[PATCH 5/6] f2fs: use percpu_rw_semaphore

From: Jaegeuk Kim
Date: Wed Jul 06 2016 - 12:06:48 EST


This patch replaces rw_semaphore with percpu_rw_semaphore for:
sbi->cp_rwsem
nm_i->nat_tree_lock

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/f2fs.h | 12 ++++++------
fs/f2fs/node.c | 47 ++++++++++++++++++++++++-----------------------
fs/f2fs/super.c | 6 +++++-
3 files changed, 35 insertions(+), 30 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a51f230..2f59888 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -547,7 +547,7 @@ 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 */
- struct rw_semaphore nat_tree_lock; /* protect nat_tree_lock */
+ struct percpu_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 */
@@ -795,7 +795,7 @@ struct f2fs_sb_info {
struct f2fs_checkpoint *ckpt; /* raw checkpoint pointer */
struct inode *meta_inode; /* cache meta blocks */
struct mutex cp_mutex; /* checkpoint procedure lock */
- struct rw_semaphore cp_rwsem; /* blocking FS operations */
+ struct percpu_rw_semaphore cp_rwsem; /* blocking FS operations */
struct rw_semaphore node_write; /* locking node writes */
wait_queue_head_t cp_wait;
unsigned long last_time[MAX_TIME]; /* to store time in jiffies */
@@ -1082,22 +1082,22 @@ static inline void clear_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f)

static inline void f2fs_lock_op(struct f2fs_sb_info *sbi)
{
- down_read(&sbi->cp_rwsem);
+ percpu_down_read(&sbi->cp_rwsem);
}

static inline void f2fs_unlock_op(struct f2fs_sb_info *sbi)
{
- up_read(&sbi->cp_rwsem);
+ percpu_up_read(&sbi->cp_rwsem);
}

static inline void f2fs_lock_all(struct f2fs_sb_info *sbi)
{
- down_write(&sbi->cp_rwsem);
+ percpu_down_write(&sbi->cp_rwsem);
}

static inline void f2fs_unlock_all(struct f2fs_sb_info *sbi)
{
- up_write(&sbi->cp_rwsem);
+ percpu_up_write(&sbi->cp_rwsem);
}

static inline int __get_cp_reason(struct f2fs_sb_info *sbi)
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 9d994b9..b841c43 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -206,14 +206,14 @@ int need_dentry_mark(struct f2fs_sb_info *sbi, nid_t nid)
struct nat_entry *e;
bool need = false;

- down_read(&nm_i->nat_tree_lock);
+ percpu_down_read(&nm_i->nat_tree_lock);
e = __lookup_nat_cache(nm_i, nid);
if (e) {
if (!get_nat_flag(e, IS_CHECKPOINTED) &&
!get_nat_flag(e, HAS_FSYNCED_INODE))
need = true;
}
- up_read(&nm_i->nat_tree_lock);
+ percpu_up_read(&nm_i->nat_tree_lock);
return need;
}

@@ -223,11 +223,11 @@ bool is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid)
struct nat_entry *e;
bool is_cp = true;

- down_read(&nm_i->nat_tree_lock);
+ percpu_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;
- up_read(&nm_i->nat_tree_lock);
+ percpu_up_read(&nm_i->nat_tree_lock);
return is_cp;
}

@@ -237,13 +237,13 @@ bool need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino)
struct nat_entry *e;
bool need_update = true;

- down_read(&nm_i->nat_tree_lock);
+ percpu_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;
- up_read(&nm_i->nat_tree_lock);
+ percpu_up_read(&nm_i->nat_tree_lock);
return need_update;
}

@@ -284,7 +284,7 @@ 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;

- down_write(&nm_i->nat_tree_lock);
+ percpu_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);
@@ -334,7 +334,7 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
set_nat_flag(e, HAS_FSYNCED_INODE, true);
set_nat_flag(e, HAS_LAST_FSYNC, fsync_done);
}
- up_write(&nm_i->nat_tree_lock);
+ percpu_up_write(&nm_i->nat_tree_lock);
}

int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
@@ -342,8 +342,7 @@ int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
struct f2fs_nm_info *nm_i = NM_I(sbi);
int nr = nr_shrink;

- if (!down_write_trylock(&nm_i->nat_tree_lock))
- return 0;
+ percpu_down_write(&nm_i->nat_tree_lock);

while (nr_shrink && !list_empty(&nm_i->nat_entries)) {
struct nat_entry *ne;
@@ -352,7 +351,7 @@ int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
__del_from_nat_cache(nm_i, ne);
nr_shrink--;
}
- up_write(&nm_i->nat_tree_lock);
+ percpu_up_write(&nm_i->nat_tree_lock);
return nr - nr_shrink;
}

@@ -374,13 +373,13 @@ void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info *ni)
ni->nid = nid;

