The patch titled
FS-Cache: Avoid ENFILE checking for kernel-specific open files
has been added to the -mm tree. Its filename is
fs-cache-avoid-enfile-checking-for-kernel-specific-open-files.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
From: David Howells <dhowells@xxxxxxxxxx>
Make it possible to avoid ENFILE checking for kernel specific open files, such
as are used by the CacheFiles module.
After, for example, tarring up a kernel source tree over the network, the
CacheFiles module may easily have 20000+ files open in the backing filesystem,
thus causing all non-root processes to be given error ENFILE when they try to
open a file, socket, pipe, etc..
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
Documentation/sysctl/fs.txt | 6 +++-
fs/file_table.c | 48 +++++++++++++++++++++++++++-------
fs/open.c | 20 ++++++++++++++
include/linux/file.h | 1
include/linux/fs.h | 10 +++++++
include/linux/sysctl.h | 1
kernel/sysctl.c | 11 +++++++
7 files changed, 86 insertions(+), 11 deletions(-)
diff -puN Documentation/sysctl/fs.txt~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files Documentation/sysctl/fs.txt
--- devel/Documentation/sysctl/fs.txt~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files 2006-05-11 09:56:24.000000000 -0700
+++ devel-akpm/Documentation/sysctl/fs.txt 2006-05-11 09:56:24.000000000 -0700
@@ -71,7 +71,7 @@ you might want to raise the limit.
==============================================================
-file-max & file-nr:
+file-max, file-nr & file-kernel:
The kernel allocates file handles dynamically, but as yet it
doesn't free them again.
@@ -88,6 +88,10 @@ close to the maximum, but the number of
significantly greater than 0, you've encountered a peak in your
usage of file handles and you don't need to increase the maximum.
+The value in file-kernel denotes the number of internal file handles
+that the kernel has open. These do not contribute to ENFILE
+accounting.
+
==============================================================
inode-max, inode-nr & inode-state:
diff -puN fs/file_table.c~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files fs/file_table.c
--- devel/fs/file_table.c~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files 2006-05-11 09:56:24.000000000 -0700
+++ devel-akpm/fs/file_table.c 2006-05-11 09:56:24.000000000 -0700
@@ -30,10 +30,13 @@ struct files_stat_struct files_stat = {
.max_files = NR_FILE
};
+struct files_kernel_stat_struct files_kernel_stat;
+
/* public. Not pretty! */
__cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock);
static struct percpu_counter nr_files __cacheline_aligned_in_smp;
+static atomic_t nr_kernel_files;
static inline void file_free_rcu(struct rcu_head *head)
{
@@ -43,7 +46,10 @@ static inline void file_free_rcu(struct
static inline void file_free(struct file *f)
{
- percpu_counter_dec(&nr_files);
+ if (f->f_kernel_flags & FKFLAGS_NO_ENFILE)
+ atomic_dec(&nr_kernel_files);
+ else
+ percpu_counter_dec(&nr_files);
call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
}
@@ -74,45 +80,64 @@ int proc_nr_files(ctl_table *table, int
files_stat.nr_files = get_nr_files();
return proc_dointvec(table, write, filp, buffer, lenp, ppos);
}
+int proc_files_kernel(ctl_table *table, int write, struct file *filp,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ files_kernel_stat.nr_kernel_files = atomic_read(&nr_kernel_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;
}
+int proc_files_kernel(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
* we run out of memory.
*/
-struct file *get_empty_filp(void)
+struct file *get_empty_kernel_filp(unsigned short kflags)
{
struct task_struct *tsk;
static int old_max;
struct file * f;
/*
- * Privileged users can go above max_files
+ * Privileged users can go above max_files and internal kernel users
+ * can avoid it completely
*/
- if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) {
+ if (!(kflags & FKFLAGS_NO_ENFILE) &&
+ get_nr_files() >= files_stat.max_files &&
+ !capable(CAP_SYS_ADMIN)
+ ) {
/*
- * percpu_counters are inaccurate. Do an expensive check before
- * we go and fail.
