get rid of NR_OPEN and introduce a sysctl_nr_open

NR_OPEN (historically set to 1024*1024) actually forbids processes to open
more than 1024*1024 handles.

Unfortunatly some production servers hit the not so 'ridiculously high
value' of 1024*1024 file descriptors per process.

Changing NR_OPEN is not considered safe because of vmalloc space potential
exhaust.

This patch introduces a new sysctl (/proc/sys/fs/nr_open) wich defaults to
1024*1024, so that admins can decide to change this limit if their workload
needs it.

[akpm@linux-foundation.org: export it for sparc64]
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index e2799b5fafea890153b2d94acb25a712fe6a2587..5681e2fa1496167e6f876b6dab39e9605597a117 100644 (file)
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1029,6 +1029,14 @@ nr_inodes
 Denotes the  number  of  inodes the system has allocated. This number will
 grow and shrink dynamically.
 
 Denotes the  number  of  inodes the system has allocated. This number will
 grow and shrink dynamically.
 

+nr_open
+-------
+
+Denotes the maximum number of file-handles a process can
+allocate. Default value is 1024*1024 (1048576) which should be
+enough for most machines. Actual limit depends on RLIMIT_NOFILE
+resource limit.
+

 nr_free_inodes
 --------------
 
 nr_free_inodes
 --------------
 

diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt
index aa986a35e9945071abed471776565a2cf4644787..f99254327ae59b59971d979b38cc083d3ac096e5 100644 (file)
--- a/Documentation/sysctl/fs.txt
+++ b/Documentation/sysctl/fs.txt
@@ -23,6 +23,7 @@ Currently, these files are in /proc/sys/fs:
 - inode-max
 - inode-nr
 - inode-state
 - inode-max
 - inode-nr
 - inode-state

+- nr_open

 - overflowuid
 - overflowgid
 - suid_dumpable
 - overflowuid
 - overflowgid
 - suid_dumpable


@@ -91,6 +92,15 @@ usage of file handles and you don't need to increase the maximum.
 
 ==============================================================
 
 
 ==============================================================
 

+nr_open:
+
+This denotes the maximum number of file-handles a process can
+allocate. Default value is 1024*1024 (1048576) which should be
+enough for most machines. Actual limit depends on RLIMIT_NOFILE
+resource limit.
+
+==============================================================
+

 inode-max, inode-nr & inode-state:
 
 As with file handles, the kernel allocates the inode structures
 inode-max, inode-nr & inode-state:
 
 As with file handles, the kernel allocates the inode structures

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index 6413c5f232264dbc9b165489396dbb6987d42351..72f9a619a66d8055b03df676979b0645879c7160 100644 (file)
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -430,7 +430,7 @@ sys_getpagesize(void)
 asmlinkage unsigned long
 sys_getdtablesize(void)
 {
 asmlinkage unsigned long
 sys_getdtablesize(void)
 {

-       return NR_OPEN;
+       return sysctl_nr_open;

 }
 
 /*
 }
 
 /*

diff --git a/arch/mips/kernel/sysirix.c b/arch/mips/kernel/sysirix.c
index 4c477c7ff74a1388c21a85392ed19ac7033cbeec..22fd41e946b28c3d9e2a8a853c4951bcada5b629 100644 (file)
--- a/arch/mips/kernel/sysirix.c
+++ b/arch/mips/kernel/sysirix.c
@@ -356,7 +356,7 @@ asmlinkage int irix_syssgi(struct pt_regs *regs)
                        retval = NGROUPS_MAX;
                        goto out;
                case 5:
                        retval = NGROUPS_MAX;
                        goto out;
                case 5:

-                       retval = NR_OPEN;
+                       retval = sysctl_nr_open;

                        goto out;
                case 6:
                        retval = 1;
                        goto out;
                case 6:
                        retval = 1;

diff --git a/arch/sparc64/kernel/sparc64_ksyms.c b/arch/sparc64/kernel/sparc64_ksyms.c
index 60765e314bd8624dfb1dd94329fd2fb0f59ad7f9..8649635d6d74f67e2b184903c3c1d3241fe3c47b 100644 (file)
--- a/arch/sparc64/kernel/sparc64_ksyms.c
+++ b/arch/sparc64/kernel/sparc64_ksyms.c
@@ -277,6 +277,7 @@ EXPORT_SYMBOL(sys_getpid);
 EXPORT_SYMBOL(sys_geteuid);
 EXPORT_SYMBOL(sys_getuid);
 EXPORT_SYMBOL(sys_getegid);
 EXPORT_SYMBOL(sys_geteuid);
 EXPORT_SYMBOL(sys_getuid);
 EXPORT_SYMBOL(sys_getegid);

+EXPORT_SYMBOL(sysctl_nr_open);

 EXPORT_SYMBOL(sys_getgid);
 EXPORT_SYMBOL(svr4_getcontext);
 EXPORT_SYMBOL(svr4_setcontext);
 EXPORT_SYMBOL(sys_getgid);
 EXPORT_SYMBOL(svr4_getcontext);
 EXPORT_SYMBOL(svr4_setcontext);

diff --git a/arch/sparc64/solaris/fs.c b/arch/sparc64/solaris/fs.c
index 61be597bf43037d3df41bd85997db373f7cbde61..9311bfe4f2f7e98cf6940782e26cabbbc5b4fd0f 100644 (file)
--- a/arch/sparc64/solaris/fs.c
+++ b/arch/sparc64/solaris/fs.c
@@ -624,7 +624,7 @@ asmlinkage int solaris_ulimit(int cmd, int val)
        case 3: /* UL_GMEMLIM */
                return current->signal->rlim[RLIMIT_DATA].rlim_cur;
        case 4: /* UL_GDESLIM */
        case 3: /* UL_GMEMLIM */
                return current->signal->rlim[RLIMIT_DATA].rlim_cur;
        case 4: /* UL_GDESLIM */

