Fix memory leak in cpufreq stats.

When system enters sleep, non-boot CPUs will be disabled.
Cpufreq stats sysfs is created when the CPU is up, but it is not
freed when the CPU is going down. This will cause memory leak.

Signed-off-by: xiaobing tu <xiaobing.tu@intel.com>
Signed-off-by: guifang tang <guifang.tang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
af_unix: dont send SCM_CREDENTIALS by default

Since commit 7361c36c5224 (af_unix: Allow credentials to work across
user and pid namespaces) af_unix performance dropped a lot.

This is because we now take a reference on pid and cred in each write(),
and release them in read(), usually done from another process,
eventually from another cpu. This triggers false sharing.

    10.40%  hackbench  [kernel.kallsyms]   [k] put_pid
     8.60%  hackbench  [kernel.kallsyms]   [k] unix_stream_recvmsg
     7.87%  hackbench  [kernel.kallsyms]   [k] unix_stream_sendmsg
     6.11%  hackbench  [kernel.kallsyms]   [k] do_raw_spin_lock
     4.95%  hackbench  [kernel.kallsyms]   [k] unix_scm_to_skb
     4.87%  hackbench  [kernel.kallsyms]   [k] pid_nr_ns
     4.34%  hackbench  [kernel.kallsyms]   [k] cred_to_ucred
     2.39%  hackbench  [kernel.kallsyms]   [k] unix_destruct_scm
     2.24%  hackbench  [kernel.kallsyms]   [k] sub_preempt_count
     1.75%  hackbench  [kernel.kallsyms]   [k] fget_light
     1.51%  hackbench  [kernel.kallsyms]   [k]
__mutex_lock_interruptible_slowpath
     1.42%  hackbench  [kernel.kallsyms]   [k] sock_alloc_send_pskb

This patch includes SCM_CREDENTIALS information in a af_unix message/skb
only if requested by the sender, [man 7 unix for details how to include
ancillary data using sendmsg() system call]

Note: This might break buggy applications that expected SCM_CREDENTIAL
from an unaware write() system call, and receiver not using SO_PASSCRED
socket option.

If SOCK_PASSCRED is set on source or destination socket, we still
include credentials for mere write() syscalls.

Performance boost in hackbench : more than 50% gain on a 16 thread
machine (2 quad-core cpus, 2 threads per core)

hackbench 20 thread 2000

4.228 sec instead of 9.102 sec

Change-Id: Ic9869cd38631db307c5d3ada97d381d263b84089
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
AF_UNIX: Fix poll blocking problem when reading from a stream socket

poll() call may be blocked by concurrent reading from the same stream
socket.

Signed-off-by: Alexey Moiseytsev <himeraster@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
af_unix: fix EPOLLET regression for stream sockets

Commit 0884d7aa24 (AF_UNIX: Fix poll blocking problem when reading from
a stream socket) added a regression for epoll() in Edge Triggered mode
(EPOLLET)

Appropriate fix is to use skb_peek()/skb_unlink() instead of
skb_dequeue(), and only call skb_unlink() when skb is fully consumed.

This remove the need to requeue a partial skb into sk_receive_queue head
and the extra sk->sk_data_ready() calls that added the regression.

This is safe because once skb is given to sk_receive_queue, it is not
modified by a writer, and readers are serialized by u->readlock mutex.

This also reduce number of spinlock acquisition for small reads or
MSG_PEEK users so should improve overall performance.

Change-Id: I27a737764ae9f9e685090def29bdd4342c1b854b
Reported-by: Nick Mathewson <nickm@freehaven.net>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Alexey Moiseytsev <himeraster@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
af_unix: reduce high order page allocations

unix_dgram_sendmsg() currently builds linear skbs, and this can stress
page allocator with high order page allocations. When memory gets
fragmented, this can eventually fail.

We can try to use order-2 allocations for skb head (SKB_MAX_ALLOC) plus
up to 16 page fragments to lower pressure on buddy allocator.

This patch has no effect on messages of less than 16064 bytes.
(on 64bit arches with PAGE_SIZE=4096)

For bigger messages (from 16065 to 81600 bytes), this patch brings
reliability at the expense of performance penalty because of extra pages
allocations.

netperf -t DG_STREAM -T 0,2 -- -m 16064 -s 200000
->4086040 Messages / 10s

netperf -t DG_STREAM -T 0,2 -- -m 16068 -s 200000
->3901747 Messages / 10s

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
af_unix: speedup /proc/net/unix

/proc/net/unix has quadratic behavior, and can hold unix_table_lock for
a while if high number of unix sockets are alive. (90 ms for 200k
sockets...)

We already have a hash table, so its quite easy to use it.

Problem is unbound sockets are still hashed in a single hash slot
(unix_socket_table[UNIX_HASH_TABLE])

This patch also spreads unbound sockets to 256 hash slots, to speedup
both /proc/net/unix and unix_diag.

Time to read /proc/net/unix with 200k unix sockets :
(time dd if=/proc/net/unix of=/dev/null bs=4k)

before : 520 secs
after : 2 secs

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Change-Id: I533bdebabe0299245b68620d03beff2f12c4d034
zwliew: backport to linux 3.0