Hi Chao,
I found a bug in this patch.
In set_node_addr,
down_write(&nm_i->nat_tree_lock);
e = __lookup_nat_cache(nm_i, ni->nid);
if (!e) {
e = grab_nat_entry(nm_i, ni->nid);
e->ni = *ni;
^^^^^^^^^^^^
this line should not copy ni.flag.
f2fs_bug_on(sbi, ni->blk_addr == NEW_ADDR);
} else if (new_blkaddr == NEW_ADDR) {
/*
* when nid is reallocated,
* previous nat entry can be remained in nat cache.
* So, reinitialize it with new information.
*/
e->ni = *ni;
^^^^^^^^^^^^
ditto.
f2fs_bug_on(sbi, ni->blk_addr != NULL_ADDR);
}
So, please add inline function in node.h like:
static inline void copy_node_info(dst, src)
{
dst->nid = src->nid;
dst->ino = src->ino;
dst->blk_addr = src->blk_addr;
dst->version = src->version;
/* should not copy flag here */
}
Then let's use this function.
Thanks,
On Mon, Dec 08, 2014 at 03:13:49PM +0800, Chao Yu wrote:
> This patch moves one member of struct nat_entry: _flag_ to struct node_info,
> so _version_ in struct node_info and _flag_ with unsigned char type will merge
> to one 32-bit space in register/memory. Then the size of nat_entry will reduce
> its size from 28 bytes to 24 bytes and slab memory using by f2fs will be
> reduced.
>
> Signed-off-by: Chao Yu <[email protected]>
> ---
> fs/f2fs/node.h | 23 ++++++++++++-----------
> 1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
> index d10b644..27a7318 100644
> --- a/fs/f2fs/node.h
> +++ b/fs/f2fs/node.h
> @@ -29,6 +29,14 @@
> /* return value for read_node_page */
> #define LOCKED_PAGE 1
>
> +/* For flag in struct node_info */
> +enum {
> + IS_CHECKPOINTED, /* is it checkpointed before? */
> + HAS_FSYNCED_INODE, /* is the inode fsynced before? */
> + HAS_LAST_FSYNC, /* has the latest node fsync mark? */
> + IS_DIRTY, /* this nat entry is dirty? */
> +};
> +
> /*
> * For node information
> */
> @@ -37,18 +45,11 @@ struct node_info {
> nid_t ino; /* inode number of the node's owner */
> block_t blk_addr; /* block address of the node */
> unsigned char version; /* version of the node */
> -};
> -
> -enum {
> - IS_CHECKPOINTED, /* is it checkpointed before? */
> - HAS_FSYNCED_INODE, /* is the inode fsynced before? */
> - HAS_LAST_FSYNC, /* has the latest node fsync mark? */
> - IS_DIRTY, /* this nat entry is dirty? */
> + unsigned char flag; /* for node information bits */
> };
>
> struct nat_entry {
> struct list_head list; /* for clean or dirty nat list */
> - unsigned char flag; /* for node information bits */
> struct node_info ni; /* in-memory node information */
> };
>
> @@ -68,15 +69,15 @@ static inline void set_nat_flag(struct nat_entry *ne,
> {
> unsigned char mask = 0x01 << type;
> if (set)
> - ne->flag |= mask;
> + ne->ni.flag |= mask;
> else
> - ne->flag &= ~mask;
> + ne->ni.flag &= ~mask;
> }
>
> static inline bool get_nat_flag(struct nat_entry *ne, unsigned int type)
> {
> unsigned char mask = 0x01 << type;
> - return ne->flag & mask;
> + return ne->ni.flag & mask;
> }
>
> static inline void nat_reset_flag(struct nat_entry *ne)
> --
> 2.1.2
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