[patch 27/35] fs: icache split IO and LRU lists

From: npiggin
Date: Mon Oct 18 2010 - 23:59:30 EST


Split inode reclaim and writeback lists in preparation to scale them up
(per-bdi locking for i_io and per-zone locking for i_lru)

Signed-off-by: Nick Piggin <npiggin@xxxxxxxxx>

---
fs/fs-writeback.c | 30 +++++++++++++++++-------------
fs/inode.c | 46 +++++++++++++++++++++++++++-------------------
fs/nilfs2/mdt.c | 3 ++-
include/linux/fs.h | 3 ++-
mm/backing-dev.c | 6 +++---
5 files changed, 51 insertions(+), 37 deletions(-)

Index: linux-2.6/fs/fs-writeback.c
===================================================================
--- linux-2.6.orig/fs/fs-writeback.c 2010-10-19 14:18:59.000000000 +1100
+++ linux-2.6/fs/fs-writeback.c 2010-10-19 14:19:21.000000000 +1100
@@ -173,11 +173,11 @@
if (!list_empty(&wb->b_dirty)) {
struct inode *tail;

- tail = list_entry(wb->b_dirty.next, struct inode, i_list);
+ tail = list_entry(wb->b_dirty.next, struct inode, i_io);
if (time_before(inode->dirtied_when, tail->dirtied_when))
inode->dirtied_when = jiffies;
}
- list_move(&inode->i_list, &wb->b_dirty);
+ list_move(&inode->i_io, &wb->b_dirty);
}

/*
@@ -188,7 +188,7 @@
struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;

assert_spin_locked(&wb_inode_list_lock);
- list_move(&inode->i_list, &wb->b_more_io);
+ list_move(&inode->i_io, &wb->b_more_io);
}

static void inode_sync_complete(struct inode *inode)
@@ -230,14 +230,14 @@

assert_spin_locked(&wb_inode_list_lock);
while (!list_empty(delaying_queue)) {
- inode = list_entry(delaying_queue->prev, struct inode, i_list);
+ inode = list_entry(delaying_queue->prev, struct inode, i_io);
if (older_than_this &&
inode_dirtied_after(inode, *older_than_this))
break;
if (sb && sb != inode->i_sb)
do_sb_sort = 1;
sb = inode->i_sb;
- list_move(&inode->i_list, &tmp);
+ list_move(&inode->i_io, &tmp);
}

/* just one sb in list, splice to dispatch_queue and we're done */
@@ -248,12 +248,12 @@

/* Move inodes from one superblock together */
while (!list_empty(&tmp)) {
- inode = list_entry(tmp.prev, struct inode, i_list);
+ inode = list_entry(tmp.prev, struct inode, i_io);
sb = inode->i_sb;
list_for_each_prev_safe(pos, node, &tmp) {
- inode = list_entry(pos, struct inode, i_list);
+ inode = list_entry(pos, struct inode, i_io);
if (inode->i_sb == sb)
- list_move(&inode->i_list, dispatch_queue);
+ list_move(&inode->i_io, dispatch_queue);
}
}
}
@@ -422,7 +422,11 @@
/*
* The inode is clean
*/
- list_move(&inode->i_list, &inode_unused);
+ list_del_init(&inode->i_io);
+ if (list_empty(&inode->i_lru)) {
+ list_add(&inode->i_lru, &inode_unused);
+ inodes_stat.nr_unused++;
+ }
}
}
inode_sync_complete(inode);
@@ -472,7 +476,7 @@
while (!list_empty(&wb->b_io)) {
long pages_skipped;
struct inode *inode = list_entry(wb->b_io.prev,
- struct inode, i_list);
+ struct inode, i_io);

if (!spin_trylock(&inode->i_lock)) {
spin_unlock(&wb_inode_list_lock);
@@ -558,7 +562,7 @@

while (!list_empty(&wb->b_io)) {
struct inode *inode = list_entry(wb->b_io.prev,
- struct inode, i_list);
+ struct inode, i_io);
struct super_block *sb = inode->i_sb;

