Although ww_mutexes degenerate into mutexes, it would be useful to
torture the deadlock handling between multiple ww_mutexes in addition to
torturing the regular mutexes.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-3-chris@chris-wilson.co.ukSigned-off-by: NIngo Molnar <mingo@kernel.org>

From conflicting macro parameters, passing the wrong name to
__MUTEX_INITIALIZER and a stray '\', #define __WW_MUTEX_INITIALIZER was
very unhappy.

One unnecessary change was to choose to pass &ww_class instead of
implicitly taking the address of the class within the macro.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 1b375dc3 ("mutex: Move ww_mutex definitions to ww_mutex.h")
Link: http://lkml.kernel.org/r/20161201114711.28697-2-chris@chris-wilson.co.ukSigned-off-by: NIngo Molnar <mingo@kernel.org>

Document the invariants we maintain for the wait list of ww_mutexes.
Signed-off-by: NNicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-13-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Help catch cases where mutex_lock is used directly on w/w mutexes, which
otherwise result in the w/w tasks reading uninitialized data.
Signed-off-by: NNicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-12-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Lock stealing is less beneficial for w/w mutexes since we may just end up
backing off if we stole from a thread with an earlier acquire stamp that
already holds another w/w mutex that we also need. So don't spin
optimistically unless we are sure that there is no other waiter that might
cause us to back off.

Median timings taken of a contention-heavy GPU workload:

Before:

  real    0m52.946s
  user    0m7.272s
  sys     1m55.964s

After:

  real    0m53.086s
  user    0m7.360s
  sys     1m46.204s

This particular workload still spends 20%-25% of CPU in mutex_spin_on_owner
according to perf, but my attempts to further reduce this spinning based on
various heuristics all lead to an increase in measured wall time despite
the decrease in sys time.
Signed-off-by: NNicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-11-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

In the following scenario, thread #1 should back off its attempt to lock
ww1 and unlock ww2 (assuming the acquire context stamps are ordered
accordingly).

    Thread #0               Thread #1
    ---------               ---------
                            successfully lock ww2
    set ww1->base.owner
                            attempt to lock ww1
                            confirm ww1->ctx == NULL
                            enter mutex_spin_on_owner
    set ww1->ctx

What was likely to happen previously is:

    attempt to lock ww2
    refuse to spin because
      ww2->ctx != NULL
    schedule()
                            detect thread #0 is off CPU
                            stop optimistic spin
                            return -EDEADLK
                            unlock ww2
                            wakeup thread #0
    lock ww2

Now, we are more likely to see:

                            detect ww1->ctx != NULL
                            stop optimistic spin
                            return -EDEADLK
                            unlock ww2
    successfully lock ww2

... because thread #1 will stop its optimistic spin as soon as possible.

The whole scenario is quite unlikely, since it requires thread #1 to get
between thread #0 setting the owner and setting the ctx. But since we're
idling here anyway, the additional check is basically free.

Found by inspection.
Signed-off-by: NNicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-10-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Instead of inlining __mutex_lock_common() 5 times, once for each
{state,ww} variant. Reduce this to two, ww and !ww.

Then add __always_inline to mutex_optimistic_spin(), so that that will
get inlined all 4 remaining times, for all {waiter,ww} variants.

   text    data     bss     dec     hex filename

   6301       0       0    6301    189d defconfig-build/kernel/locking/mutex.o
   4053       0       0    4053     fd5 defconfig-build/kernel/locking/mutex.o
   4257       0       0    4257    10a1 defconfig-build/kernel/locking/mutex.o

This reduces total text size and better separates the ww and !ww mutex
code generation.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

locking/ww_mutex: Optimize ww-mutexes by waking at most one waiter for backoff when acquiring the lock

The wait list is sorted by stamp order, and the only waiting task that may
have to back off is the first waiter with a context.

The regular slow path does not have to wake any other tasks at all, since
all other waiters that would have to back off were either woken up when
the waiter was added to the list, or detected the condition before they
added themselves.

Median timings taken of a contention-heavy GPU workload:

Without this series:

  real    0m59.900s
  user    0m7.516s
  sys     2m16.076s

With changes up to and including this patch:

  real    0m52.946s
  user    0m7.272s
  sys     1m55.964s
Signed-off-by: NNicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-9-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

While adding our task as a waiter, detect if another task should back off
because of us.

With this patch, we establish the invariant that the wait list contains
at most one (sleeping) waiter with ww_ctx->acquired > 0, and this waiter
will be the first waiter with a context.

Since only waiters with ww_ctx->acquired > 0 have to back off, this allows
us to be much more economical with wakeups.
Signed-off-by: NNicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-8-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add regular waiters in stamp order. Keep adding waiters that have no
context in FIFO order and take care not to starve them.

