From 9cfe015aa424b3c003baba3841a60dd9b5ad319b Mon Sep 17 00:00:00 2001
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Wed, 6 Feb 2008 01:37:16 -0800
Subject: 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>
---
 kernel/sysctl.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'kernel/sysctl.c')

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 5e2ad5bf88e..86daaa26d12 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1202,6 +1202,14 @@ static struct ctl_table fs_table[] = {
 		.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",
-- 
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