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author | Dave Chinner <dchinner@redhat.com> | 2010-10-23 05:03:02 -0400 |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2010-10-25 21:26:09 -0400 |
commit | cffbc8aa334f55c9ed42d25202eb3ebf3a97c195 (patch) | |
tree | dab046695754e2cec1a7ab7a64b236e976d94360 /fs | |
parent | be1a16a0ae29a7c90081a657b64aa51cb1a65a27 (diff) | |
download | kernel_samsung_aries-cffbc8aa334f55c9ed42d25202eb3ebf3a97c195.zip kernel_samsung_aries-cffbc8aa334f55c9ed42d25202eb3ebf3a97c195.tar.gz kernel_samsung_aries-cffbc8aa334f55c9ed42d25202eb3ebf3a97c195.tar.bz2 |
fs: Convert nr_inodes and nr_unused to per-cpu counters
The number of inodes allocated does not need to be tied to the
addition or removal of an inode to/from a list. If we are not tied
to a list lock, we could update the counters when inodes are
initialised or destroyed, but to do that we need to convert the
counters to be per-cpu (i.e. independent of a lock). This means that
we have the freedom to change the list/locking implementation
without needing to care about the counters.
Based on a patch originally from Eric Dumazet.
[AV: cleaned up a bit, fixed build breakage on weird configs
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/fs-writeback.c | 5 | ||||
-rw-r--r-- | fs/inode.c | 64 | ||||
-rw-r--r-- | fs/internal.h | 1 |
3 files changed, 48 insertions, 22 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 39f44f2..f04d04a 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -723,7 +723,7 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb) wb->last_old_flush = jiffies; nr_pages = global_page_state(NR_FILE_DIRTY) + global_page_state(NR_UNSTABLE_NFS) + - (inodes_stat.nr_inodes - inodes_stat.nr_unused); + get_nr_dirty_inodes(); if (nr_pages) { struct wb_writeback_work work = { @@ -1090,8 +1090,7 @@ void writeback_inodes_sb(struct super_block *sb) WARN_ON(!rwsem_is_locked(&sb->s_umount)); - work.nr_pages = nr_dirty + nr_unstable + - (inodes_stat.nr_inodes - inodes_stat.nr_unused); + work.nr_pages = nr_dirty + nr_unstable + get_nr_dirty_inodes(); bdi_queue_work(sb->s_bdi, &work); wait_for_completion(&done); @@ -103,8 +103,41 @@ static DECLARE_RWSEM(iprune_sem); */ struct inodes_stat_t inodes_stat; +static struct percpu_counter nr_inodes __cacheline_aligned_in_smp; +static struct percpu_counter nr_inodes_unused __cacheline_aligned_in_smp; + static struct kmem_cache *inode_cachep __read_mostly; +static inline int get_nr_inodes(void) +{ + return percpu_counter_sum_positive(&nr_inodes); +} + +static inline int get_nr_inodes_unused(void) +{ + return percpu_counter_sum_positive(&nr_inodes_unused); +} + +int get_nr_dirty_inodes(void) +{ + int nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); + return nr_dirty > 0 ? nr_dirty : 0; + +} + +/* + * Handle nr_inode sysctl + */ +#ifdef CONFIG_SYSCTL +int proc_nr_inodes(ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + inodes_stat.nr_inodes = get_nr_inodes(); + inodes_stat.nr_unused = get_nr_inodes_unused(); + return proc_dointvec(table, write, buffer, lenp, ppos); +} +#endif + static void wake_up_inode(struct inode *inode) { /* @@ -192,6 +225,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode) inode->i_fsnotify_mask = 0; #endif + percpu_counter_inc(&nr_inodes); + return 0; out: return -ENOMEM; @@ -232,6 +267,7 @@ void __destroy_inode(struct inode *inode) if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) posix_acl_release(inode->i_default_acl); #endif + percpu_counter_dec(&nr_inodes); } EXPORT_SYMBOL(__destroy_inode); @@ -286,7 +322,7 @@ void __iget(struct inode *inode) if (!