nta.3

实现linux平台下零拷贝技术的软件包。

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 19c96d4..f550f95 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -327,6 +327,10 @@ #include <linux/slab.h>
 
 #include <asm/system.h>
 
+extern void *avl_alloc(unsigned int size, gfp_t gfp_mask);
+extern void avl_free(void *ptr, unsigned int size);
+extern int avl_init(void);
+
 extern void kfree_skb(struct sk_buff *skb);
 extern void	       __kfree_skb(struct sk_buff *skb);
 extern struct sk_buff *__alloc_skb(unsigned int size,
diff --git a/net/core/Makefile b/net/core/Makefile
index 2645ba4..d86d468 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -10,6 +10,8 @@ obj-$(CONFIG_SYSCTL) += sysctl_net_core.
 obj-y		     += dev.o ethtool.o dev_mcast.o dst.o netevent.o \
 			neighbour.o rtnetlink.o utils.o link_watch.o filter.o
 
+obj-y += alloc/
+
 obj-$(CONFIG_XFRM) += flow.o
 obj-$(CONFIG_SYSFS) += net-sysfs.o
 obj-$(CONFIG_NET_DIVERT) += dv.o
diff --git a/net/core/alloc/Makefile b/net/core/alloc/Makefile
new file mode 100644
index 0000000..779eba2
--- /dev/null
+++ b/net/core/alloc/Makefile
@@ -0,0 +1,3 @@
+obj-y		:= allocator.o
+
+allocator-y	:= avl.o zc.o
diff --git a/net/core/alloc/avl.c b/net/core/alloc/avl.c
new file mode 100644
index 0000000..bca6de9
--- /dev/null
+++ b/net/core/alloc/avl.c
@@ -0,0 +1,730 @@
+/*
+ * 	avl.c
+ * 
+ * 2006 Copyright (c) Evgeniy Polyakov <[e-mail]>
+ * All rights reserved.
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/skbuff.h>
+
+#include "avl.h"
+
+struct avl_allocator_data avl_allocator[NR_CPUS];
+
+#define avl_ptr_to_chunk(ptr, size)	(struct avl_chunk *)(ptr + size)
+
+/*
+ * Get node pointer from address.
+ */
+static inline struct avl_node *avl_get_node_ptr(unsigned long ptr)
+{
+	struct page *page = virt_to_page(ptr);
+	struct avl_node *node = (struct avl_node *)(page->lru.next);
+
+	return node;
+}
+
+/*
+ * Set node pointer for page for given address.
+ */
+static void avl_set_node_ptr(unsigned long ptr, struct avl_node *node, int order)
+{
+	int nr_pages = 1<<order, i;
+	struct page *page = virt_to_page(ptr);
+	
+	for (i=0; i<nr_pages; ++i) {
+		page->lru.next = (void *)node;
+		page++;
+	}
+}
+
+/*
+ * Get allocation CPU from address.
+ */
+static inline int avl_get_cpu_ptr(unsigned long ptr)
+{
+	struct page *page = virt_to_page(ptr);
+	int cpu = (int)(unsigned long)(page->lru.prev);
+
+	return cpu;
+}
+
+/*
+ * Set allocation cpu for page for given address.
+ */
+static void avl_set_cpu_ptr(unsigned long ptr, int cpu, int order)
+{
+	int nr_pages = 1<<order, i;
+	struct page *page = virt_to_page(ptr);
+			
+	for (i=0; i<nr_pages; ++i) {
+		page->lru.prev = (void *)(unsigned long)cpu;
+		page++;
+	}
+}
+
+/*
+ * Convert pointer to node's value.
+ * Node's value is a start address for contiguous chunk bound to given node.
+ */
+static inline unsigned long avl_ptr_to_value(void *ptr)
+{
+	struct avl_node *node = avl_get_node_ptr((unsigned long)ptr);
+	return node->value;
+}
+
+/*
+ * Convert pointer into offset from start address of the contiguous chunk
+ * allocated for appropriate node.
+ */
+static inline int avl_ptr_to_offset(void *ptr)
+{
+	return ((unsigned long)ptr - avl_ptr_to_value(ptr))/AVL_MIN_SIZE;
+}
+
+/*
