[PATCH 2/3] f2fs: use rw_semaphore for nat entry lock

From: Jaegeuk Kim
Date: Thu Dec 04 2014 - 19:50:09 EST


Previoulsy, we used rwlock for nat_entry lock.
But, now we have a lot of complex operations in set_node_addr.
(e.g., allocating kernel memories, handling radix_trees, and so on)

So, this patches tries to change spinlock to rw_semaphore to give CPUs to other
threads.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/f2fs.h | 2 +-
fs/f2fs/node.c | 52 ++++++++++++++++++++++++++--------------------------
2 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d042813..c873140 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -332,7 +332,7 @@ struct f2fs_nm_info {
/* NAT cache management */
struct radix_tree_root nat_root;/* root of the nat entry cache */
struct radix_tree_root nat_set_root;/* root of the nat set cache */
- rwlock_t nat_tree_lock; /* protect nat_tree_lock */
+ struct rw_semaphore nat_tree_lock; /* protect nat_tree_lock */
struct list_head nat_entries; /* cached nat entry list (clean) */
unsigned int nat_cnt; /* the # of cached nat entries */
unsigned int dirty_nat_cnt; /* total num of nat entries in set */
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index c59341d..b47555f 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -196,11 +196,11 @@ bool is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid)
struct nat_entry *e;
bool is_cp = true;

- read_lock(&nm_i->nat_tree_lock);
+ down_read(&nm_i->nat_tree_lock);
e = __lookup_nat_cache(nm_i, nid);
if (e && !get_nat_flag(e, IS_CHECKPOINTED))
is_cp = false;
- read_unlock(&nm_i->nat_tree_lock);
+ up_read(&nm_i->nat_tree_lock);
return is_cp;
}

@@ -210,11 +210,11 @@ bool has_fsynced_inode(struct f2fs_sb_info *sbi, nid_t ino)
struct nat_entry *e;
bool fsynced = false;

- read_lock(&nm_i->nat_tree_lock);
+ down_read(&nm_i->nat_tree_lock);
e = __lookup_nat_cache(nm_i, ino);
if (e && get_nat_flag(e, HAS_FSYNCED_INODE))
fsynced = true;
- read_unlock(&nm_i->nat_tree_lock);
+ up_read(&nm_i->nat_tree_lock);
return fsynced;
}

@@ -224,13 +224,13 @@ bool need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino)
struct nat_entry *e;
bool need_update = true;

- read_lock(&nm_i->nat_tree_lock);
+ down_read(&nm_i->nat_tree_lock);
e = __lookup_nat_cache(nm_i, ino);
if (e && get_nat_flag(e, HAS_LAST_FSYNC) &&
(get_nat_flag(e, IS_CHECKPOINTED) ||
get_nat_flag(e, HAS_FSYNCED_INODE)))
need_update = false;
- read_unlock(&nm_i->nat_tree_lock);
+ up_read(&nm_i->nat_tree_lock);
return need_update;
}

@@ -258,17 +258,17 @@ static void cache_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid,
{
struct nat_entry *e;
retry:
- write_lock(&nm_i->nat_tree_lock);
+ down_write(&nm_i->nat_tree_lock);
e = __lookup_nat_cache(nm_i, nid);
if (!e) {
e = grab_nat_entry(nm_i, nid);
if (!e) {
- write_unlock(&nm_i->nat_tree_lock);
+ up_write(&nm_i->nat_tree_lock);
goto retry;
}
node_info_from_raw_nat(&e->ni, ne);
}
- write_unlock(&nm_i->nat_tree_lock);
+ up_write(&nm_i->nat_tree_lock);
}

static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
@@ -277,12 +277,12 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
struct f2fs_nm_info *nm_i = NM_I(sbi);
struct nat_entry *e;
retry:
- write_lock(&nm_i->nat_tree_lock);
+ 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);
if (!e) {
- write_unlock(&nm_i->nat_tree_lock);
+ up_write(&nm_i->nat_tree_lock);
goto retry;
}
e->ni = *ni;
@@ -326,7 +326,7 @@ retry:
set_nat_flag(e, HAS_FSYNCED_INODE, true);
set_nat_flag(e, HAS_LAST_FSYNC, fsync_done);
}
- write_unlock(&nm_i->nat_tree_lock);
+ up_write(&nm_i->nat_tree_lock);
}

int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
@@ -336,7 +336,7 @@ int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
if (available_free_memory(sbi, NAT_ENTRIES))
return 0;