/* Check nat cache */
- down_read(&nm_i->nat_tree_lock);
+ percpu_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);
- up_read(&nm_i->nat_tree_lock);
+ percpu_up_read(&nm_i->nat_tree_lock);
return;
}

@@ -404,11 +403,11 @@ void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info *ni)
node_info_from_raw_nat(ni, &ne);
f2fs_put_page(page, 1);
cache:
- up_read(&nm_i->nat_tree_lock);
+ percpu_up_read(&nm_i->nat_tree_lock);
/* cache nat entry */
- down_write(&nm_i->nat_tree_lock);
+ percpu_down_write(&nm_i->nat_tree_lock);
cache_nat_entry(sbi, nid, &ne);
- up_write(&nm_i->nat_tree_lock);
+ percpu_up_write(&nm_i->nat_tree_lock);
}

/*
@@ -1783,7 +1782,7 @@ void build_free_nids(struct f2fs_sb_info *sbi)
ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), FREE_NID_PAGES,
META_NAT, true);

- down_read(&nm_i->nat_tree_lock);
+ percpu_down_read(&nm_i->nat_tree_lock);

while (1) {
struct page *page = get_current_nat_page(sbi, nid);
@@ -1815,7 +1814,7 @@ void build_free_nids(struct f2fs_sb_info *sbi)
remove_free_nid(nm_i, nid);
}
up_read(&curseg->journal_rwsem);
- up_read(&nm_i->nat_tree_lock);
+ percpu_up_read(&nm_i->nat_tree_lock);

ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nm_i->next_scan_nid),
nm_i->ra_nid_pages, META_NAT, false);
@@ -2204,7 +2203,7 @@ void flush_nat_entries(struct f2fs_sb_info *sbi)
if (!nm_i->dirty_nat_cnt)
return;

- down_write(&nm_i->nat_tree_lock);
+ percpu_down_write(&nm_i->nat_tree_lock);

/*
* if there are no enough space in journal to store dirty nat
@@ -2227,7 +2226,7 @@ void flush_nat_entries(struct f2fs_sb_info *sbi)
list_for_each_entry_safe(set, tmp, &sets, set_list)
__flush_nat_entry_set(sbi, set);

- up_write(&nm_i->nat_tree_lock);
+ percpu_up_write(&nm_i->nat_tree_lock);

f2fs_bug_on(sbi, nm_i->dirty_nat_cnt);
}
@@ -2263,7 +2262,8 @@ 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);
- init_rwsem(&nm_i->nat_tree_lock);
+ if (percpu_init_rwsem(&nm_i->nat_tree_lock))
+ return -ENOMEM;

nm_i->next_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
nm_i->bitmap_size = __bitmap_size(sbi, NAT_BITMAP);
@@ -2320,7 +2320,7 @@ void destroy_node_manager(struct f2fs_sb_info *sbi)
spin_unlock(&nm_i->free_nid_list_lock);

/* destroy nat cache */
- down_write(&nm_i->nat_tree_lock);
+ percpu_down_write(&nm_i->nat_tree_lock);
while ((found = __gang_lookup_nat_cache(nm_i,
nid, NATVEC_SIZE, natvec))) {
unsigned idx;
@@ -2345,8 +2345,9 @@ void destroy_node_manager(struct f2fs_sb_info *sbi)
kmem_cache_free(nat_entry_set_slab, setvec[idx]);
}
}
- up_write(&nm_i->nat_tree_lock);
+ percpu_up_write(&nm_i->nat_tree_lock);

+ percpu_free_rwsem(&nm_i->nat_tree_lock);
kfree(nm_i->nat_bitmap);
sbi->nm_info = NULL;
kfree(nm_i);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index e0a975d..2bac917 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -695,6 +695,8 @@ static void destroy_percpu_info(struct f2fs_sb_info *sbi)
percpu_counter_destroy(&sbi->nr_pages[i]);
percpu_counter_destroy(&sbi->alloc_valid_block_count);
percpu_counter_destroy(&sbi->total_valid_inode_count);
+
+ percpu_free_rwsem(&sbi->cp_rwsem);
}

static void f2fs_put_super(struct super_block *sb)
@@ -1471,6 +1473,9 @@ static int init_percpu_info(struct f2fs_sb_info *sbi)
{
int i, err;

+ if (percpu_init_rwsem(&sbi->cp_rwsem))
+ return -ENOMEM;
+
for (i = 0; i < NR_COUNT_TYPE; i++) {
err = percpu_counter_init(&sbi->nr_pages[i], 0, GFP_KERNEL);
if (err)
@@ -1671,7 +1676,6 @@ try_onemore:
sbi->write_io[i].bio = NULL;
}

- init_rwsem(&sbi->cp_rwsem);
init_waitqueue_head(&sbi->cp_wait);
init_sb_info(sbi);

--
2.8.3