update name of code to labcodes

labcodes/lab7/kern/mm/kmalloc.c

@@ -0,0 +1,305 @@
+#include <defs.h>
+#include <list.h>
+#include <memlayout.h>
+#include <assert.h>
+#include <kmalloc.h>
+#include <sync.h>
+#include <pmm.h>
+#include <stdio.h>
+
+/*
+ * SLOB Allocator: Simple List Of Blocks
+ *
+ * Matt Mackall <mpm@selenic.com> 12/30/03
+ *
+ * How SLOB works:
+ *
+ * The core of SLOB is a traditional K&R style heap allocator, with
+ * support for returning aligned objects. The granularity of this
+ * allocator is 8 bytes on x86, though it's perhaps possible to reduce
+ * this to 4 if it's deemed worth the effort. The slob heap is a
+ * singly-linked list of pages from __get_free_page, grown on demand
+ * and allocation from the heap is currently first-fit.
+ *
+ * Above this is an implementation of kmalloc/kfree. Blocks returned
+ * from kmalloc are 8-byte aligned and prepended with a 8-byte header.
+ * If kmalloc is asked for objects of PAGE_SIZE or larger, it calls
+ * __get_free_pages directly so that it can return page-aligned blocks
+ * and keeps a linked list of such pages and their orders. These
+ * objects are detected in kfree() by their page alignment.
+ *
+ * SLAB is emulated on top of SLOB by simply calling constructors and
+ * destructors for every SLAB allocation. Objects are returned with
+ * the 8-byte alignment unless the SLAB_MUST_HWCACHE_ALIGN flag is
+ * set, in which case the low-level allocator will fragment blocks to
+ * create the proper alignment. Again, objects of page-size or greater
+ * are allocated by calling __get_free_pages. As SLAB objects know
+ * their size, no separate size bookkeeping is necessary and there is
+ * essentially no allocation space overhead.
+ */
+
+
+//some helper
+#define spin_lock_irqsave(l, f) local_intr_save(f)
+#define spin_unlock_irqrestore(l, f) local_intr_restore(f)
+typedef unsigned int gfp_t;
+#ifndef PAGE_SIZE
+#define PAGE_SIZE PGSIZE
+#endif
+
+#ifndef L1_CACHE_BYTES
+#define L1_CACHE_BYTES 64
+#endif
+
+#ifndef ALIGN
+#define ALIGN(addr,size)   (((addr)+(size)-1)&(~((size)-1))) 
+#endif
+
+
+struct slob_block {
+	int units;
+	struct slob_block *next;
+};
+typedef struct slob_block slob_t;
+
+#define SLOB_UNIT sizeof(slob_t)
+#define SLOB_UNITS(size) (((size) + SLOB_UNIT - 1)/SLOB_UNIT)
+#define SLOB_ALIGN L1_CACHE_BYTES
+
+struct bigblock {
+	int order;
+	void *pages;
+	struct bigblock *next;
+};
+typedef struct bigblock bigblock_t;
+
+static slob_t arena = { .next = &arena, .units = 1 };
+static slob_t *slobfree = &arena;
+static bigblock_t *bigblocks;
+
+
+static void* __slob_get_free_pages(gfp_t gfp, int order)
+{
+  struct Page * page = alloc_pages(1 << order);
+  if(!page)
+    return NULL;
+  return page2kva(page);
+}
+
+#define __slob_get_free_page(gfp) __slob_get_free_pages(gfp, 0)
+
+static inline void __slob_free_pages(unsigned long kva, int order)
+{
+  free_pages(kva2page(kva), 1 << order);
+}
+
+static void slob_free(void *b, int size);
+
+static void *slob_alloc(size_t size, gfp_t gfp, int align)
+{
+  assert( (size + SLOB_UNIT) < PAGE_SIZE );
+
+	slob_t *prev, *cur, *aligned = 0;
+	int delta = 0, units = SLOB_UNITS(size);
+	unsigned long flags;
+
+	spin_lock_irqsave(&slob_lock, flags);
+	prev = slobfree;
+	for (cur = prev->next; ; prev = cur, cur = cur->next) {
+		if (align) {
+			aligned = (slob_t *)ALIGN((unsigned long)cur, align);
+			delta = aligned - cur;
+		}
+		if (cur->units >= units + delta) { /* room enough? */
+			if (delta) { /* need to fragment head to align? */
+				aligned->units = cur->units - delta;
+				aligned->next = cur->next;
+				cur->next = aligned;
+				cur->units = delta;
