EHCI 1.1 addendum introduced several energy efficiency extensions for
EHCI USB host controllers:
1. LPM (link power management)
2. Per-port change
3. Shorter periodic frame list
4. Hardware prefetching

This patch is intended to define the HW bits and debug interface for
EHCI 1.1 addendum. The LPM and Per-port change patches will be sent out
after this patch.
Signed-off-by: NJacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: NAlek Du <alek.du@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

otg_io_write() function does not follow the declaration of
struct otg_io_access_ops.
Signed-off-by: NIgor Grinberg <grinberg@compulab.co.il>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1390) fixes a problem that crops up when a UHCI host
controller is unbound from uhci-hcd while there are still some active
URBs.  The URBs have to be unlinked when the root hub is unregistered,
and uhci-hcd relies upon root-hub status polls as part of its
unlinking procedure.  But usb_hcd_poll_rh_status() won't make those
status calls if hcd->rh_registered is clear, and the flag is cleared
_before_ the unregistration takes place.

Since hcd->rh_registered is used for other things and needs to be
cleared early, the solution is to add a new flag (rh_pollable) and use
it instead.  It gets cleared _after_ the root hub is unregistered.

Now that the status polls don't end too soon, we have to make sure
they also don't occur too late -- after the root hub's usb_device
structure or the HCD's private structures are deallocated.  Therefore
the patch adds usb_get_device() and usb_put_device() calls to protect
the root hub structure, and it adds an extra del_timer_sync() to
prevent the root-hub timer from causing an unexpected status poll.

This additional complexity would not be needed if the HCD framework
had provided separate stop() and release() callbacks instead of just
stop().  This lack could be fixed at some future time (although it
would require changes to every host controller driver); when that
happens this patch won't be needed any more.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Getting and putting arrays of pointers with flex arrays is a PITA.  You
have to remember to pass &ptr to the _put and you have to do weird and
wacky casting to get the ptr back from the _get.  Add two functions
flex_array_get_ptr() and flex_array_put_ptr() to handle all of the magic.

[akpm@linux-foundation.org: simplification suggested by Joe]
Signed-off-by: NEric Paris <eparis@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: James Morris <jmorris@namei.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A profile of a network benchmark showed iommu_num_pages rather high up:

     0.52%  iommu_num_pages

Looking at the profile, an integer divide is taking almost all of the time:

      %
         :      c000000000376ea4 <.iommu_num_pages>:
    1.93 :      c000000000376ea4:       fb e1 ff f8     std     r31,-8(r1)
    0.00 :      c000000000376ea8:       f8 21 ff c1     stdu    r1,-64(r1)
    0.00 :      c000000000376eac:       7c 3f 0b 78     mr      r31,r1
    3.86 :      c000000000376eb0:       38 84 ff ff     addi    r4,r4,-1
    0.00 :      c000000000376eb4:       38 05 ff ff     addi    r0,r5,-1
    0.00 :      c000000000376eb8:       7c 84 2a 14     add     r4,r4,r5
   46.95 :      c000000000376ebc:       7c 00 18 38     and     r0,r0,r3
   45.66 :      c000000000376ec0:       7c 84 02 14     add     r4,r4,r0
    0.00 :      c000000000376ec4:       7c 64 2b 92     divdu   r3,r4,r5
    0.00 :      c000000000376ec8:       38 3f 00 40     addi    r1,r31,64
    0.00 :      c000000000376ecc:       eb e1 ff f8     ld      r31,-8(r1)
    1.61 :      c000000000376ed0:       4e 80 00 20     blr

Since every caller of iommu_num_pages passes in a constant power of two
we can inline this such that the divide is replaced by a shift. The
entire function is only a few instructions once optimised, so it is
a good candidate for inlining overall.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are no more uses of NIPQUAD or NIPQUAD_FMT.  Remove the definitions.
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We should use the __same_type() helper in __must_be_array().
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On some SoC chips, HW resources may be in use during any particular idle
period.  As a consequence, the cpuidle states that the SoC is safe to
enter can change from idle period to idle period.  In addition, the
latency and threshold of each cpuidle state can vary, depending on the
operating condition when the CPU becomes idle, e.g.  the current cpu
frequency, the current state of the HW blocks, etc.

cpuidle core and the menu governor, in the current form, are geared
towards cpuidle states that are static, i.e.  the availabiltiy of the
states, their latencies, their thresholds are non-changing during run
time.  cpuidle does not provide any hook that cpuidle drivers can use to
adjust those values on the fly for the current idle period before the menu
governor selects the target cpuidle state.

