Re: [RFC v2 16/83] Initialize block map and free lists in nova_init().

From: Andiry Xu
Date: Sun Mar 11 2018 - 17:30:38 EST

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On Sun, Mar 11, 2018 at 5:12 AM, Nikolay Borisov
<n.borisov.lkml@xxxxxxxxx> wrote:
>
>
> On 10.03.2018 20:17, Andiry Xu wrote:
>> From: Andiry Xu <jix024@xxxxxxxxxxx>
>>
>> NOVA divides the pmem range equally among per-CPU free lists,
>> and format the red-black trees by inserting the initial free range.
>>
>> Signed-off-by: Andiry Xu <jix024@xxxxxxxxxxx>
>> ---
>> fs/nova/balloc.c | 161 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> fs/nova/balloc.h | 13 ++++-
>> fs/nova/super.c | 2 +
>> 3 files changed, 175 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/nova/balloc.c b/fs/nova/balloc.c
>> index 450c942..cb627db 100644
>> --- a/fs/nova/balloc.c
>> +++ b/fs/nova/balloc.c
>> @@ -55,4 +55,165 @@ void nova_delete_free_lists(struct super_block *sb)
>> sbi->free_lists = NULL;
>> }
>>
>> +// Initialize a free list. Each CPU gets an equal share of the block space to
>> +// manage.
>> +static void nova_init_free_list(struct super_block *sb,
>> + struct free_list *free_list, int index)
>> +{
>> + struct nova_sb_info *sbi = NOVA_SB(sb);
>> + unsigned long per_list_blocks;
>> +
>> + per_list_blocks = sbi->num_blocks / sbi->cpus;
>
> nit: You've already initialised per_list_blocks in nova_init_blockmap,
> which calls this function. So just reference it, rather than performing
> the the divison every time
>

Thanks for catching this.

>> +
>> + free_list->block_start = per_list_blocks * index;
>> + free_list->block_end = free_list->block_start +
>> + per_list_blocks - 1;
>> + if (index == 0)
>> + free_list->block_start += sbi->head_reserved_blocks;
>> + if (index == sbi->cpus - 1)
>> + free_list->block_end -= sbi->tail_reserved_blocks;
>> +}
>> +
>> +inline struct nova_range_node *nova_alloc_blocknode(struct super_block *sb)
>> +{
>> + return nova_alloc_range_node(sb);
>> +}
>> +
>> +inline void nova_free_blocknode(struct super_block *sb,
>> + struct nova_range_node *node)
>> +{
>> + nova_free_range_node(node);
>> +}
>> +
>> +void nova_init_blockmap(struct super_block *sb, int recovery)
>> +{
>> + struct nova_sb_info *sbi = NOVA_SB(sb);
>> + struct rb_root *tree;
>> + struct nova_range_node *blknode;
>> + struct free_list *free_list;
>> + int i;
>> + int ret;
>> +
>> + /* Divide the block range among per-CPU free lists */
>> + sbi->per_list_blocks = sbi->num_blocks / sbi->cpus;
>> + for (i = 0; i < sbi->cpus; i++) {
>> + free_list = nova_get_free_list(sb, i);
>> + tree = &(free_list->block_free_tree);
>> + nova_init_free_list(sb, free_list, i);
>> +
>> + /* For recovery, update these fields later */
>> + if (recovery == 0) {
>> + free_list->num_free_blocks = free_list->block_end -
>> + free_list->block_start + 1;
>> +
>> + blknode = nova_alloc_blocknode(sb);
>> + if (blknode == NULL)
>> + return;
>> + blknode->range_low = free_list->block_start;
>> + blknode->range_high = free_list->block_end;
>> + ret = nova_insert_blocktree(sbi, tree, blknode);
>> + if (ret) {
>> + nova_err(sb, "%s failed\n", __func__);
>> + nova_free_blocknode(sb, blknode);
>> + return;
>> + }
>> + free_list->first_node = blknode;
>> + free_list->last_node = blknode;
>> + free_list->num_blocknode = 1;
>> + }
>> +
>> + nova_dbgv("%s: free list %d: block start %lu, end %lu, %lu free blocks\n",
>> + __func__, i,
>> + free_list->block_start,
>> + free_list->block_end,
>> + free_list->num_free_blocks);
>> + }
>> +}
>> +
>> +static inline int nova_rbtree_compare_rangenode(struct nova_range_node *curr,
>> + unsigned long range_low)
>> +{
>> + if (range_low < curr->range_low)
>> + return -1;
>> + if (range_low > curr->range_high)
>> + return 1;
>>
>> + return 0;
>> +}
>> +
>> +int nova_find_range_node(struct nova_sb_info *sbi,
>> + struct rb_root *tree, unsigned long range_low,
>> + struct nova_range_node **ret_node)
>
> Instead of having a **ret_node pointer as an argument, just make the
> function return struct nova_range *node and have callers check for null:
>
> struct nova_range_node *node = nova_find_range_node(sbi, tree, range);
>
> if (ret) {
> //do stuff with *node
> }
>

I pass **ret_node as an argument because if the target node is not
found, nova_find_range_node() returns the father node in
nova_find_free_slot(). So there is possibility that it returns 0 and a
not-NULL ret_node. Having it as a parameter makes this clearer.