-               return NR_OPEN;
+               return sysctl_nr_open;

        }
        return -EINVAL;
 }
        }
        return -EINVAL;
 }

diff --git a/arch/sparc64/solaris/timod.c b/arch/sparc64/solaris/timod.c
index a9d32ceabf26e5bed3c6cf2dc2810a2d94e2a07d..f53123c02c2b6b76f9b687bd1f675753d1342633 100644 (file)
--- a/arch/sparc64/solaris/timod.c
+++ b/arch/sparc64/solaris/timod.c
@@ -859,7 +859,8 @@ asmlinkage int solaris_getmsg(unsigned int fd, u32 arg1, u32 arg2, u32 arg3)
 
        SOLD("entry");
        lock_kernel();
 
        SOLD("entry");
        lock_kernel();

-       if(fd >= NR_OPEN) goto out;
+       if (fd >= sysctl_nr_open)
+               goto out;

 
        fdt = files_fdtable(current->files);
        filp = fdt->fd[fd];
 
        fdt = files_fdtable(current->files);
        filp = fdt->fd[fd];


@@ -927,7 +928,8 @@ asmlinkage int solaris_putmsg(unsigned int fd, u32 arg1, u32 arg2, u32 arg3)
 
        SOLD("entry");
        lock_kernel();
 
        SOLD("entry");
        lock_kernel();

-       if(fd >= NR_OPEN) goto out;
+       if (fd >= sysctl_nr_open)
+               goto out;

 
        fdt = files_fdtable(current->files);
        filp = fdt->fd[fd];
 
        fdt = files_fdtable(current->files);
        filp = fdt->fd[fd];

diff --git a/fs/file.c b/fs/file.c
index c5575de01113eb24aa182c77b35d46d0f0fced48..5110acb1c9ef59bb046a69f79fa601a07218b61a 100644 (file)
--- a/fs/file.c
+++ b/fs/file.c
@@ -24,6 +24,8 @@ struct fdtable_defer {
        struct fdtable *next;
 };
 
        struct fdtable *next;
 };
 

+int sysctl_nr_open __read_mostly = 1024*1024;
+

 /*
  * We use this list to defer free fdtables that have vmalloced
  * sets/arrays. By keeping a per-cpu list, we avoid having to embed
 /*
  * We use this list to defer free fdtables that have vmalloced
  * sets/arrays. By keeping a per-cpu list, we avoid having to embed


@@ -147,8 +149,8 @@ static struct fdtable * alloc_fdtable(unsigned int nr)
        nr /= (1024 / sizeof(struct file *));
        nr = roundup_pow_of_two(nr + 1);
        nr *= (1024 / sizeof(struct file *));
        nr /= (1024 / sizeof(struct file *));
        nr = roundup_pow_of_two(nr + 1);
        nr *= (1024 / sizeof(struct file *));

-       if (nr > NR_OPEN)
-               nr = NR_OPEN;
+       if (nr > sysctl_nr_open)
+               nr = sysctl_nr_open;

 
        fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL);
        if (!fdt)
 
        fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL);
        if (!fdt)


@@ -233,7 +235,7 @@ int expand_files(struct files_struct *files, int nr)
        if (nr < fdt->max_fds)
                return 0;
        /* Can we expand? */
        if (nr < fdt->max_fds)
                return 0;
        /* Can we expand? */

-       if (nr >= NR_OPEN)
+       if (nr >= sysctl_nr_open)

                return -EMFILE;
 
        /* All good, so we try */
                return -EMFILE;
 
        /* All good, so we try */

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 19aab50c3b8eadac84610df78b7bbc5fa5b5a2b7..109734bf6377cb3e8392a51ae597df12025cb8be 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -21,7 +21,7 @@
 
 /* Fixed constants first: */
 #undef NR_OPEN
 
 /* Fixed constants first: */
 #undef NR_OPEN

-#define NR_OPEN (1024*1024)    /* Absolute upper limit on fd num */
+extern int sysctl_nr_open;

 #define INR_OPEN 1024          /* Initial setting for nfile rlimits */
 
 #define BLOCK_SIZE_BITS 10
 #define INR_OPEN 1024          /* Initial setting for nfile rlimits */
 
 #define BLOCK_SIZE_BITS 10

diff --git a/kernel/sys.c b/kernel/sys.c
index 53de35fc82458eeade26a07e9a36f1acfc18b88a..2b8e2daa9d953e3242cf2843cdebc088cf40d9b9 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1472,7 +1472,7 @@ asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
        if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
            !capable(CAP_SYS_RESOURCE))
                return -EPERM;
        if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
            !capable(CAP_SYS_RESOURCE))
                return -EPERM;

-       if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
+       if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)

                return -EPERM;
 
        retval = security_task_setrlimit(resource, &new_rlim);
                return -EPERM;
 
        retval = security_task_setrlimit(resource, &new_rlim);

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 5e2ad5bf88e280fdbc83b61a380909555e121a71..86daaa26d1200c359f8f7c150e1ad5d7ddc1f70d 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1202,6 +1202,14 @@ static struct ctl_table fs_table[] = {
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },

+       {
+               .ctl_name       = CTL_UNNUMBERED,
+               .procname       = "nr_open",
+               .data           = &sysctl_nr_open,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = &proc_dointvec,
+       },

        {
                .ctl_name       = FS_DENTRY,
                .procname       = "dentry-state",
        {
                .ctl_name       = FS_DENTRY,
                .procname       = "dentry-state",