This patch extends cpuidle core and the menu governor to handle states
that are dynamic.  There are three additions in the patch and the patch
maintains backwards-compatibility with existing cpuidle drivers.

1) add prepare() to struct cpuidle_device.  A cpuidle driver can hook
   into the callback and cpuidle will call prepare() before calling the
   governor's select function.  The callback gives the cpuidle driver a
   chance to update the dynamic information of the cpuidle states for the
   current idle period, e.g.  state availability, latencies, thresholds,
   power values, etc.

2) add CPUIDLE_FLAG_IGNORE as one of the state flags.  In the prepare()
   function, a cpuidle driver can set/clear the flag to indicate to the
   menu governor whether a cpuidle state should be ignored, i.e.  not
   available, during the current idle period.

3) add power_specified bit to struct cpuidle_device.  The menu governor
   currently assumes that the cpuidle states are arranged in the order of
   increasing latency, threshold, and power savings.  This is true or can
   be made true for static states.  Once the state parameters are dynamic,
   the latencies, thresholds, and power savings for the cpuidle states can
   increase or decrease by different amounts from idle period to idle
   period.  So the assumption of increasing latency, threshold, and power
   savings from Cn to C(n+1) can no longer be guaranteed.

It can be straightforward to calculate the power consumption of each
available state and to specify it in power_usage for the idle period.
Using the power_usage fields, the menu governor then selects the state
that has the lowest power consumption and that still satisfies all other
critieria.  The power_specified bit defaults to 0.  For existing cpuidle
drivers, cpuidle detects that power_specified is 0 and fills in a dummy
set of power_usage values.
Signed-off-by: NAi Li <aili@codeaurora.org>
Cc: Len Brown <len.brown@intel.com>
Acked-by: NArjan van de Ven <arjan@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When taking a memory snapshot in hibernate_snapshot(), all (directly
called) memory allocations use GFP_ATOMIC.  Hence swap misusage during
hibernation never occurs.

But from a pessimistic point of view, there is no guarantee that no page
allcation has __GFP_WAIT.  It is better to have a global indication "we
enter hibernation, don't use swap!".

This patch tries to freeze new-swap-allocation during hibernation.  (All
user processes are frozenm so swapin is not a concern).

This way, no updates will happen to swap_map[] between
hibernate_snapshot() and save_image().  Swap is thawed when swsusp_free()
is called.  We can be assured that swap corruption will not occur.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Hugh Dickins <hughd@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ondrej Zary <linux@rainbow-software.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On swapin it is fairly common for a page to be owned exclusively by one
process.  In that case we want to add the page to the anon_vma of that
process's VMA, instead of to the root anon_vma.

This will reduce the amount of rmap searching that the swapout code needs
to do.
Signed-off-by: NRik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

/proc/pid/oom_adj is now deprecated so that that it may eventually be
removed.  The target date for removal is August 2012.

A warning will be printed to the kernel log if a task attempts to use this
interface.  Future warning will be suppressed until the kernel is rebooted
to prevent spamming the kernel log.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This a complete rewrite of the oom killer's badness() heuristic which is
used to determine which task to kill in oom conditions.  The goal is to
make it as simple and predictable as possible so the results are better
understood and we end up killing the task which will lead to the most
memory freeing while still respecting the fine-tuning from userspace.

Instead of basing the heuristic on mm->total_vm for each task, the task's
rss and swap space is used instead.  This is a better indication of the
amount of memory that will be freeable if the oom killed task is chosen
and subsequently exits.  This helps specifically in cases where KDE or
GNOME is chosen for oom kill on desktop systems instead of a memory
hogging task.

The baseline for the heuristic is a proportion of memory that each task is
currently using in memory plus swap compared to the amount of "allowable"
memory.  "Allowable," in this sense, means the system-wide resources for
unconstrained oom conditions, the set of mempolicy nodes, the mems
attached to current's cpuset, or a memory controller's limit.  The
proportion is given on a scale of 0 (never kill) to 1000 (always kill),
roughly meaning that if a task has a badness() score of 500 that the task
consumes approximately 50% of allowable memory resident in RAM or in swap
space.

