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.
changes from v1:
o introduce inline copy_node_info() to copy valid data from node info suggested
by Jaegeuk Kim, it can avoid bug.
Signed-off-by: Chao Yu <[email protected]>
---
fs/f2fs/node.c | 4 ++--
fs/f2fs/node.h | 33 ++++++++++++++++++++++-----------
2 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index f83326c..5aa54a0 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -268,7 +268,7 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
e = __lookup_nat_cache(nm_i, ni->nid);
if (!e) {
e = grab_nat_entry(nm_i, ni->nid);
- e->ni = *ni;
+ copy_node_info(&e->ni, ni);
f2fs_bug_on(sbi, ni->blk_addr == NEW_ADDR);
} else if (new_blkaddr == NEW_ADDR) {
/*
@@ -276,7 +276,7 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
* previous nat entry can be remained in nat cache.
* So, reinitialize it with new information.
*/
- e->ni = *ni;
+ copy_node_info(&e->ni, ni);
f2fs_bug_on(sbi, ni->blk_addr != NULL_ADDR);
}
diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
index d10b644..eb59167 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 */
};
@@ -63,20 +64,30 @@ struct nat_entry {
#define inc_node_version(version) (++version)
+static inline void copy_node_info(struct node_info *dst,
+ struct node_info *src)
+{
+ dst->nid = src->nid;
+ dst->ino = src->ino;
+ dst->blk_addr = src->blk_addr;
+ dst->version = src->version;
+ /* should not copy flag here */
+}
+
static inline void set_nat_flag(struct nat_entry *ne,
unsigned int type, bool set)
{
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 Yu,
This patch is effective only in 32 bit machine. In case of 64 bit
machine, nat_entry will be aligned in 8 bytes due to pointer variable
(i.e. struct list_head). So it can't get any benefit to reduce memory
usage. In the case of node_info, however, it will be gain in terms of
memory usage.
Hence, I think it's not correct for commit log to describe this patch.
Thanks,
Reviewed-by: Changman Lee <[email protected]>
2014-12-15 18:33 GMT+09:00 Chao Yu <[email protected]>:
> 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.
>
> changes from v1:
> o introduce inline copy_node_info() to copy valid data from node info suggested
> by Jaegeuk Kim, it can avoid bug.
>
> Signed-off-by: Chao Yu <[email protected]>
> ---
> fs/f2fs/node.c | 4 ++--
> fs/f2fs/node.h | 33 ++++++++++++++++++++++-----------
> 2 files changed, 24 insertions(+), 13 deletions(-)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index f83326c..5aa54a0 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -268,7 +268,7 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
> e = __lookup_nat_cache(nm_i, ni->nid);
> if (!e) {
> e = grab_nat_entry(nm_i, ni->nid);
> - e->ni = *ni;
> + copy_node_info(&e->ni, ni);
> f2fs_bug_on(sbi, ni->blk_addr == NEW_ADDR);
> } else if (new_blkaddr == NEW_ADDR) {
> /*
> @@ -276,7 +276,7 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
> * previous nat entry can be remained in nat cache.
> * So, reinitialize it with new information.
> */
> - e->ni = *ni;
> + copy_node_info(&e->ni, ni);
> f2fs_bug_on(sbi, ni->blk_addr != NULL_ADDR);
> }
>
> diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
> index d10b644..eb59167 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 */
> };
>
> @@ -63,20 +64,30 @@ struct nat_entry {
>
> #define inc_node_version(version) (++version)
>
> +static inline void copy_node_info(struct node_info *dst,
> + struct node_info *src)
> +{
> + dst->nid = src->nid;
> + dst->ino = src->ino;
> + dst->blk_addr = src->blk_addr;
> + dst->version = src->version;
> + /* should not copy flag here */
> +}
> +
> static inline void set_nat_flag(struct nat_entry *ne,
> unsigned int type, bool set)
> {
> 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
>
>
>
> ------------------------------------------------------------------------------
> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
> from Actuate! Instantly Supercharge Your Business Reports and Dashboards
> with Interactivity, Sharing, Native Excel Exports, App Integration & more
> Get technology previously reserved for billion-dollar corporations, FREE
> http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk
> _______________________________________________
> Linux-f2fs-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
Hi Changman,
> -----Original Message-----
> From: Changman Lee [mailto:[email protected]]
> Sent: Wednesday, December 17, 2014 11:09 PM
> To: Chao Yu
> Cc: Jaegeuk Kim; Changman Lee; [email protected]; [email protected];
> [email protected]
> Subject: Re: [f2fs-dev] [PATCH v2] f2fs: merge two uchar variable in struct node_info to reduce
> memory cost
>
> Hi Yu,
>
> This patch is effective only in 32 bit machine. In case of 64 bit
> machine, nat_entry will be aligned in 8 bytes due to pointer variable
> (i.e. struct list_head). So it can't get any benefit to reduce memory
> usage. In the case of node_info, however, it will be gain in terms of
> memory usage.
> Hence, I think it's not correct for commit log to describe this patch.
>
Thanks for your review! :)
AFFIK, in 64 bit machine, size of struct nat_entry is 40 bytes before this patch
apply, the reason is that our compiler will fill 3 bytes pads after flag as
nid's offset should align to type size of nid, and then fill 7 byte pads after
version as size of structure should align to 64 bits when the struct size is bigger
than 64 bits.
layout of struct nat_entry:
|-----8 bytes-----|
|list.next |
|list.prev |
|flag |nid |
|ino |blk_addr|
|version |
After we apply this patch, size of struct nat_entry will be reduced to 32 bytes.
Please correct me if I'm wrong.
Anyway, I agreed that commit log should be uptodate.
Thanks,
Yu
> Thanks,
>
> Reviewed-by: Changman Lee <[email protected]>
>
On Thu, Dec 18, 2014 at 02:29:51PM +0800, Chao Yu wrote:
> Hi Changman,
>
> > -----Original Message-----
> > From: Changman Lee [mailto:[email protected]]
> > Sent: Wednesday, December 17, 2014 11:09 PM
> > To: Chao Yu
> > Cc: Jaegeuk Kim; Changman Lee; [email protected]; [email protected];
> > [email protected]
> > Subject: Re: [f2fs-dev] [PATCH v2] f2fs: merge two uchar variable in struct node_info to reduce
> > memory cost
> >
> > Hi Yu,
> >
> > This patch is effective only in 32 bit machine. In case of 64 bit
> > machine, nat_entry will be aligned in 8 bytes due to pointer variable
> > (i.e. struct list_head). So it can't get any benefit to reduce memory
> > usage. In the case of node_info, however, it will be gain in terms of
> > memory usage.
> > Hence, I think it's not correct for commit log to describe this patch.
> >
>
> Thanks for your review! :)
>
> AFFIK, in 64 bit machine, size of struct nat_entry is 40 bytes before this patch
> apply, the reason is that our compiler will fill 3 bytes pads after flag as
> nid's offset should align to type size of nid, and then fill 7 byte pads after
> version as size of structure should align to 64 bits when the struct size is bigger
> than 64 bits.
> layout of struct nat_entry:
> |-----8 bytes-----|
> |list.next |
> |list.prev |
> |flag |nid |
> |ino |blk_addr|
> |version |
> After we apply this patch, size of struct nat_entry will be reduced to 32 bytes.
> Please correct me if I'm wrong.
Hi,
Sorry, you're right.
I miscalculated.
Thanks,
>
> Anyway, I agreed that commit log should be uptodate.
>
> Thanks,
> Yu
>
> > Thanks,
> >
> > Reviewed-by: Changman Lee <[email protected]>
> >