ksm: check and skip page, if it is already scanned
hashtable: introduce a small and naive hashtable

This hashtable implementation is using hlist buckets to provide a simple
hashtable to prevent it from getting reimplemented all over the kernel.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
[ Merging this now, so that subsystems can start applying Sasha's
  patches that use this   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
workqueue: use new hashtable implementation

Switch workqueues to use the new hashtable implementation. This reduces the
amount of generic unrelated code in the workqueues.

This patch depends on d9b482c ("hashtable: introduce a small and naive
hashtable") which was merged in v3.6.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
ARM: smp: Wait just 1 second for other CPU to halt

Currently, the busyloop waiting for a 2nd CPU to stop takes about 4
seconds.  Adjust for the overhead of the loop by looping every 1ms
instead of 1us.

Signed-off-by: Chris Fries <C.Fries@motorola.com>
Reviewed-on: http://gerrit.pcs.mot.com/537864
SLT-Approved: Slta Waiver <sltawvr@motorola.com>
Tested-by: Jira Key <jirakey@motorola.com>
Reviewed-by: Check Patch <CHEKPACH@motorola.com>
Reviewed-by: Klocwork kwcheck <klocwork-kwcheck@sourceforge.mot.com>
Reviewed-by: Igor Kovalenko <cik009@motorola.com>
Reviewed-by: Russell Knize <rknize2@motorola.com>
Submit-Approved: Jira Key <jirakey@motorola.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
sched: Fix double normalization of vruntime

dequeue_entity() is called when p->on_rq and sets se->on_rq = 0
which appears to guarentee that the !se->on_rq condition is met.
If the task has done set_current_state(TASK_INTERRUPTIBLE) without
schedule() the second condition will be met and vruntime will be
incorrectly adjusted twice.

In certain cases this can result in the task's vruntime never increasing
past the vruntime of other tasks on the CFS' run queue, starving them of
CPU time.

This patch changes switched_from_fair() to use !p->on_rq instead of
!se->on_rq.

I'm able to cause a task with a priority of 120 to starve all other
tasks with the same priority on an ARM platform running 3.2.51-rt72
PREEMPT RT by writing one character at time to a serial tty (16550 UART)
in a tight loop. I'm also able to verify making this change corrects the
problem on that platform and kernel version.

Signed-off-by: George McCollister <george.mccollister@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1392767811-28916-1-git-send-email-george.mccollister@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
smp: Fix idle_thread_init() inline stub

idle_thread_init() does not have arguments.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Luis Cruz <ljc2491@gmail.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
smpboot: Remove leftover declaration

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
sched: Remove get_online_cpus() usage

Testing/Modified for 3.4.y from 6acce3ef upstream.

Remove get_online_cpus() usage from the scheduler; there's 4 sites that
use it:

 - sched_init_smp(); where its completely superfluous since we're in
   'early' boot and there simply cannot be any hotplugging.

 - sched_getaffinity(); we already take a raw spinlock to protect the
   task cpus_allowed mask, this disables preemption and therefore
   also stabilizes cpu_online_mask as that's modified using
   stop_machine. However switch to active mask for symmetry with
   sched_setaffinity()/set_cpus_allowed_ptr(). We guarantee active
   mask stability by inserting sync_rcu/sched() into _cpu_down.

 - sched_setaffinity(); we don't appear to need get_online_cpus()
   either, there's two sites where hotplug appears relevant:
    * cpuset_cpus_allowed(); for the !cpuset case we use possible_mask,
      for the cpuset case we hold task_lock, which is a spinlock and
      thus for mainline disables preemption (might cause pain on RT).
    * set_cpus_allowed_ptr(); Holds all scheduler locks and thus has
      preemption properly disabled; also it already deals with hotplug
      races explicitly where it releases them.