While adding our task as a waiter, back off if we detect that there is
a waiter with a lower stamp in front of us.

Make sure to call lock_contended even when we back off early.

For w/w mutexes, being first in the wait list is only stable when
taking the lock without a context. Therefore, the purpose of the first
flag is split into two: 'first' remains to indicate whether we want to
spin optimistically, while 'handoff' indicates that we should be
prepared to accept a handoff.

For w/w locking with a context, we always accept handoffs after the
first schedule(), to handle the following sequence of events:

 1. Task #0 unlocks and hands off to Task #2 which is first in line

 2. Task #1 adds itself in front of Task #2

 3. Task #2 wakes up and must accept the handoff even though it is no
    longer first in line
Signed-off-by: NNicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: =?UTF-8?q?Nicolai=20H=C3=A4hnle?= <Nicolai.Haehnle@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-7-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Keep the documentation in the header file since there is no good place
for it in mutex.c: there are two rather different implementations with
different EXPORT_SYMBOLs for each function.
Signed-off-by: NNicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: =?UTF-8?q?Nicolai=20H=C3=A4hnle?= <Nicolai.Haehnle@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-6-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

We will add a new field to struct mutex_waiter.  This field must be
initialized for all waiters if any waiter uses the ww_use_ctx path.

So there is a trade-off: Keep ww_mutex locking without a context on
the faster non-use_ww_ctx path, at the cost of adding the
initialization to all mutex locks (including non-ww_mutexes), or avoid
the additional cost for non-ww_mutex locks, at the cost of adding
additional checks to the use_ww_ctx path.

We take the latter choice.  It may be worth eliminating the users of
ww_mutex_lock(lock, NULL), but there are a lot of them.
Signed-off-by: NNicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-5-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The function will be re-used in subsequent patches.
Signed-off-by: NNicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-4-git-send-email-nhaehnle@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

While reviewing the ww_mutex patches, I noticed that it was still
possible to (incorrectly) succeed for (incorrect) code like:

	mutex_lock(&a);
	mutex_lock(&a);

This was possible if the second mutex_lock() would block (as expected)
but then receive a spurious wakeup. At that point it would find itself
at the front of the queue, request a handoff and instantly claim
ownership and continue, since owner would point to itself.

Avoid this scenario and simplify the code by introducing a third low
bit to signal handoff pickup. So once we request handoff, unlock
clears the handoff bit and sets the pickup bit along with the new
owner.

This also removes the need for the .handoff argument to
__mutex_trylock(), since that becomes superfluous with PICKUP.

In order to guarantee enough low bits, ensure task_struct alignment is
at least L1_CACHE_BYTES (which seems a good ideal regardless).
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 9d659ae1 ("locking/mutex: Add lock handoff to avoid starvation")
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The use of any kind of wait queue is an overkill for pcpu-rwsems.
While one option would be to use the less heavy simple (swait)
flavor, this is still too much for what pcpu-rwsems needs. For one,
we do not care about any sort of queuing in that the only (rare) time
writers (and readers, for that matter) are queued is when trying to
acquire the regular contended rw_sem. There cannot be any further
queuing as writers are serialized by the rw_sem in the first place.

Given that percpu_down_write() must not be called after exit_notify(),
we can replace the bulky waitqueue with rcuwait such that a writer
can wait for its turn to take the lock. As such, we can avoid the
queue handling and locking overhead.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1484148146-14210-3-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

rcuwait provides support for (single) RCU-safe task wait/wake functionality,
with the caveat that it must not be called after exit_notify(), such that
we avoid racing with rcu delayed_put_task_struct callbacks, task_struct
being rcu unaware in this context -- for which we similarly have
task_rcu_dereference() magic, but with different return semantics, which
can conflict with the wakeup side.

The interfaces are quite straightforward:

  rcuwait_wait_event()
  rcuwait_wake_up()

More details are in the comments, but it's perhaps worth mentioning at least,
that users must provide proper serialization when waiting on a condition, and
avoid corrupting a concurrent waiter. Also care must be taken between the task
and the condition for when calling the wakeup -- we cannot miss wakeups. When
porting users, this is for example, a given when using waitqueues in that
everything is done under the q->lock. As such, it can remove sources of non
preemptable unbounded work for realtime.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1484148146-14210-2-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

This is a nasty interface and setting the state of a foreign task must
not be done. As of the following commit:

  be628be0 ("bcache: Make gc wakeup sane, remove set_task_state()")

... everyone in the kernel calls set_task_state() with current, allowing
the helper to be removed.

However, as the comment indicates, it is still around for those archs
where computing current is more expensive than using a pointer, at least
in theory. An important arch that is affected is arm64, however this has
been addressed now [1] and performance is up to par making no difference
with either calls.