The proportion is always relative to the amount of "allowable" memory and
not the total amount of RAM systemwide so that mempolicies and cpusets may
operate in isolation; they shall not need to know the true size of the
machine on which they are running if they are bound to a specific set of
nodes or mems, respectively.

Root tasks are given 3% extra memory just like __vm_enough_memory()
provides in LSMs.  In the event of two tasks consuming similar amounts of
memory, it is generally better to save root's task.

Because of the change in the badness() heuristic's baseline, it is also
necessary to introduce a new user interface to tune it.  It's not possible
to redefine the meaning of /proc/pid/oom_adj with a new scale since the
ABI cannot be changed for backward compatability.  Instead, a new tunable,
/proc/pid/oom_score_adj, is added that ranges from -1000 to +1000.  It may
be used to polarize the heuristic such that certain tasks are never
considered for oom kill while others may always be considered.  The value
is added directly into the badness() score so a value of -500, for
example, means to discount 50% of its memory consumption in comparison to
other tasks either on the system, bound to the mempolicy, in the cpuset,
or sharing the same memory controller.

/proc/pid/oom_adj is changed so that its meaning is rescaled into the
units used by /proc/pid/oom_score_adj, and vice versa.  Changing one of
these per-task tunables will rescale the value of the other to an
equivalent meaning.  Although /proc/pid/oom_adj was originally defined as
a bitshift on the badness score, it now shares the same linear growth as
/proc/pid/oom_score_adj but with different granularity.  This is required
so the ABI is not broken with userspace applications and allows oom_adj to
be deprecated for future removal.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since 2.6.28 zone->prev_priority is unused. Then it can be removed
safely. It reduce stack usage slightly.

Now I have to say that I'm sorry. 2 years ago, I thought prev_priority
can be integrate again, it's useful. but four (or more) times trying
haven't got good performance number. Thus I give up such approach.

The rest of this changelog is notes on prev_priority and why it existed in
the first place and why it might be not necessary any more. This information
is based heavily on discussions between Andrew Morton, Rik van Riel and
Kosaki Motohiro who is heavily quotes from.

Historically prev_priority was important because it determined when the VM
would start unmapping PTE pages. i.e. there are no balances of note within
the VM, Anon vs File and Mapped vs Unmapped. Without prev_priority, there
is a potential risk of unnecessarily increasing minor faults as a large
amount of read activity of use-once pages could push mapped pages to the
end of the LRU and get unmapped.

There is no proof this is still a problem but currently it is not considered
to be. Active files are not deactivated if the active file list is smaller
than the inactive list reducing the liklihood that file-mapped pages are
being pushed off the LRU and referenced executable pages are kept on the
active list to avoid them getting pushed out by read activity.

Even if it is a problem, prev_priority prev_priority wouldn't works
nowadays. First of all, current vmscan still a lot of UP centric code. it
expose some weakness on some dozens CPUs machine. I think we need more and
more improvement.

The problem is, current vmscan mix up per-system-pressure, per-zone-pressure
and per-task-pressure a bit. example, prev_priority try to boost priority to
other concurrent priority. but if the another task have mempolicy restriction,
it is unnecessary, but also makes wrong big latency and exceeding reclaim.
per-task based priority + prev_priority adjustment make the emulation of
per-system pressure. but it have two issue 1) too rough and brutal emulation
2) we need per-zone pressure, not per-system.

Another example, currently DEF_PRIORITY is 12. it mean the lru rotate about
2 cycle (1/4096 + 1/2048 + 1/1024 + .. + 1) before invoking OOM-Killer.
but if 10,0000 thrreads enter DEF_PRIORITY reclaim at the same time, the
system have higher memory pressure than priority==0 (1/4096*10,000 > 2).
prev_priority can't solve such multithreads workload issue. In other word,
prev_priority concept assume the sysmtem don't have lots threads."
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NRik van Riel <riel@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We try to avoid livelocks of writeback when some steadily creates dirty
pages in a mapping we are writing out.  For memory-cleaning writeback,
using nr_to_write works reasonably well but we cannot really use it for
data integrity writeback.  This patch tries to solve the problem.