Thanks,
Andiry

>> +{
>> + struct nova_range_node *curr = NULL;
>> + struct rb_node *temp;
>> + int compVal;
>> + int ret = 0;
>> +
>> + temp = tree->rb_node;
>> +
>> + while (temp) {
>> + curr = container_of(temp, struct nova_range_node, node);
>> + compVal = nova_rbtree_compare_rangenode(curr, range_low);
>> +
>> + if (compVal == -1) {
>> + temp = temp->rb_left;
>> + } else if (compVal == 1) {
>> + temp = temp->rb_right;
>> + } else {
>> + ret = 1;
>> + break;
>> + }
>> + }
>> +
>> + *ret_node = curr;
>> + return ret;
>> +}
>> +
>> +
>> +int nova_insert_range_node(struct rb_root *tree,
>> + struct nova_range_node *new_node)
>> +{
>> + struct nova_range_node *curr;
>> + struct rb_node **temp, *parent;
>> + int compVal;
>> +
>> + temp = &(tree->rb_node);
>> + parent = NULL;
>> +
>> + while (*temp) {
>> + curr = container_of(*temp, struct nova_range_node, node);
>> + compVal = nova_rbtree_compare_rangenode(curr,
>> + new_node->range_low);
>> + parent = *temp;
>> +
>> + if (compVal == -1) {
>> + temp = &((*temp)->rb_left);
>> + } else if (compVal == 1) {
>> + temp = &((*temp)->rb_right);
>> + } else {
>> + nova_dbg("%s: entry %lu - %lu already exists: %lu - %lu\n",
>> + __func__, new_node->range_low,
>> + new_node->range_high, curr->range_low,
>> + curr->range_high);
>> + return -EINVAL;
>> + }
>> + }
>> +
>> + rb_link_node(&new_node->node, parent, temp);
>> + rb_insert_color(&new_node->node, tree);
>> +
>> + return 0;
>> +}
>> +
>> +inline int nova_insert_blocktree(struct nova_sb_info *sbi,
>> + struct rb_root *tree, struct nova_range_node *new_node)
>> +{
>> + int ret;
>> +
>> + ret = nova_insert_range_node(tree, new_node);
>> + if (ret)
>> + nova_dbg("ERROR: %s failed %d\n", __func__, ret);
>> +
>> + return ret;
>> +}
>> diff --git a/fs/nova/balloc.h b/fs/nova/balloc.h
>> index e7c7a1d..57a93e4 100644
>> --- a/fs/nova/balloc.h
>> +++ b/fs/nova/balloc.h
>> @@ -62,5 +62,16 @@ enum alloc_type {
>>
>> int nova_alloc_block_free_lists(struct super_block *sb);
>> void nova_delete_free_lists(struct super_block *sb);
>> -
>> +inline struct nova_range_node *nova_alloc_blocknode(struct super_block *sb);
>> +inline void nova_free_blocknode(struct super_block *sb,
>> + struct nova_range_node *bnode);
>> +extern void nova_init_blockmap(struct super_block *sb, int recovery);
>> +inline int nova_insert_blocktree(struct nova_sb_info *sbi,
>> + struct rb_root *tree, struct nova_range_node *new_node);
>> +
>> +extern int nova_insert_range_node(struct rb_root *tree,
>> + struct nova_range_node *new_node);
>> +extern int nova_find_range_node(struct nova_sb_info *sbi,
>> + struct rb_root *tree, unsigned long range_low,
>> + struct nova_range_node **ret_node);
>> #endif
>> diff --git a/fs/nova/super.c b/fs/nova/super.c
>> index 43b24a7..9762f26 100644
>> --- a/fs/nova/super.c
>> +++ b/fs/nova/super.c
>> @@ -376,6 +376,8 @@ static struct nova_inode *nova_init(struct super_block *sb,
>> pi->nova_ino = NOVA_BLOCKNODE_INO;
>> nova_flush_buffer(pi, CACHELINE_SIZE, 1);
>>
>> + nova_init_blockmap(sb, 0);
>> +
>> sbi->nova_sb->s_size = cpu_to_le64(size);
>> sbi->nova_sb->s_blocksize = cpu_to_le32(blocksize);
>> sbi->nova_sb->s_magic = cpu_to_le32(NOVA_SUPER_MAGIC);
>>

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In reply to: Nikolay Borisov: "Re: [RFC v2 16/83] Initialize block map and free lists in nova_init()."
Next in thread: Andiry Xu: "[RFC v2 14/83] Add range node kmem cache."
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