+				prev = cur;
+				cur = aligned;
+			}
+
+			if (cur->units == units) /* exact fit? */
+				prev->next = cur->next; /* unlink */
+			else { /* fragment */
+				prev->next = cur + units;
+				prev->next->units = cur->units - units;
+				prev->next->next = cur->next;
+				cur->units = units;
+			}
+
+			slobfree = prev;
+			spin_unlock_irqrestore(&slob_lock, flags);
+			return cur;
+		}
+		if (cur == slobfree) {
+			spin_unlock_irqrestore(&slob_lock, flags);
+
+			if (size == PAGE_SIZE) /* trying to shrink arena? */
+				return 0;
+
+			cur = (slob_t *)__slob_get_free_page(gfp);
+			if (!cur)
+				return 0;
+
+			slob_free(cur, PAGE_SIZE);
+			spin_lock_irqsave(&slob_lock, flags);
+			cur = slobfree;
+		}
+	}
+}
+
+static void slob_free(void *block, int size)
+{
+	slob_t *cur, *b = (slob_t *)block;
+	unsigned long flags;
+
+	if (!block)
+		return;
+
+	if (size)
+		b->units = SLOB_UNITS(size);
+
+	/* Find reinsertion point */
+	spin_lock_irqsave(&slob_lock, flags);
+	for (cur = slobfree; !(b > cur && b < cur->next); cur = cur->next)
+		if (cur >= cur->next && (b > cur || b < cur->next))
+			break;
+
+	if (b + b->units == cur->next) {
+		b->units += cur->next->units;
+		b->next = cur->next->next;
+	} else
+		b->next = cur->next;
+
+	if (cur + cur->units == b) {
+		cur->units += b->units;
+		cur->next = b->next;
+	} else
+		cur->next = b;
+
+	slobfree = cur;
+
+	spin_unlock_irqrestore(&slob_lock, flags);
+}
+
+
+
+void
+slob_init(void) {
+  cprintf("use SLOB allocator\n");
+}
+
+inline void 
+kmalloc_init(void) {
+    slob_init();
+    cprintf("kmalloc_init() succeeded!\n");
+}
+
+size_t
+slob_allocated(void) {
+  return 0;
+}
+
+size_t
+kallocated(void) {
+   return slob_allocated();
+}
+
+static int find_order(int size)
+{
+	int order = 0;
+	for ( ; size > 4096 ; size >>=1)
+		order++;
+	return order;
+}
+
+static void *__kmalloc(size_t size, gfp_t gfp)
+{
+	slob_t *m;
+	bigblock_t *bb;
+	unsigned long flags;
+
+	if (size < PAGE_SIZE - SLOB_UNIT) {
+		m = slob_alloc(size + SLOB_UNIT, gfp, 0);
+		return m ? (void *)(m + 1) : 0;
+	}
+
+	bb = slob_alloc(sizeof(bigblock_t), gfp, 0);
+	if (!bb)
+		return 0;
+
+	bb->order = find_order(size);
+	bb->pages = (void *)__slob_get_free_pages(gfp, bb->order);
+
+	if (bb->pages) {
+		spin_lock_irqsave(&block_lock, flags);
+		bb->next = bigblocks;
+		bigblocks = bb;
+		spin_unlock_irqrestore(&block_lock, flags);
+		return bb->pages;
+	}
+
+	slob_free(bb, sizeof(bigblock_t));
+	return 0;
+}
+
+void *
+kmalloc(size_t size)
+{
+  return __kmalloc(size, 0);
+}
+
+
+void kfree(void *block)
+{
+	bigblock_t *bb, **last = &bigblocks;
+	unsigned long flags;
+
+	if (!block)
+		return;
+
+	if (!((unsigned long)block & (PAGE_SIZE-1))) {
+		/* might be on the big block list */
+		spin_lock_irqsave(&block_lock, flags);
+		for (bb = bigblocks; bb; last = &bb->next, bb = bb->next) {
+			if (bb->pages == block) {
+				*last = bb->next;
+				spin_unlock_irqrestore(&block_lock, flags);
+				__slob_free_pages((unsigned long)block, bb->order);
+				slob_free(bb, sizeof(bigblock_t));
+				return;
+			}
+		}
+		spin_unlock_irqrestore(&block_lock, flags);
+	}
+
+	slob_free((slob_t *)block - 1, 0);
+	return;
+}
+
+
+unsigned int ksize(const void *block)
+{
+	bigblock_t *bb;
+	unsigned long flags;
+
+	if (!block)
+		return 0;
+
+	if (!((unsigned long)block & (PAGE_SIZE-1))) {
+		spin_lock_irqsave(&block_lock, flags);
+		for (bb = bigblocks; bb; bb = bb->next)
+			if (bb->pages == block) {
+				spin_unlock_irqrestore(&slob_lock, flags);
+				return PAGE_SIZE << bb->order;
+			}
+		spin_unlock_irqrestore(&block_lock, flags);
+	}
+
+	return ((slob_t *)block - 1)->units * SLOB_UNIT;
+}
+
+
+