The idea is simple: Tag all pages that should be written back with a
special tag (TOWRITE) in the radix tree.  This can be done rather quickly
and thus livelocks should not happen in practice.  Then we start doing the
hard work of locking pages and sending them to disk only for those pages
that have TOWRITE tag set.

Note: Adding new radix tree tag grows radix tree node from 288 to 296
bytes for 32-bit archs and from 552 to 560 bytes for 64-bit archs.
However, the number of slab/slub items per page remains the same (13 and 7
respectively).
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement function for setting one tag if another tag is set for each item
in given range.
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The new anon-vma code, was suboptimal and it lead to erratic invocation of
ksm_does_need_to_copy.  That leads to host hangs or guest vnc lockup, or
weird behavior.  It's unclear why ksm_does_need_to_copy is unstable but
the point is that when KSM is not in use, ksm_does_need_to_copy must never
run or we bounce pages for no good reason.  I suspect the same hangs will
happen with KVM swaps.  But this at least fixes the regression in the
new-anon-vma code and it only let KSM bugs triggers when KSM is in use.

The code in do_swap_page likely doesn't cope well with a not-swapcache,
especially the memcg code.
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NRik van Riel <riel@redhat.com>
Cc: Izik Eidus <ieidus@yahoo.com>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current implementation of tmpfs is not scalable.  We found that
stat_lock is contended by multiple threads when we need to get a new page,
leading to useless spinning inside this spin lock.

This patch makes use of the percpu_counter library to maintain local count
of used blocks to speed up getting and returning of pages.  So the
acquisition of stat_lock is unnecessary for getting and returning blocks,
improving the performance of tmpfs on system with large number of cpus.
On a 4 socket 32 core NHM-EX system, we saw improvement of 270%.

The implementation below has a slight chance of race between threads
causing a slight overshoot of the maximum configured blocks.  However, any
overshoot is small, and is bounded by the number of cpus.  This happens
when the number of used blocks is slightly below the maximum configured
blocks when a thread checks the used block count, and another thread
allocates the last block before the current thread does.  This should not
be a problem for tmpfs, as the overshoot is most likely to be a few blocks
and bounded.  If a strict limit is really desired, then configured the max
blocks to be the limit less the number of cpus in system.
Signed-off-by: NTim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add percpu_counter_compare that allows for a quick but accurate comparison
of percpu_counter with a given value.

A rough count is provided by the count field in percpu_counter structure,
without accounting for the other values stored in individual cpu counters.

The actual count is a sum of count and the cpu counters.  However, count
field is never different from the actual value by a factor of
batch*num_online_cpu.  We do not need to get actual count for comparison
if count is different from the given value by this factor and allows for
quick comparison without summing up all the per cpu counters.
Signed-off-by: NTim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

No real bugs, just some dead code and some fixups.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Avoid quite a lot of warnings in header files in a gcc 4.6 -Wall builds
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Define stubs for the numa_*_id() generic percpu related functions for
non-NUMA configurations in <asm-generic/topology.h> where the other
non-numa stubs live.

Fixes ia64 !NUMA build breakage -- e.g., tiger_defconfig

Back out now unneeded '#ifndef CONFIG_NUMA' guards from ia64 smpboot.c
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Tested-by: NTony Luck <tony.luck@intel.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

get_zone_counts() was dropped from kernel tree, see:
http://www.mail-archive.com/mm-commits@vger.kernel.org/msg07313.html but
its prototype remains.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have been used naming try_set_zone_oom and clear_zonelist_oom.
The role of functions is to lock of zonelist for preventing parallel
OOM. So clear_zonelist_oom makes sense but try_set_zone_oome is rather
awkward and unmatched with clear_zonelist_oom.

Let's change it with try_set_zonelist_oom.
Signed-off-by: NMinchan Kim <minchan.kim@gmail.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The three oom killer sysctl variables (sysctl_oom_dump_tasks,
sysctl_oom_kill_allocating_task, and sysctl_panic_on_oom) are better
declared in include/linux/oom.h rather than kernel/sysctl.c.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are various points in the oom killer where the kernel must determine
whether to panic or not.  It's better to extract this to a helper function
to remove all the confusion as to its semantics.

Also fix a call to dump_header() where tasklist_lock is not read- locked,
as required.