+ * Count number of bits set down (until first unset is met in a mask) 
+ * to the smaller addresses including bit at @pos in @mask.
+ */
+unsigned int avl_count_set_down(unsigned long *mask, unsigned int pos)
+{
+	unsigned int stop, bits = 0;
+	int idx;
+	unsigned long p, m;
+
+	idx = pos/BITS_PER_LONG;
+	pos = pos%BITS_PER_LONG;
+
+	while (idx >= 0) {
+		m = (~0UL>>pos)<<pos;
+		p = mask[idx] | m;
+
+		if (!(mask[idx] & m))
+			break;
+
+		stop = fls(~p);
+
+		if (!stop) {
+			bits += pos + 1;
+			pos = BITS_PER_LONG - 1;
+			idx--;
+		} else {
+			bits += pos - stop + 1;
+			break;
+		}
+	}
+
+	return bits;
+}
+
+/*
+ * Count number of bits set up (until first unset is met in a mask) 
+ * to the bigger addresses including bit at @pos in @mask.
+ */
+unsigned int avl_count_set_up(unsigned long *mask, unsigned int mask_num, 
+		unsigned int pos)
+{
+	unsigned int idx, stop, bits = 0;
+	unsigned long p, m;
+
+	idx = pos/BITS_PER_LONG;
+	pos = pos%BITS_PER_LONG;
+
+	while (idx < mask_num) {
+		if (!pos)
+			m = 0;
+		else
+			m = (~0UL<<(BITS_PER_LONG-pos))>>(BITS_PER_LONG-pos);
+		p = mask[idx] | m;
+
+		if (!(mask[idx] & ~m))
+			break;
+
+		stop = ffs(~p);
+
+		if (!stop) {
+			bits += BITS_PER_LONG - pos;
+			pos = 0;
+			idx++;
+		} else {
+			bits += stop - pos - 1;
+			break;
+		}
+	}
+
+	return bits;
+}
+
+/*
+ * Fill @num bits from position @pos up with bit value @bit in a @mask.
+ */
+
+static void avl_fill_bits(unsigned long *mask, unsigned int mask_size, 
+		unsigned int pos, unsigned int num, unsigned int bit)
+{
+	unsigned int idx, start;
+
+	idx = pos/BITS_PER_LONG;
+	start = pos%BITS_PER_LONG;
+
+	while (num && idx < mask_size) {
+		unsigned long m = ((~0UL)>>start)<<start;
+
+		if (start + num <= BITS_PER_LONG) {
+			unsigned long upper_bits = BITS_PER_LONG - (start+num);
+
+			m = (m<<upper_bits)>>upper_bits;
+		}
+
+		if (bit)
+			mask[idx] |= m;
+		else
+			mask[idx] &= ~m;
+
+		if (start + num <= BITS_PER_LONG)
+			num = 0;
+		else {
+			num -= BITS_PER_LONG - start;
+			start = 0;
+			idx++;
+		}
+	}
+}
+
+/*
+ * Add free chunk into array.
+ */
+static inline void avl_container_insert(struct avl_container *c, unsigned int pos, int cpu)
+{
+	list_add_tail(&c->centry, &avl_allocator[cpu].avl_container_array[pos]);
+}
+
+/*
+ * Update zero-copy information in given @node.
+ * @node - node where given pointer @ptr lives
+ * @num - number of @AVL_MIN_SIZE chunks given pointer @ptr embeds
+ */
+static void avl_update_zc(struct avl_node *node, void *ptr, unsigned int size)
+{
+	struct zc_control *ctl = &zc_sniffer;
+
+	spin_lock(&ctl->zc_lock);
+	if (ctl->zc_used < ctl->zc_num) {
+		struct avl_chunk *ch = avl_ptr_to_chunk(ptr, size);
+		struct zc_data *zc = &ctl->zcb[ctl->zc_pos];
+		u32 off;
+
+		if (++ctl->zc_pos >= ctl->zc_num)
+			ctl->zc_pos = 0;
+
+		atomic_inc(&ch->refcnt);
+
+		off = ((unsigned long)node & ~PAGE_MASK)/sizeof(struct avl_node)*(1U<<node->entry->avl_node_order)*PAGE_SIZE;
+
+		zc->off = off+avl_ptr_to_offset(ptr)*AVL_MIN_SIZE;
+		zc->data.ptr = ptr;
+		zc->size = size;
+		zc->entry = node->entry->avl_entry_num;
+		zc->order = node->entry->avl_node_order;
+		zc->number = node->entry->avl_node_num;
+		ctl->zc_used++;
+		wake_up(&ctl->zc_wait);
+
+		ulog("%s: used: %u, pos: %u, num: %u, ptr: %p, size: %u.\n",
