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-rw-r--r--fs/dcache.c2
-rw-r--r--fs/file_table.c87
-rw-r--r--include/linux/file.h2
-rw-r--r--include/linux/fs.h1
-rw-r--r--kernel/sysctl.c5
-rw-r--r--net/unix/af_unix.c2
6 files changed, 62 insertions, 37 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index a173bba..11dc830 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 768b581..44fabea 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 418b610..9901b85 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 0cc34b1..51c0c93 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 de2d910..32b48e8 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 1b5989b..c323cc6 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);
generated by cgit v1.1 at 2024-12-26 17:32:29 +0000