Re: [PATCH 3/4] f2fs: optimize scan_nat_page()

[Jaegeuk Kim]

Hi,

2013-05-06 (월), 23:15 +0800, Haicheng Li:
> When nm_i->fcnt > 2 * MAX_FREE_NIDS, stop scanning other NAT entries.
> 
> Signed-off-by: Haicheng Li <haicheng...@linux.intel.com>
> ---
>  fs/f2fs/node.c |   13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 1b45dd0..1fe3fe2 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1254,7 +1254,7 @@ static int add_free_nid(struct f2fs_nm_info *nm_i, 
> nid_t nid)
>       struct free_nid *i;
>  
>       if (nm_i->fcnt > 2 * MAX_FREE_NIDS)
> -             return 0;
> +             return -1;

We should check all the handler of add_free_nid().
So, plz see the below modified patch.

>  
>       /* 0 nid should not be used */
>       if (nid == 0)
> @@ -1302,12 +1302,17 @@ static void scan_nat_page(struct f2fs_nm_info *nm_i,
>       i = start_nid % NAT_ENTRY_PER_BLOCK;
>  
>       for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
> +             int cnt;
> +
>               if (start_nid >= nm_i->max_nid)
>                       break;
> -             blk_addr  = le32_to_cpu(nat_blk->entries[i].block_addr);
> +             blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
>               BUG_ON(blk_addr == NEW_ADDR);
> -             if (blk_addr == NULL_ADDR)
> -                     add_free_nid(nm_i, start_nid);
> +             if (blk_addr == NULL_ADDR) {
> +                     cnt = add_free_nid(nm_i, start_nid);
> +                     if (cnt < 0)
> +                             break;
> +             }

Here we need to eliminate cnt.

>       }
>  }
>  


-----
From e2da02f0ba045f792d166ac8215d04474c06f319 Mon Sep 17 00:00:00 2001
From: Haicheng Li <haicheng...@linux.intel.com>
Date: Mon, 6 May 2013 23:15:43 +0800
Subject: [PATCH] f2fs: optimize scan_nat_page()
Cc: linux-fsde...@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-f2fs-de...@lists.sourceforge.net

When nm_i->fcnt > 2 * MAX_FREE_NIDS, stop scanning other NAT entries.

Signed-off-by: Haicheng Li <haicheng...@linux.intel.com>
[Jaegeuk Kim: fix handling the return value of add_free_nid()]
Signed-off-by: Jaegeuk Kim <jaegeuk....@samsung.com>
---
 fs/f2fs/node.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 122200e..e42934e 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1254,7 +1254,7 @@ static int add_free_nid(struct f2fs_nm_info *nm_i,
nid_t nid)
        struct free_nid *i;
 
        if (nm_i->fcnt > 2 * MAX_FREE_NIDS)
-               return 0;
+               return -1;
 
        /* 0 nid should not be used */
        if (nid == 0)
@@ -1302,12 +1302,16 @@ static void scan_nat_page(struct f2fs_nm_info
*nm_i,
        i = start_nid % NAT_ENTRY_PER_BLOCK;
 
        for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
+
                if (start_nid >= nm_i->max_nid)
                        break;
-               blk_addr  = le32_to_cpu(nat_blk->entries[i].block_addr);
+
+               blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
                BUG_ON(blk_addr == NEW_ADDR);
-               if (blk_addr == NULL_ADDR)
-                       add_free_nid(nm_i, start_nid);
+               if (blk_addr == NULL_ADDR) {
+                       if (add_free_nid(nm_i, start_nid) < 0)
+                               break;
+               }
        }
 }
 
@@ -1655,7 +1659,7 @@ flush_now:
                }
 
                if (nat_get_blkaddr(ne) == NULL_ADDR &&
-                                       !add_free_nid(NM_I(sbi), nid)) {
+                               add_free_nid(NM_I(sbi), nid) <= 0) {
                        write_lock(&nm_i->nat_tree_lock);
                        __del_from_nat_cache(nm_i, ne);
                        write_unlock(&nm_i->nat_tree_lock);
-- 
1.8.1.3.566.gaa39828





-- 
Jaegeuk Kim
Samsung

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