if (!pin_sb_for_writeback(sb)) {
@@ -703,7 +707,7 @@
spin_lock(&wb_inode_list_lock);
if (!list_empty(&wb->b_more_io)) {
inode = list_entry(wb->b_more_io.prev,
- struct inode, i_list);
+ struct inode, i_io);
if (!spin_trylock(&inode->i_lock)) {
spin_unlock(&wb_inode_list_lock);
goto retry;
@@ -1029,7 +1033,7 @@

inode->dirtied_when = jiffies;
spin_lock(&wb_inode_list_lock);
- list_move(&inode->i_list, &bdi->wb.b_dirty);
+ list_move(&inode->i_io, &bdi->wb.b_dirty);
spin_unlock(&wb_inode_list_lock);
}
}
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h 2010-10-19 14:19:00.000000000 +1100
+++ linux-2.6/include/linux/fs.h 2010-10-19 14:19:21.000000000 +1100
@@ -727,7 +727,8 @@

struct inode {
struct hlist_bl_node i_hash;
- struct list_head i_list; /* backing dev IO list */
+ struct list_head i_io; /* backing dev IO list */
+ struct list_head i_lru; /* inode LRU list */
struct list_head i_sb_list;
union {
struct list_head i_dentry;
Index: linux-2.6/mm/backing-dev.c
===================================================================
--- linux-2.6.orig/mm/backing-dev.c 2010-10-19 14:18:59.000000000 +1100
+++ linux-2.6/mm/backing-dev.c 2010-10-19 14:19:20.000000000 +1100
@@ -74,11 +74,11 @@

nr_wb = nr_dirty = nr_io = nr_more_io = 0;
spin_lock(&wb_inode_list_lock);
- list_for_each_entry(inode, &wb->b_dirty, i_list)
+ list_for_each_entry(inode, &wb->b_dirty, i_io)
nr_dirty++;
- list_for_each_entry(inode, &wb->b_io, i_list)
+ list_for_each_entry(inode, &wb->b_io, i_io)
nr_io++;
- list_for_each_entry(inode, &wb->b_more_io, i_list)
+ list_for_each_entry(inode, &wb->b_more_io, i_io)
nr_more_io++;
spin_unlock(&wb_inode_list_lock);

Index: linux-2.6/fs/inode.c
===================================================================
--- linux-2.6.orig/fs/inode.c 2010-10-19 14:19:00.000000000 +1100
+++ linux-2.6/fs/inode.c 2010-10-19 14:19:21.000000000 +1100
@@ -34,12 +34,13 @@
* inode_hash_bucket lock protects:
* inode hash table, i_hash
* wb_inode_list_lock protects:
- * inode_in_use, inode_unused, b_io, b_more_io, b_dirty, i_list
+ * inode_in_use, inode_unused, b_io, b_more_io, b_dirty, i_io, i_lru
* inode->i_lock protects:
* i_state
* i_count
* i_hash
- * i_list
+ * i_io
+ * i_lru
* i_sb_list
*
* Ordering:
@@ -327,6 +328,7 @@

void destroy_inode(struct inode *inode)
{
+ BUG_ON(!list_empty(&inode->i_io));
__destroy_inode(inode);
if (inode->i_sb->s_op->destroy_inode)
inode->i_sb->s_op->destroy_inode(inode);
@@ -345,7 +347,8 @@
INIT_HLIST_BL_NODE(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_dentry);
INIT_LIST_HEAD(&inode->i_devices);
- INIT_LIST_HEAD(&inode->i_list);
+ INIT_LIST_HEAD(&inode->i_io);
+ INIT_LIST_HEAD(&inode->i_lru);
INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
spin_lock_init(&inode->i_data.tree_lock);
spin_lock_init(&inode->i_data.i_mmap_lock);
@@ -413,8 +416,8 @@
while (!list_empty(head)) {
struct inode *inode;

- inode = list_first_entry(head, struct inode, i_list);
- list_del_init(&inode->i_list);
+ inode = list_first_entry(head, struct inode, i_lru);
+ list_del_init(&inode->i_lru);

evict(inode);