 - reinit_sched_domains(); we shouldn't need to hotplug here. In fact,
   this has likely been the thorn in my side, causing mpdecision to
   break on sched_mc_power_savings changes.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(Modified for 3.4.y to include sched_domains())
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
sched: Remove extra put_online_cpus() inside sched_setaffinity()

Commit:

	sched: Remove get_online_cpus() usage

has left one extra put_online_cpus() inside sched_setaffinity(),
remove it to fix the WARN:

   ------------[ cut here ]------------
   WARNING: CPU: 0 PID: 3166 at kernel/cpu.c:84 put_online_cpus+0x43/0x70()
   ...
   [<ffffffff810c3fef>] put_online_cpus+0x43/0x70 [
   [<ffffffff810efd59>] sched_setaffinity+0x7d/0x1f9 [
   ...

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/526DD0EE.1090309@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
sched: Fix endless sync_sched/rcu() loop inside _cpu_down()

Commit:

	sched: Remove get_online_cpus() usage

tries to do sync_sched/rcu() inside _cpu_down() but triggers:

	INFO: task swapper/0:1 blocked for more than 120 seconds.
	...
	[<ffffffff811263dc>] synchronize_rcu+0x2c/0x30
	[<ffffffff81d1bd82>] _cpu_down+0x2b2/0x340
	...

It was caused by that in the rcu boost case we rely on smpboot thread to
finish the rcu callback, which has already been parked before sync in here
and leads to the endless sync_sched/rcu().

This patch exchanges the sequence of smpboot_park_threads() and
sync_sched/rcu() to fix the bug.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5282EDC0.6060003@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
workqueue: fix find_worker_executing_work() brekage from hashtable conversion

commit ("workqueue: use new hashtable implementation") incorrectly
made busy workers hashed by the pointer value of worker instead of
work.  This broke find_worker_executing_work() which in turn broke a
lot of fundamental operations of workqueue - non-reentrancy and
flushing among others.  The flush malfunction triggered warning in
disk event code in Fengguang's automated test.

 write_dev_root_ (3265) used greatest stack depth: 2704 bytes left
 ------------[ cut here ]------------
 WARNING: at /c/kernel-tests/src/stable/block/genhd.c:1574 disk_clear_events+0x\
cf/0x108()
 Hardware name: Bochs
 Modules linked in:
 Pid: 3328, comm: ata_id Not tainted 3.7.0-01930-gbff6343 #1167
 Call Trace:
  [<ffffffff810997c4>] warn_slowpath_common+0x83/0x9c
  [<ffffffff810997f7>] warn_slowpath_null+0x1a/0x1c
  [<ffffffff816aea77>] disk_clear_events+0xcf/0x108
  [<ffffffff811bd8be>] check_disk_change+0x27/0x59
  [<ffffffff822e48e2>] cdrom_open+0x49/0x68b
  [<ffffffff81ab0291>] idecd_open+0x88/0xb7
  [<ffffffff811be58f>] __blkdev_get+0x102/0x3ec
  [<ffffffff811bea08>] blkdev_get+0x18f/0x30f
  [<ffffffff811bebfd>] blkdev_open+0x75/0x80
  [<ffffffff8118f510>] do_dentry_open+0x1ea/0x295
  [<ffffffff8118f5f0>] finish_open+0x35/0x41
  [<ffffffff8119c720>] do_last+0x878/0xa25
  [<ffffffff8119c993>] path_openat+0xc6/0x333
  [<ffffffff8119cf37>] do_filp_open+0x38/0x86
  [<ffffffff81190170>] do_sys_open+0x6c/0xf9
  [<ffffffff8119021e>] sys_open+0x21/0x23
  [<ffffffff82c1c3d9>] system_call_fastpath+0x16/0x1b

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
staging: android: ashmem: Avoid deadlock with mmap/shrink

Both ashmem_mmap and ashmem_shrink take the ashmem_lock. It may
be possible for ashmem_mmap to invoke ashmem_shrink:

