6 files changed, 62 insertions, 37 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index a173bba32666..11dc83092d4a 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1736,7 +1736,7 @@ void __init vfs_caches_init(unsigned long mempages)
                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
 
         filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
-                        SLAB_HWCACHE_ALIGN|SLAB_PANIC, filp_ctor, filp_dtor);
+                        SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
 
         dcache_init(mempages);
         inode_init(mempages);
diff --git a/fs/file_table.c b/fs/file_table.c
index 768b58167543..44fabeaa9415 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -5,6 +5,7 @@
  *  Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
  */
 
+#include <linux/config.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/file.h>
@@ -19,52 +20,67 @@
 #include <linux/capability.h>
 #include <linux/cdev.h>
 #include <linux/fsnotify.h>
+#include <linux/sysctl.h>
+#include <linux/percpu_counter.h>
+
+#include <asm/atomic.h>
 
 /* sysctl tunables... */
 struct files_stat_struct files_stat = {
         .max_files = NR_FILE
 };
 
-EXPORT_SYMBOL(files_stat); /* Needed by unix.o */
-
 /* public. Not pretty! */
- __cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock);
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock);
 
-static DEFINE_SPINLOCK(filp_count_lock);
+static struct percpu_counter nr_files __cacheline_aligned_in_smp;
 
-/* slab constructors and destructors are called from arbitrary
- * context and must be fully threaded - use a local spinlock
- * to protect files_stat.nr_files
- */
-void filp_ctor(void *objp, struct kmem_cache *cachep, unsigned long cflags)
+static inline void file_free_rcu(struct rcu_head *head)
 {
-        if ((cflags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
-            SLAB_CTOR_CONSTRUCTOR) {
-                unsigned long flags;
-                spin_lock_irqsave(&filp_count_lock, flags);
-                files_stat.nr_files++;
-                spin_unlock_irqrestore(&filp_count_lock, flags);
-        }
+        struct file *f =  container_of(head, struct file, f_u.fu_rcuhead);
+        kmem_cache_free(filp_cachep, f);
 }
 
-void filp_dtor(void *objp, struct kmem_cache *cachep, unsigned long dflags)
+static inline void file_free(struct file *f)
 {
-        unsigned long flags;
-        spin_lock_irqsave(&filp_count_lock, flags);
-        files_stat.nr_files--;
-        spin_unlock_irqrestore(&filp_count_lock, flags);
+        percpu_counter_dec(&nr_files);
+        call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
 }
 
-static inline void file_free_rcu(struct rcu_head *head)
+/*
+ * Return the total number of open files in the system
+ */
+static int get_nr_files(void)
 {
-        struct file *f =  container_of(head, struct file, f_u.fu_rcuhead);
-        kmem_cache_free(filp_cachep, f);
+        return percpu_counter_read_positive(&nr_files);
 }
 
-static inline void file_free(struct file *f)
+/*
+ * Return the maximum number of open files in the system
+ */
+int get_max_files(void)
 {
-        call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
+        return files_stat.max_files;
 }
+EXPORT_SYMBOL_GPL(get_max_files);
+
+/*
+ * Handle nr_files sysctl
+ */
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
+int proc_nr_files(ctl_table *table, int write, struct file *filp,
+                     void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        files_stat.nr_files = get_nr_files();
+        return proc_dointvec(table, write, filp, buffer, lenp, ppos);
+}
+#else
+int proc_nr_files(ctl_table *table, int write, struct file *filp,
+                     void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        return -ENOSYS;
+}
+#endif
 
 /* Find an unused file structure and return a pointer to it.
  * Returns NULL, if there are no more free file structures or
@@ -78,14 +94,20 @@ struct file *get_empty_filp(void)
         /*
          * Privileged users can go above max_files
          */
-        if (files_stat.nr_files >= files_stat.max_files &&
-                                !capable(CAP_SYS_ADMIN))
-                goto over;
+        if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) {
+                /*
+                 * percpu_counters are inaccurate.  Do an expensive check before
+                 * we go and fail.
+                 */
+                if (percpu_counter_sum(&nr_files) >= files_stat.max_files)
+                        goto over;
+        }
 
         f = kmem_cache_alloc(filp_cachep, GFP_KERNEL);
         if (f == NULL)
                 goto fail;
 
+        percpu_counter_inc(&nr_files);
         memset(f, 0, sizeof(*f));
         if (security_file_alloc(f))
                 goto fail_sec;
@@ -101,10 +123,10 @@ struct file *get_empty_filp(void)
 
 over:
         /* Ran out of filps - report that */
-        if (files_stat.nr_files > old_max) {
+        if (get_nr_files() > old_max) {
                 printk(KERN_INFO "VFS: file-max limit %d reached\n",
-                                        files_stat.max_files);
-                old_max = files_stat.nr_files;
+                                        get_max_files());
+                old_max = get_nr_files();
         }
         goto fail;
 
@@ -276,4 +298,5 @@ void __init files_init(unsigned long mempages)
         if (files_stat.max_files < NR_FILE)
                 files_stat.max_files = NR_FILE;
         files_defer_init();
+        percpu_counter_init(&nr_files);
 } 
diff --git a/include/linux/file.h b/include/linux/file.h
index 418b6101b59a..9901b850f2e4 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -60,8 +60,6 @@ extern void put_filp(struct file *);
 extern int get_unused_fd(void);
 extern void FASTCALL(put_unused_fd(unsigned int fd));
 struct kmem_cache;
-extern void filp_ctor(void * objp, struct kmem_cache *cachep, unsigned long cflags);
-extern void filp_dtor(void * objp, struct kmem_cache *cachep, unsigned long dflags);
 
 extern struct file ** alloc_fd_array(int);
 extern void free_fd_array(struct file **, int);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0cc34b1c42c9..51c0c93bdf93 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -35,6 +35,7 @@ struct files_stat_struct {
         int max_files;          /* tunable */
 };
 extern struct files_stat_struct files_stat;
+extern int get_max_files(void);
 
 struct inodes_stat_t {
         int nr_inodes;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index de2d9109194e..32b48e8ee36e 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -50,6 +50,9 @@
 #include <asm/uaccess.h>
 #include <asm/processor.h>
 
+extern int proc_nr_files(ctl_table *table, int write, struct file *filp,
+                     void __user *buffer, size_t *lenp, loff_t *ppos);
+
 #if defined(CONFIG_SYSCTL)
 
 /* External variables not in a header file. */
@@ -943,7 +946,7 @@ static ctl_table fs_table[] = {
                 .data           = &files_stat,
                 .maxlen         = 3*sizeof(int),
                 .mode           = 0444,
-                .proc_handler   = &proc_dointvec,
+                .proc_handler   = &proc_nr_files,
         },
         {
                 .ctl_name       = FS_MAXFILE,
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 1b5989b1b670..c323cc6a28b0 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -547,7 +547,7 @@ static struct sock * unix_create1(struct socket *sock)
         struct sock *sk = NULL;
         struct unix_sock *u;
 
-        if (atomic_read(&unix_nr_socks) >= 2*files_stat.max_files)
+        if (atomic_read(&unix_nr_socks) >= 2*get_max_files())
                 goto out;
 
         sk = sk_alloc(PF_UNIX, GFP_KERNEL, &unix_proto, 1);