- write_lock(&nm_i->nat_tree_lock);
+ down_write(&nm_i->nat_tree_lock);
while (nr_shrink && !list_empty(&nm_i->nat_entries)) {
struct nat_entry *ne;
ne = list_first_entry(&nm_i->nat_entries,
@@ -344,7 +344,7 @@ int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
__del_from_nat_cache(nm_i, ne);
nr_shrink--;
}
- write_unlock(&nm_i->nat_tree_lock);
+ up_write(&nm_i->nat_tree_lock);
return nr_shrink;
}

@@ -367,14 +367,14 @@ void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info *ni)
ni->nid = nid;

/* Check nat cache */
- read_lock(&nm_i->nat_tree_lock);
+ down_read(&nm_i->nat_tree_lock);
e = __lookup_nat_cache(nm_i, nid);
if (e) {
ni->ino = nat_get_ino(e);
ni->blk_addr = nat_get_blkaddr(e);
ni->version = nat_get_version(e);
}
- read_unlock(&nm_i->nat_tree_lock);
+ up_read(&nm_i->nat_tree_lock);
if (e)
return;

@@ -1432,13 +1432,13 @@ static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)

if (build) {
/* do not add allocated nids */
- read_lock(&nm_i->nat_tree_lock);
+ down_read(&nm_i->nat_tree_lock);
ne = __lookup_nat_cache(nm_i, nid);
if (ne &&
(!get_nat_flag(ne, IS_CHECKPOINTED) ||
nat_get_blkaddr(ne) != NULL_ADDR))
allocated = true;
- read_unlock(&nm_i->nat_tree_lock);
+ up_read(&nm_i->nat_tree_lock);
if (allocated)
return 0;
}
@@ -1827,20 +1827,20 @@ static void remove_nats_in_journal(struct f2fs_sb_info *sbi)

raw_ne = nat_in_journal(sum, i);
retry:
- write_lock(&nm_i->nat_tree_lock);
+ down_write(&nm_i->nat_tree_lock);
ne = __lookup_nat_cache(nm_i, nid);
if (ne)
goto found;

ne = grab_nat_entry(nm_i, nid);
if (!ne) {
- write_unlock(&nm_i->nat_tree_lock);
+ up_write(&nm_i->nat_tree_lock);
goto retry;
}
node_info_from_raw_nat(&ne->ni, &raw_ne);
found:
__set_nat_cache_dirty(nm_i, ne);
- write_unlock(&nm_i->nat_tree_lock);
+ up_write(&nm_i->nat_tree_lock);
}
update_nats_in_cursum(sum, -i);
mutex_unlock(&curseg->curseg_mutex);
@@ -1911,10 +1911,10 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
}
raw_nat_from_node_info(raw_ne, &ne->ni);

- write_lock(&NM_I(sbi)->nat_tree_lock);
+ down_write(&NM_I(sbi)->nat_tree_lock);
nat_reset_flag(ne);
__clear_nat_cache_dirty(NM_I(sbi), ne);
- write_unlock(&NM_I(sbi)->nat_tree_lock);
+ up_write(&NM_I(sbi)->nat_tree_lock);

if (nat_get_blkaddr(ne) == NULL_ADDR)
add_free_nid(sbi, nid, false);
@@ -2000,7 +2000,7 @@ static int init_node_manager(struct f2fs_sb_info *sbi)

mutex_init(&nm_i->build_lock);
spin_lock_init(&nm_i->free_nid_list_lock);
- rwlock_init(&nm_i->nat_tree_lock);
+ init_rwsem(&nm_i->nat_tree_lock);

nm_i->next_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
nm_i->bitmap_size = __bitmap_size(sbi, NAT_BITMAP);
@@ -2056,7 +2056,7 @@ void destroy_node_manager(struct f2fs_sb_info *sbi)
spin_unlock(&nm_i->free_nid_list_lock);

/* destroy nat cache */
- write_lock(&nm_i->nat_tree_lock);
+ down_write(&nm_i->nat_tree_lock);
while ((found = __gang_lookup_nat_cache(nm_i,
nid, NATVEC_SIZE, natvec))) {
unsigned idx;
@@ -2065,7 +2065,7 @@ void destroy_node_manager(struct f2fs_sb_info *sbi)
__del_from_nat_cache(nm_i, natvec[idx]);
}
f2fs_bug_on(sbi, nm_i->nat_cnt);
- write_unlock(&nm_i->nat_tree_lock);
+ up_write(&nm_i->nat_tree_lock);

kfree(nm_i->nat_bitmap);
sbi->nm_info = NULL;
--
2.1.1

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