There's no functional change with this patch.
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The oom killer presently kills current whenever there is no more memory
free or reclaimable on its mempolicy's nodes.  There is no guarantee that
current is a memory-hogging task or that killing it will free any
substantial amount of memory, however.

In such situations, it is better to scan the tasklist for nodes that are
allowed to allocate on current's set of nodes and kill the task with the
highest badness() score.  This ensures that the most memory-hogging task,
or the one configured by the user with /proc/pid/oom_adj, is always
selected in such scenarios.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The comment suggests that when b_count equals zero it is calling
__wait_no_buffer to trigger some debug, but as there is no debug in
__wait_on_buffer the whole thing is redundant.

AFAICT from the git log this has been the case for at least 5 years, so
it seems safe just to remove this.
Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

KSM reference counts can cause an anon_vma to exist after the processe it
belongs to have already exited.  Because the anon_vma lock now lives in
the root anon_vma, we need to ensure that the root anon_vma stays around
until after all the "child" anon_vmas have been freed.

The obvious way to do this is to have a "child" anon_vma take a reference
to the root in anon_vma_fork.  When the anon_vma is freed at munmap or
process exit, we drop the refcount in anon_vma_unlink and possibly free
the root anon_vma.

The KSM anon_vma reference count function also needs to be modified to
deal with the possibility of freeing 2 levels of anon_vma.  The easiest
way to do this is to break out the KSM magic and make it generic.

When compiling without CONFIG_KSM, this code is compiled out.
Signed-off-by: NRik van Riel <riel@redhat.com>
Tested-by: NLarry Woodman <lwoodman@redhat.com>
Acked-by: NLarry Woodman <lwoodman@redhat.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Tested-by: NDave Young <hidave.darkstar@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Always (and only) lock the root (oldest) anon_vma whenever we do something
in an anon_vma.  The recently introduced anon_vma scalability is due to
the rmap code scanning only the VMAs that need to be scanned.  Many common
operations still took the anon_vma lock on the root anon_vma, so always
taking that lock is not expected to introduce any scalability issues.

However, always taking the same lock does mean we only need to take one
lock, which means rmap_walk on pages from any anon_vma in the vma is
excluded from occurring during an munmap, expand_stack or other operation
that needs to exclude rmap_walk and similar functions.

Also add the proper locking to vma_adjust.
Signed-off-by: NRik van Riel <riel@redhat.com>
Tested-by: NLarry Woodman <lwoodman@redhat.com>
Acked-by: NLarry Woodman <lwoodman@redhat.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Track the root (oldest) anon_vma in each anon_vma tree.  Because we only
take the lock on the root anon_vma, we cannot use the lock on higher-up
anon_vmas to lock anything.  This makes it impossible to do an indirect
lookup of the root anon_vma, since the data structures could go away from
under us.

However, a direct pointer is safe because the root anon_vma is always the
last one that gets freed on munmap or exit, by virtue of the same_vma list
order and unlink_anon_vmas walking the list forward.

[akpm@linux-foundation.org: fix typo]
Signed-off-by: NRik van Riel <riel@redhat.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: NLarry Woodman <lwoodman@redhat.com>
Acked-by: NLarry Woodman <lwoodman@redhat.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Subsitute a direct call of spin_lock(anon_vma->lock) with an inline
function doing exactly the same.

This makes it easier to do the substitution to the root anon_vma lock in a
following patch.

We will deal with the handful of special locks (nested, dec_and_lock, etc)
separately.
Signed-off-by: NRik van Riel <riel@redhat.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: NLarry Woodman <lwoodman@redhat.com>
Acked-by: NLarry Woodman <lwoodman@redhat.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rename anon_vma_lock to vma_lock_anon_vma.  This matches the naming style
used in page_lock_anon_vma and will come in really handy further down in
this patch series.
Signed-off-by: NRik van Riel <riel@redhat.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: NLarry Woodman <lwoodman@redhat.com>
Acked-by: NLarry Woodman <lwoodman@redhat.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kunmap_atomic() is currently at level -4 on Rusty's "Hard To Misuse"
list[1] ("Follow common convention and you'll get it wrong"), except in
some architectures when CONFIG_DEBUG_HIGHMEM is set[2][3].

kunmap() takes a pointer to a struct page; kunmap_atomic(), however, takes
takes a pointer to within the page itself.  This seems to once in a while
trip people up (the convention they are following is the one from
kunmap()).