-000|mutex_lock(lock = 0x0)
-001|ashmem_shrink(?, sc = 0x0) <--- try to take ashmem_mutex again
-002|shrink_slab(shrink = 0xDA5F1CC0, nr_pages_scanned = 0, lru_pages
-002|=
-002|124)
-003|try_to_free_pages(zonelist = 0x0, ?, ?, ?)
-004|__alloc_pages_nodemask(gfp_mask = 21200, order = 1, zonelist =
-004|0xC11D0940,
-005|new_slab(s = 0xE4841E80, ?, node = -1)
-006|__slab_alloc.isra.43.constprop.50(s = 0xE4841E80, gfpflags =
-006|2148925462, ad
-007|kmem_cache_alloc(s = 0xE4841E80, gfpflags = 208)
-008|shmem_alloc_inode(?)
-009|alloc_inode(sb = 0xE480E800)
-010|new_inode_pseudo(?)
-011|new_inode(?)
-012|shmem_get_inode(sb = 0xE480E800, dir = 0x0, ?, dev = 0, flags =
-012|187)
-013|shmem_file_setup(?, ?, flags = 187)
-014|ashmem_mmap(?, vma = 0xC5D64210) <---- Acquire ashmem_mutex
-015|mmap_region(file = 0xDF8E2C00, addr = 1772974080, len = 233472,
-015|flags = 57,
-016|sys_mmap_pgoff(addr = 0, len = 230400, prot = 3, flags = 1, fd =
-016|157, pgoff
-017|ret_fast_syscall(asm)
-->|exception
-018|NUR:0x40097508(asm)
---|end of frame

Avoid this deadlock by using mutex_trylock in ashmem_shrink; if the mutex
is already held, do not attempt to shrink.

Change-Id: I222bbf55856d5849da813b730de0636c80966c8e
CRs-Fixed: 608832
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
msm: kgsl: Treat 0x0 as valid GPU pagetable physical address

Iommu driver could be allocating a valid GPU pagetable at
physical address 0x0, remove assumption from GPU kernel driver
that 0x0 is invalid pagetable address.

Change-Id: I213c0fbc1d90a13bef83c7d7589ad9e5729771fd
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
mm: vmscan: If kswapd has been running too long, allow it to sleep

Under constant allocation pressure, kswapd can be in the situation where
sleeping_prematurely() will always return true even if kswapd has been
running a long time. Check if kswapd needs to be scheduled.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
mm: slub: Default slub_max_order to 0

To avoid locking and per-cpu overhead, SLUB optimisically uses
high-order allocations up to order-3 by default and falls back to
lower allocations if they fail. While care is taken that the caller
and kswapd take no unusual steps in response to this, there are
further consequences like shrinkers who have to free more objects to
release any memory. There is anecdotal evidence that significant time
is being spent looping in shrinkers with insufficient progress being
made (https://lkml.org/lkml/2011/4/28/361) and keeping kswapd awake.

SLUB is now the default allocator and some bug reports have been
pinned down to SLUB using high orders during operations like
copying large amounts of data. SLUBs use of high-orders benefits
applications that are sized to memory appropriately but this does not
necessarily apply to large file servers or desktops.  This patch
causes SLUB to use order-0 pages like SLAB does by default.
There is further evidence that this keeps kswapd's usage lower
(https://lkml.org/lkml/2011/5/10/383).

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
qcom: mpm-of: fix bug in finding the pending interrupts

When APPS proc wakeup from RPM assisted PC states it reads
the vMPM status register to know the reason for wakeup and
retrigger the interrupts to handle it. Current code is not
caring about actual enabled interrupts in vMPM. Sometimes
this is causing APPS proc unnecessarily triggering the
interrupts which are not raised in the system. Fix this by
considering the enabled interrupts in vMPM before triggering
the interrupts.

CRs-fixed: 623293
Change-Id: Ia793e6d501cac3d85b51ed6e359703239a4b9945
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
msm: mpm-of: set wakeup interrupt as NO_SUSPEND

The MPM wakeup interrupt is used to wakeup the Apps processor from
a system wide low power mode when the GIC isn't operational.

The MPM interrupt is configured as a wakeup interrupt by calling into
irq_set_irq_wake().It also needs to be configured with the
IRQF_NO_SUSPEND to prevent the irq from getting disabled during
suspend_device_irqs() in the suspend path. The interrupt is not
re-enabled until after gic_suspend() is executed as a part of the
syscore_suspend() callback.

If the CPU's idle thread enters RPM assisted power collapse between
suspend_device_irqs() and syscore_suspend, the masking of the RPM wakeup
interrupt could prevent wakeup by RPM.

Change-Id: I0d5f0d7277774ddef6817eac10156f92174ec15f
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>