k)   ( A[(k/32)] &= ~(1 << (k%32)) )
 #define checkBit(A,k)    ( A[(k/32)] & (1 << (k%32)) )
 
-
-/* under dumbvm, always have 72k of user stack */
-/* (this must be > 64K so argument blocks of size ARG_MAX will fit) */
-#define DUMBVM_STACKPAGES    18
-
 /*
  * Wrap ram_stealmem in a spinlock.
  */
@@ -77,26 +76,35 @@ static struct spinlock freemem_lock = SPINLOCK_INITIALIZER;
 static uint32_t *freeRamFrames = NULL;
 static unsigned long *allocSize = NULL;
 static int nRamFrames = 0;
+
 static int allocTableActive = 0;
 
+static int isTableActive () {
+  int active;
+  spinlock_acquire(&freemem_lock);
+  active = allocTableActive;
+  spinlock_release(&freemem_lock);
+  return active;
+}
+
 void
 vm_bootstrap(void)
 {
-	int i;
-  nRamFrames = ((int)ram_getsize())/PAGE_SIZE;
-  /* alloc freeRamFrame and allocSize */
+  int i;
+  nRamFrames = ((int)ram_getsize())/PAGE_SIZE;  
+  /* alloc freeRamFrame and allocSize */  
   freeRamFrames = kmalloc(sizeof(uint32_t)*(nRamFrames/32 + 1));
-  if (freeRamFrames==NULL) return;
+  if (freeRamFrames==NULL) return;  
   allocSize     = kmalloc(sizeof(unsigned long)*nRamFrames);
-  if (allocSize==NULL) {
+  if (allocSize==NULL) {    
     /* reset to disable this vm management */
     freeRamFrames = NULL; return;
   }
-  for (i=0; i<nRamFrames; i++) {
+  for (i=0; i<nRamFrames; i++) {    
 		if (i<(nRamFrames/32 + 1)) {
 	    freeRamFrames[i] = (uint32_t)0;
 		}
-    allocSize[i]     = 0;
+    allocSize[i]     = 0;  
   }
   spinlock_acquire(&freemem_lock);
   allocTableActive = 1;
@@ -110,8 +118,7 @@ vm_bootstrap(void)
  * avoid the situation where syscall-layer code that works ok with
  * dumbvm starts blowing up during the VM assignment.
  */
-static
-void
+static void
 dumbvm_can_sleep(void)
 {
 	if (CURCPU_EXISTS()) {
@@ -123,16 +130,13 @@ dumbvm_can_sleep(void)
 	}
 }
 
-static paddr_t
+static paddr_t 
 getfreeppages(unsigned long npages) {
-  paddr_t addr;
+  paddr_t addr; 
   long i, first, found, np = (long)npages;
 
+  if (!isTableActive()) return 0; 
   spinlock_acquire(&freemem_lock);
-	if (!allocTableActive) {
-		spinlock_release(&freemem_lock);
-		return 0;
-	}
   for (i=0,first=found=-1; i<nRamFrames; i++) {
     if (checkBit(freeRamFrames, i)) {
       if (i==0 || !checkBit(freeRamFrames, i-1))
@@ -143,7 +147,7 @@ getfreeppages(unsigned long npages) {
       }
     }
   }
-
+ 
   if (found>=0) {
     for (i=found; i<found+np; i++) {
 			resetBit(freeRamFrames, i);
@@ -160,28 +164,6 @@ getfreeppages(unsigned long npages) {
   return addr;
 }
 
-static int 
-freeppages(paddr_t addr, unsigned long npages){
-  long i, first, np=(long)npages;	
-
-	spinlock_acquire(&freemem_lock);
-	if (!allocTableActive) {
-		spinlock_release(&freemem_lock);
-		return 0;
-	}
-
-  first = addr/PAGE_SIZE;
-  KASSERT(allocSize!=NULL);
-  KASSERT(nRamFrames>first);
-
-  for (i=first; i<first+np; i++) {
-		setBit(freeRamFrames, i);
-  }
-  spinlock_release(&freemem_lock);
-
-  return 1;
-}
-
 static paddr_t
 getppages(unsigned long npages)
 {
@@ -195,17 +177,31 @@ getppages(unsigned long npages)
     addr = ram_stealmem(npages);
     spinlock_release(&stealmem_lock);
   }
-	if (addr!=0) {
+  if (addr!=0 && isTableActive()) {
     spinlock_acquire(&freemem_lock);
-		if (!allocTableActive) {
-			spinlock_release(&freemem_lock);
-			return addr;
-		}
-		allocSize[addr/PAGE_SIZE] = npages;
+    allocSize[addr/PAGE_SIZE] = npages;
     spinlock_release(&freemem_lock);
-	}
+  } 
 
-	return addr;
+  return addr;
+}
+
+static int 
+freeppages(paddr_t addr, unsigned long npages){
+  long i, first, np=(long)npages;	
+
+  if (!isTableActive()) return 0; 
+  first = addr/PAGE_SIZE;
+  KASSERT(allocSize!=NULL);
+  KASSERT(nRamFrames>first);
+
+  spinlock_acquire(&freemem_lock);
+  for (i=first; i<first+np; i++) {
+		setBit(freeRamFrames, i);
+  }
+  spinlock_release(&freemem_lock);
+
+  return 1;
 }
 
 /* Allocate/free some kernel-space virtual pages */
@@ -222,20 +218,15 @@ alloc_kpages(unsigned npages)
 	return PADDR_TO_KVADDR(pa);
 }
 
-void
-free_kpages(vaddr_t addr)
-{
-	spinlock_acquire(&freemem_lock);
-	if (!allocTableActive) {
-		spinlock_release(&freemem_lock);
-		return;
-	}
-	spinlock_release(&freemem_lock);
-	paddr_t paddr = addr - MIPS_KSEG0;
-	long first = paddr/PAGE_SIZE;	
-	KASSERT(allocSize!=NULL);
-	KASSERT(nRamFrames>first);
-	freeppages(paddr, allocSize[first]);	
+void 
+free_kpages(vaddr_t addr){
+  if (isTableActive()) {
+    paddr_t paddr = addr - MIPS_KSEG0;
+    long first = paddr/PAGE_SIZE;	
+    KASSERT(allocSize!=NULL);
+    KASSERT(nRamFrames>first);
+    freeppages(paddr, allocSize[first]);	
+  }
 }
 
 void