(inode->i_state & (I_DIRTY|I_SYNC))) list_move(&inode->i_list, &inode_in_use); - inodes_stat.nr_unused--; + percpu_counter_dec(&nr_inodes_unused); } void end_writeback(struct inode *inode) @@ -327,8 +363,6 @@ static void evict(struct inode *inode) */ static void dispose_list(struct list_head *head) { - int nr_disposed = 0; - while (!list_empty(head)) { struct inode *inode; @@ -344,11 +378,7 @@ static void dispose_list(struct list_head *head) wake_up_inode(inode); destroy_inode(inode); - nr_disposed++; } - spin_lock(&inode_lock); - inodes_stat.nr_inodes -= nr_disposed; - spin_unlock(&inode_lock); } /* @@ -357,7 +387,7 @@ static void dispose_list(struct list_head *head) static int invalidate_list(struct list_head *head, struct list_head *dispose) { struct list_head *next; - int busy = 0, count = 0; + int busy = 0; next = head->next; for (;;) { @@ -383,13 +413,11 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose) list_move(&inode->i_list, dispose); WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; - count++; + percpu_counter_dec(&nr_inodes_unused); continue; } busy = 1; } - /* only unused inodes may be cached with i_count zero */ - inodes_stat.nr_unused -= count; return busy; } @@ -447,7 +475,6 @@ static int can_unuse(struct inode *inode) static void prune_icache(int nr_to_scan) { LIST_HEAD(freeable); - int nr_pruned = 0; int nr_scanned; unsigned long reap = 0; @@ -483,9 +510,8 @@ static void prune_icache(int nr_to_scan) list_move(&inode->i_list, &freeable); WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; - nr_pruned++; + percpu_counter_dec(&nr_inodes_unused); } - inodes_stat.nr_unused -= nr_pruned; if (current_is_kswapd()) __count_vm_events(KSWAPD_INODESTEAL, reap); else @@ -517,7 +543,7 @@ static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask) return -1; prune_icache(nr); } - return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; + return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure; } static struct shrinker icache_shrinker = { @@ -594,7 +620,6 @@ static inline void __inode_add_to_lists(struct super_block *sb, struct hlist_head *head, struct inode *inode) { - inodes_stat.nr_inodes++; list_add(&inode->i_list, &inode_in_use); list_add(&inode->i_sb_list, &sb->s_inodes); if (head) @@ -1214,7 +1239,7 @@ static void iput_final(struct inode *inode) if (!drop) { if (!(inode->i_state & (I_DIRTY|I_SYNC))) list_move(&inode->i_list, &inode_unused); - inodes_stat.nr_unused++; + percpu_counter_inc(&nr_inodes_unused); if (sb->s_flags & MS_ACTIVE) { spin_unlock(&inode_lock); return; @@ -1226,14 +1251,13 @@ static void iput_final(struct inode *inode) spin_lock(&inode_lock); WARN_ON(inode->i_state & I_NEW); inode->i_state &= ~I_WILL_FREE; - inodes_stat.nr_unused--; + percpu_counter_dec(&nr_inodes_unused); hlist_del_init(&inode->i_hash); } list_del_init(&inode->i_list); list_del_init(&inode->i_sb_list); WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; - inodes_stat.nr_inodes--; spin_unlock(&inode_lock); evict(inode); spin_lock(&inode_lock); @@ -1502,6 +1526,8 @@ void __init inode_init(void) SLAB_MEM_SPREAD), init_once); register_shrinker(&icache_shrinker); + percpu_counter_init(&nr_inodes, 0); + percpu_counter_init(&nr_inodes_unused, 0); /* Hash may have been set up in inode_init_early */ if (!hashdist) diff --git a/fs/internal.h b/fs/internal.h index f6dce46..4cc67eb 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -105,4 +105,5 @@ extern void release_open_intent(struct nameidata *); /* * inode.c */ +extern int get_nr_dirty_inodes(void); extern int invalidate_inodes(struct super_block *); |