+ * 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);
+ f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
if (f == NULL)
goto fail;
- percpu_counter_inc(&nr_files);
- memset(f, 0, sizeof(*f));
+ if (kflags & FKFLAGS_NO_ENFILE)
+ atomic_inc(&nr_kernel_files);
+ else
+ percpu_counter_inc(&nr_files);
+
if (security_file_alloc(f))
goto fail_sec;
+ f->f_kernel_flags = kflags;
tsk = current;
INIT_LIST_HEAD(&f->f_u.fu_list);
atomic_set(&f->f_count, 1);
@@ -138,6 +163,11 @@ fail:
return NULL;
}
+struct file *get_empty_filp(void)
+{
+ return get_empty_kernel_filp(0);
+}
+
EXPORT_SYMBOL(get_empty_filp);
void fastcall fput(struct file *file)
diff -puN fs/open.c~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files fs/open.c
--- devel/fs/open.c~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files 2006-05-11 09:56:24.000000000 -0700
+++ devel-akpm/fs/open.c 2006-05-11 09:56:24.000000000 -0700
@@ -974,6 +974,26 @@ struct file *dentry_open(struct dentry *
EXPORT_SYMBOL(dentry_open);
/*
+ * open a specifically in-kernel file
+ */
+struct file *dentry_open_kernel(struct dentry *dentry, struct vfsmount *mnt, int flags)
+{
+ int error;
+ struct file *f;
+
+ error = -ENFILE;
+ f = get_empty_kernel_filp(FKFLAGS_NO_ENFILE);
+ if (f == NULL) {
+ dput(dentry);
+ mntput(mnt);
+ return ERR_PTR(error);
+ }
+
+ return __dentry_open(dentry, mnt, flags, f, NULL);
+}
+EXPORT_SYMBOL_GPL(dentry_open_kernel);
+
+/*
* Find an empty file descriptor entry, and mark it busy.
*/
int get_unused_fd(void)
diff -puN include/linux/file.h~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files include/linux/file.h
--- devel/include/linux/file.h~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files 2006-05-11 09:56:24.000000000 -0700
+++ devel-akpm/include/linux/file.h 2006-05-11 09:56:24.000000000 -0700
@@ -79,7 +79,6 @@ extern void FASTCALL(set_close_on_exec(u
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 struct file ** alloc_fd_array(int);
extern void free_fd_array(struct file **, int);
diff -puN include/linux/fs.h~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files include/linux/fs.h
--- devel/include/linux/fs.h~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files 2006-05-11 09:56:24.000000000 -0700
+++ devel-akpm/include/linux/fs.h 2006-05-11 09:56:24.000000000 -0700
@@ -34,7 +34,11 @@ struct files_stat_struct {
int nr_free_files; /* read only */
int max_files; /* tunable */
};
+struct files_kernel_stat_struct {
+ int nr_kernel_files; /* read only */
+};
extern struct files_stat_struct files_stat;
+extern struct files_kernel_stat_struct files_kernel_stat;
extern int get_max_files(void);
struct inodes_stat_t {
@@ -70,6 +74,8 @@ extern int dir_notify_enable;
behavior for cross-node execution/opening_for_writing of files */
#define FMODE_EXEC 16
+#define FKFLAGS_NO_ENFILE 1 /* kernel internal file (ignored for ENFILE accounting) */
+
#define RW_MASK 1
#define RWA_MASK 2
#define READ 0
@@ -640,6 +646,7 @@ struct file {
atomic_t f_count;
unsigned int f_flags;
mode_t f_mode;
+ unsigned short f_kernel_flags;
loff_t f_pos;
struct fown_struct f_owner;
unsigned int f_uid, f_gid;
@@ -1385,6 +1392,7 @@ extern long do_sys_open(int fdf, const c
int mode);
extern struct file *filp_open(const char *, int, int);
extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);
+extern struct file * dentry_open_kernel(struct dentry *, struct vfsmount *, int);