@@ -445,13 +448,14 @@
invalidate_inode_buffers(inode);
if (!inode->i_count) {
spin_lock(&wb_inode_list_lock);
- list_del(&inode->i_list);
+ list_del_init(&inode->i_io);
+ list_del(&inode->i_lru);
inodes_stat.nr_unused--;
spin_unlock(&wb_inode_list_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
spin_unlock(&inode->i_lock);
- list_add(&inode->i_list, dispose);
+ list_add(&inode->i_lru, dispose);
continue;
}
spin_unlock(&inode->i_lock);
@@ -530,20 +534,20 @@
if (list_empty(&inode_unused))
break;

- inode = list_entry(inode_unused.prev, struct inode, i_list);
+ inode = list_entry(inode_unused.prev, struct inode, i_lru);

if (!spin_trylock(&inode->i_lock)) {
spin_unlock(&wb_inode_list_lock);
goto again;
}
if (inode->i_count || (inode->i_state & ~I_REFERENCED)) {
- list_del_init(&inode->i_list);
+ list_del_init(&inode->i_lru);
spin_unlock(&inode->i_lock);
inodes_stat.nr_unused--;
continue;
}
if (inode->i_state & I_REFERENCED) {
- list_move(&inode->i_list, &inode_unused);
+ list_move(&inode->i_lru, &inode_unused);
inode->i_state &= ~I_REFERENCED;
spin_unlock(&inode->i_lock);
continue;
@@ -556,7 +560,7 @@
*
* We'll try to get it back if it becomes freeable.
*/
- list_move(&inode->i_list, &inode_unused);
+ list_move(&inode->i_lru, &inode_unused);
spin_unlock(&wb_inode_list_lock);
__iget(inode);
spin_unlock(&inode->i_lock);
@@ -567,7 +571,7 @@
iput(inode);
spin_lock(&wb_inode_list_lock);
if (inode == list_entry(inode_unused.next,
- struct inode, i_list)) {
+ struct inode, i_lru)) {
if (spin_trylock(&inode->i_lock)) {
if (can_unuse(inode))
goto freeable;
@@ -577,7 +581,7 @@
continue;
}
freeable:
- list_move(&inode->i_list, &freeable);
+ list_move(&inode->i_lru, &freeable);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
spin_unlock(&inode->i_lock);
@@ -1508,9 +1512,9 @@
if (sb->s_flags & MS_ACTIVE) {
inode->i_state |= I_REFERENCED;
if (!(inode->i_state & (I_DIRTY|I_SYNC)) &&
- list_empty(&inode->i_list)) {
+ list_empty(&inode->i_lru)) {
spin_lock(&wb_inode_list_lock);
- list_add(&inode->i_list, &inode_unused);
+ list_add(&inode->i_lru, &inode_unused);
inodes_stat.nr_unused++;
spin_unlock(&wb_inode_list_lock);
}
@@ -1526,11 +1530,15 @@
inode->i_state &= ~I_WILL_FREE;
__remove_inode_hash(inode);
}
- if (!list_empty(&inode->i_list)) {
+ if (!list_empty(&inode->i_lru)) {
spin_lock(&wb_inode_list_lock);
- list_del_init(&inode->i_list);
- if (!inode->i_state)
- inodes_stat.nr_unused--;
+ list_del_init(&inode->i_lru);
+ inodes_stat.nr_unused--;
+ spin_unlock(&wb_inode_list_lock);
+ }
+ if (!list_empty(&inode->i_io)) {
+ spin_lock(&wb_inode_list_lock);
+ list_del_init(&inode->i_io);
spin_unlock(&wb_inode_list_lock);
}
inode_sb_list_del(inode);
Index: linux-2.6/fs/nilfs2/mdt.c
===================================================================
--- linux-2.6.orig/fs/nilfs2/mdt.c 2010-10-19 14:18:58.000000000 +1100
+++ linux-2.6/fs/nilfs2/mdt.c 2010-10-19 14:19:16.000000000 +1100
@@ -504,7 +504,8 @@
#endif
inode->dirtied_when = 0;

- INIT_LIST_HEAD(&inode->i_list);
+ INIT_LIST_HEAD(&inode->i_io);
+ INIT_LIST_HEAD(&inode->i_lru);
INIT_LIST_HEAD(&inode->i_sb_list);
inode->i_state = 0;
#endif


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