android: backport to 2.6.29

android: logger: Add new system log for framework/system log messages

Signed-off-by: San Mehat <san@google.com>

Staging: android: timed_gpio: Properly discard invalid timeout values.

The timed output device never previously checked the return value of sscanf,
resulting in an uninitialized int being passed to enable() if input value
was invalid.

Signed-off-by: Mike Lockwood <lockwood@android.com>

Staging: android: binder: Create dedicated workqueue for binder deferred work

Some drivers flush the global workqueue when closed. This would deadlock if
the last reference to the file was released from the binder.

Change-Id: Ifdabc0b383fecb20836d1bbb9786c632402a14e1
Signed-off-by: Arve Hj

oom: move oom_adj value from task_struct to signal_struct

Currently, OOM logic callflow is here.

    __out_of_memory()
        select_bad_process()            for each task
            badness()                   calculate badness of one task
                oom_kill_process()      search child
                    oom_kill_task()     kill target task and mm shared tasks with it

example, process-A have two thread, thread-A and thread-B and it have very
fat memory and each thread have following oom_adj and oom_score.

     thread-A: oom_adj = OOM_DISABLE, oom_score = 0
     thread-B: oom_adj = 0,           oom_score = very-high

Then, select_bad_process() select thread-B, but oom_kill_task() refuse
kill the task because thread-A have OOM_DISABLE.  Thus __out_of_memory()
call select_bad_process() again.  but select_bad_process() select the same
task.  It mean kernel fall in livelock.

The fact is, select_bad_process() must select killable task.  otherwise
OOM logic go into livelock.

And root cause is, oom_adj shouldn't be per-thread value.  it should be
per-process value because OOM-killer kill a process, not thread.  Thus
This patch moves oomkilladj (now more appropriately named oom_adj) from
struct task_struct to struct signal_struct.  it naturally prevent
select_bad_process() choose wrong task.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lowmemorykiller: Don't try to kill the same pid over and over

  Under certain circumstances, a process can take awhile to
handle a sig-kill (especially if it's in a scheduler group with
a very low share ratio). When this occurs, lowmemkiller returns
to vmscan indicating the process memory has been freed - even
though the process is still waiting to die. Since the memory
hasn't actually freed, lowmemkiller is called again shortly after,
and picks the same process to die; regardless of the fact that
it has already been 'scheduled' to die and the memory has already
been reported to vmscan as having been freed.

  Solution is to check fatal_signal_pending() on the selected
task, and if it's already pending destruction return; indicating
to vmscan that no resources were freed on this pass.

Signed-off-by: San Mehat <san@google.com>

sched: Add a generic notifier when a task struct is about to be freed

This patch adds a notifier which can be used by subsystems that may
be interested in when a task has completely died and is about to
have it's last resource freed.

  The Android lowmemory killer uses this to determine when a task
it has killed has finally given up its goods.

Signed-off-by: San Mehat <san@google.com>

staging: android: lowmemkiller: Substantially reduce overhead during reclaim

This patch optimizes lowmemkiller to not do any work when it has an outstanding
kill-request. This greatly reduces the pressure on the task_list lock
(improving interactivity), as well as improving the vmscan performance
when under heavy memory pressure (by up to 20x in tests).

Note: For this enhancement to work, you need CONFIG_PROFILING

Signed-off-by: San Mehat <san@google.com>

staging: android: lowmemorykiller: Fix task_struct leak

As it turns out, the CONFIG_PROFILING interfaces leak a
task struct if the notifier chain returns NOTIFY_OK.. doh.

This patch reworks lowmemkiller to use the new generic task
free notifier chain.

Signed-off-by: San Mehat <san@google.com>

staging: android: lowmemorykiller: Remove bitrotted codepath

Now that we're murder-synchronous, this code path will never be
called (and if it does, it doesn't tell us anything useful other
than we killed a task that was already being killed by somebody
else but hadn't gotten its' signal yet)

Signed-off-by: San Mehat <san@google.com>

binder: Fix memory corruption via page aliasing

binder_deferred_release was not unmapping the page from the buffer
before freeing it, causing memory corruption.  This only happened
when page(s) had not been freed by binder_update_page_range, which
properly unmaps the pages.

This only happens on architectures with VIPT aliasing.

To reproduce, create a program which opens, mmaps, munmaps, then closes
the binder very quickly.  This should leave a page allocated when the
binder is released.  When binder_deferrred_release is called on the
close, the page will remain mapped to the address in the linear
proc->buffer.  Later, we may map the same physical page to a different
virtual address that has different coloring, and this may cause
aliasing to occur.

PAGE_POISONING will greatly increase your chances of noticing any
problems.

Change-Id: I6941bf212881b8bf846bdfda43d3609c7ae4892e

Signed-off-by: Christopher Lais <chris+android@zenthought.org>