Make it much harder to misuse, by moving it to level 9 on Rusty's list[4]
("The compiler/linker won't let you get it wrong").  This is done by
refusing to build if the type of its first argument is a pointer to a
struct page.

The real kunmap_atomic() is renamed to kunmap_atomic_notypecheck()
(which is what you would call in case for some strange reason calling it
with a pointer to a struct page is not incorrect in your code).

The previous version of this patch was compile tested on x86-64.

[1] http://ozlabs.org/~rusty/index.cgi/tech/2008-04-01.html
[2] In these cases, it is at level 5, "Do it right or it will always
    break at runtime."
[3] At least mips and powerpc look very similar, and sparc also seems to
    share a common ancestor with both; there seems to be quite some
    degree of copy-and-paste coding here. The include/asm/highmem.h file
    for these three archs mention x86 CPUs at its top.
[4] http://ozlabs.org/~rusty/index.cgi/tech/2008-03-30.html
[5] As an aside, could someone tell me why mn10300 uses unsigned long as
    the first parameter of kunmap_atomic() instead of void *?
Signed-off-by: NCesar Eduardo Barros <cesarb@cesarb.net>
Cc: Russell King <linux@arm.linux.org.uk> (arch/arm)
Cc: Ralf Baechle <ralf@linux-mips.org> (arch/mips)
Cc: David Howells <dhowells@redhat.com> (arch/frv, arch/mn10300)
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> (arch/mn10300)
Cc: Kyle McMartin <kyle@mcmartin.ca> (arch/parisc)
Cc: Helge Deller <deller@gmx.de> (arch/parisc)
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> (arch/parisc)
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> (arch/powerpc)
Cc: Paul Mackerras <paulus@samba.org> (arch/powerpc)
Cc: "David S. Miller" <davem@davemloft.net> (arch/sparc)
Cc: Thomas Gleixner <tglx@linutronix.de> (arch/x86)
Cc: Ingo Molnar <mingo@redhat.com> (arch/x86)
Cc: "H. Peter Anvin" <hpa@zytor.com> (arch/x86)
Cc: Arnd Bergmann <arnd@arndb.de> (include/asm-generic)
Cc: Rusty Russell <rusty@rustcorp.com.au> ("Hard To Misuse" list)
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If sget() finds a matching superblock being set up, it'll
grab an active reference to it and grab s_umount.  That's
fine - we'll wait for completion of foofs_get_sb() that way.
However, if said foofs_get_sb() fails we'll end up holding
the halfway-created superblock.  deactivate_locked_super()
called by foofs_get_sb() will just unlock the sucker since
we are holding another active reference to it.

What we need is a way to tell if superblock has been successfully
set up.  Unfortunately, neither ->s_root nor the check for
MS_ACTIVE quite fit.  Cheap and easy way, suitable for backport:
new flag set by the (only) caller of ->get_sb().  If that flag
isn't present by the time sget() grabbed s_umount on preexisting
superblock it has found, it's seeing a stillborn and should
just bury it with deactivate_locked_super() (and repeat the search).

Longer term we want to set that flag in ->get_sb() instances (and
check for it to distinguish between "sget() found us a live sb"
and "sget() has allocated an sb, we need to set it up" in there,
instead of checking ->s_root as we do now).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org

The mbcache code was written to support a variable number of indexes,
but all the existing users use exactly one index.  Simplify to code to
support only that case.

There are also no users of the cache entry free operation, and none of
the users keep extra data in cache entries.  Remove those features as
well.
Signed-off-by: NAndreas Gruenbacher <agruen@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add a flags field to help glibc implementing statvfs(3) efficiently.

We copy the flag values from glibc, and add a new ST_VALID flag to
denote that f_flags is implemented.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We'll need the path to implement the flags field for statvfs support.
We do have it available in all callers except:

 - ecryptfs_statfs.  This one doesn't actually need vfs_statfs but just
   needs to do a caller to the lower filesystem statfs method.
 - sys_ustat.  Add a non-exported statfs_by_dentry helper for it which
   doesn't won't be able to fill out the flags field later on.

In addition rename the helpers for statfs vs fstatfs to do_*statfs instead
of the misleading vfs prefix.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and let iput_final() do the actual eviction or retention
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>