+				__func__, ctl->zc_used, ctl->zc_pos, ctl->zc_num, ptr, zc->size);
+	}
+	spin_unlock(&ctl->zc_lock);
+}
+
+/*
+ * Update node's bitmask of free/used chunks.
+ * If processed chunk size is bigger than requested one, 
+ * split it and add the rest into list of free chunks with appropriate size.
+ */
+static void avl_update_node(struct avl_container *c, unsigned int cpos, unsigned int size)
+{
+	struct avl_node *node = avl_get_node_ptr((unsigned long)c->ptr);
+	unsigned int num = AVL_ALIGN(size + sizeof(struct avl_chunk))/AVL_MIN_SIZE;
+
+	BUG_ON(cpos < num - 1);
+
+	avl_fill_bits(node->mask, ARRAY_SIZE(node->mask), avl_ptr_to_offset(c->ptr), num, 0);
+	
+	avl_update_zc(node, c, size);
+
+	if (cpos != num-1) {
+		void *ptr = c->ptr + AVL_ALIGN(size + sizeof(struct avl_chunk));
+
+		c = ptr;
+		c->ptr = ptr;
+
+		cpos -= num;
+
+		avl_container_insert(c, cpos, smp_processor_id());
+	}
+}
+
+/*
+ * Dereference free chunk into container and add it into list of free
+ * chunks with appropriate size.
+ */
+static int avl_container_add(void *ptr, unsigned int size, int cpu)
+{
+	struct avl_container *c = ptr;
+	unsigned int pos = AVL_ALIGN(size)/AVL_MIN_SIZE-1;
+
+	if (!size)
+		return -EINVAL;
+
+	c->ptr = ptr;
+	avl_container_insert(c, pos, cpu);
+
+	return 0;
+}
+
+/*
+ * Dequeue first free chunk from the list.
+ */
+static inline struct avl_container *avl_dequeue(struct list_head *head)
+{
+	struct avl_container *cnt;
+
+	cnt = list_entry(head->next, struct avl_container, centry);
+	list_del(&cnt->centry);
+
+	return cnt;
+}
+
+/*
+ * Add new node entry int network allocator.
+ * must be called with disabled preemtpion.
+ */
+static void avl_node_entry_commit(struct avl_node_entry *entry, int cpu)
+{
+	int i, idx, off;
+
+	idx = off = 0;
+	for (i=0; i<entry->avl_node_num; ++i) {
+		struct avl_node *node;
+
+		node = &entry->avl_node_array[idx][off];
+
+		if (++off >= AVL_NODES_ON_PAGE) {
+			idx++;
+			off = 0;
+		}
+
+		node->entry = entry;
+
+		avl_set_cpu_ptr(node->value, cpu, entry->avl_node_order);
+		avl_set_node_ptr(node->value, node, entry->avl_node_order);
+		avl_container_add((void *)node->value, (1<<entry->avl_node_order)<<PAGE_SHIFT, cpu);
+	}
+
+	spin_lock(&avl_allocator[cpu].avl_node_lock);
+	entry->avl_entry_num = avl_allocator[cpu].avl_entry_num;
+	list_add_tail(&entry->node_entry, &avl_allocator[cpu].avl_node_list);
+	avl_allocator[cpu].avl_entry_num++;
+	spin_unlock(&avl_allocator[cpu].avl_node_lock);
+}
+
+/*
+ * Simple cache growing function - allocate as much as possible,
+ * but no more than @AVL_NODE_NUM pages when there is a need for that.
+ */
+static struct avl_node_entry *avl_node_entry_alloc(gfp_t gfp_mask, int order)
+{
+	struct avl_node_entry *entry;
+	int i, num = 0, idx, off, j;
+	unsigned long ptr;
+
+	entry = kzalloc(sizeof(struct avl_node_entry), gfp_mask);
+	if (!entry)
+		return NULL;
+
+	entry->avl_node_array = kzalloc(AVL_NODE_PAGES * sizeof(void *), gfp_mask);
+	if (!entry->avl_node_array)
+		goto err_out_free_entry;
+
+	for (i=0; i<AVL_NODE_PAGES; ++i) {
+		entry->avl_node_array[i] = (struct avl_node *)__get_free_page(gfp_mask);
+		if (!entry->avl_node_array[i]) {
+			num = i;
+			goto err_out_free;
+		}
+	}
+
+	idx = off = 0;
+