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
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
Hi Jaegeuk,
> -----Original Message-----
> From: Jaegeuk Kim [mailto:[email protected]]
> Sent: Monday, December 15, 2014 4:27 PM
> To: Chao Yu
> Cc: Changman Lee; [email protected]; [email protected];
> [email protected]
> Subject: Re: [f2fs-dev][PATCH] f2fs: merge two uchar variable in struct nat_entry to reduce
> memory cost
>
> Hi Chao,
>
> I found a bug in this patch.
Oh, it's my bad. I will fix this as you suggested.
Thank you for helping to find this bug. :)
Regards,
Yu
>
> 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,
>