extern int filp_close(struct file *, fl_owner_t id);
extern char * getname(const char __user *);
@@ -1586,6 +1594,7 @@ static inline void insert_inode_hash(str
}
extern struct file * get_empty_filp(void);
+extern struct file * get_empty_kernel_filp(unsigned short fkflags);
extern void file_move(struct file *f, struct list_head *list);
extern void file_kill(struct file *f);
struct bio;
@@ -1611,6 +1620,7 @@ extern ssize_t generic_file_direct_write
unsigned long *, loff_t, loff_t *, size_t, size_t);
extern ssize_t generic_file_buffered_write(struct kiocb *, const struct iovec *,
unsigned long, loff_t, loff_t *, size_t, ssize_t);
+extern int generic_file_buffered_write_one_kernel_page(struct file *, pgoff_t, struct page *);
extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
ssize_t generic_file_write_nolock(struct file *file, const struct iovec *iov,
diff -puN include/linux/sysctl.h~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files include/linux/sysctl.h
--- devel/include/linux/sysctl.h~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files 2006-05-11 09:56:24.000000000 -0700
+++ devel-akpm/include/linux/sysctl.h 2006-05-11 09:56:24.000000000 -0700
@@ -787,6 +787,7 @@ enum
FS_AIO_NR=18, /* current system-wide number of aio requests */
FS_AIO_MAX_NR=19, /* system-wide maximum number of aio requests */
FS_INOTIFY=20, /* inotify submenu */
+ FS_FILE_KERNEL=21, /* int: number of internal kernel files */
};
/* /proc/sys/fs/quota/ */
diff -puN kernel/sysctl.c~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files kernel/sysctl.c
--- devel/kernel/sysctl.c~fs-cache-avoid-enfile-checking-for-kernel-specific-open-files 2006-05-11 09:56:24.000000000 -0700
+++ devel-akpm/kernel/sysctl.c 2006-05-11 09:56:24.000000000 -0700
@@ -53,6 +53,9 @@
extern int proc_nr_files(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos);
+extern int proc_files_kernel(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. */
@@ -956,6 +959,14 @@ static ctl_table fs_table[] = {
.proc_handler = &proc_dointvec,
},
{
+ .ctl_name = FS_FILE_KERNEL,
+ .procname = "file-kernel",
+ .data = &files_stat,
+ .maxlen = 1*sizeof(int),
+ .mode = 0444,
+ .proc_handler = &proc_files_kernel,
+ },
+ {
.ctl_name = FS_DENTRY,
.procname = "dentry-state",
.data = &dentry_stat,
_
Patches currently in -mm which might be from dhowells@xxxxxxxxxx are
fix-can_share_swap_page-when-config_swap.patch
nfs-permit-filesystem-to-override-root-dentry-on-mount.patch
nfs-permit-filesystem-to-perform-statfs-with-a-known-root-dentry.patch
nfs-abstract-out-namespace-initialisation.patch
nfs-add-dentry-materialisation-op.patch
nfs-split-fs-nfs-inodec-into-inode-superblock-and-namespace-bits.patch
nfs-share-nfs-superblocks-per-protocol-per-server-per-fsid.patch
fs-cache-provide-a-filesystem-specific-syncable-page-bit.patch
fs-cache-add-notification-of-page-becoming-writable-to-vma-ops.patch
fs-cache-avoid-enfile-checking-for-kernel-specific-open-files.patch
fs-cache-generic-filesystem-caching-facility.patch
fs-cache-make-kafs-use-fs-cache.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem.patch
fs-cache-release-page-private-in-failed-readahead.patch
nfs-use-local-caching.patch
fix-incorrect-sa_onstack-behaviour-for-64-bit-processes.patch
net-rxrpc-use-list_move.patch
fs-use-list_move.patch
mutex-subsystem-synchro-test-module.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