Of all the callers, if any, it's the locking bits that would care most
about this -- ie: we end up passing a tsk pointer to a lot of the lock
slowpath, and setting ->state on that. The following numbers are based
on two tests: a custom ad-hoc microbenchmark that just measures
latencies (for ~65 million calls) between get_task_state() vs
get_current_state().

Secondly for a higher overview, an unlink microbenchmark was used,
which pounds on a single file with open, close,unlink combos with
increasing thread counts (up to 4x ncpus). While the workload is quite
unrealistic, it does contend a lot on the inode mutex or now rwsem.

[1] https://lkml.kernel.org/r/1483468021-8237-1-git-send-email-mark.rutland@arm.com

== 1. x86-64 ==

Avg runtime set_task_state():    601 msecs
Avg runtime set_current_state(): 552 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      36089.26 (  0.00%)    38977.33 (  8.00%)
Hmean    unlink1-processes-5      28555.01 (  0.00%)    29832.55 (  4.28%)
Hmean    unlink1-processes-8      37323.75 (  0.00%)    44974.57 ( 20.50%)
Hmean    unlink1-processes-12     43571.88 (  0.00%)    44283.01 (  1.63%)
Hmean    unlink1-processes-21     34431.52 (  0.00%)    38284.45 ( 11.19%)
Hmean    unlink1-processes-30     34813.26 (  0.00%)    37975.17 (  9.08%)
Hmean    unlink1-processes-48     37048.90 (  0.00%)    39862.78 (  7.59%)
Hmean    unlink1-processes-79     35630.01 (  0.00%)    36855.30 (  3.44%)
Hmean    unlink1-processes-110    36115.85 (  0.00%)    39843.91 ( 10.32%)
Hmean    unlink1-processes-141    32546.96 (  0.00%)    35418.52 (  8.82%)
Hmean    unlink1-processes-172    34674.79 (  0.00%)    36899.21 (  6.42%)
Hmean    unlink1-processes-203    37303.11 (  0.00%)    36393.04 ( -2.44%)
Hmean    unlink1-processes-224    35712.13 (  0.00%)    36685.96 (  2.73%)

== 2. ppc64le ==

Avg runtime set_task_state():  938 msecs
Avg runtime set_current_state: 940 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      19269.19 (  0.00%)    30704.50 ( 59.35%)
Hmean    unlink1-processes-5      20106.15 (  0.00%)    21804.15 (  8.45%)
Hmean    unlink1-processes-8      17496.97 (  0.00%)    17243.28 ( -1.45%)
Hmean    unlink1-processes-12     14224.15 (  0.00%)    17240.21 ( 21.20%)
Hmean    unlink1-processes-21     14155.66 (  0.00%)    15681.23 ( 10.78%)
Hmean    unlink1-processes-30     14450.70 (  0.00%)    15995.83 ( 10.69%)
Hmean    unlink1-processes-48     16945.57 (  0.00%)    16370.42 ( -3.39%)
Hmean    unlink1-processes-79     15788.39 (  0.00%)    14639.27 ( -7.28%)
Hmean    unlink1-processes-110    14268.48 (  0.00%)    14377.40 (  0.76%)
Hmean    unlink1-processes-141    14023.65 (  0.00%)    16271.69 ( 16.03%)
Hmean    unlink1-processes-172    13417.62 (  0.00%)    16067.55 ( 19.75%)
Hmean    unlink1-processes-203    15293.08 (  0.00%)    15440.40 (  0.96%)
Hmean    unlink1-processes-234    13719.32 (  0.00%)    16190.74 ( 18.01%)
Hmean    unlink1-processes-265    16400.97 (  0.00%)    16115.22 ( -1.74%)
Hmean    unlink1-processes-296    14388.60 (  0.00%)    16216.13 ( 12.70%)
Hmean    unlink1-processes-320    15771.85 (  0.00%)    15905.96 (  0.85%)

x86-64 (known to be fast for get_current()/this_cpu_read_stable() caching)
and ppc64 (with paca) show similar improvements in the unlink microbenches.
The small delta for ppc64 (2ms), does not represent the gains on the unlink
runs. In the case of x86, there was a decent amount of variation in the
latency runs, but always within a 20 to 50ms increase), ppc was more constant.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1483479794-14013-5-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch effectively replaces the tsk pointer dereference
(which is obviously == current), to directly use get_current()
macro. This is to make the removal of setting foreign task
states smoother and painfully obvious. Performance win on some
archs such as x86-64 and ppc64. On a microbenchmark that calls
set_task_state() vs set_current_state() and an inode rwsem
pounding benchmark doing unlink:

== 1. x86-64 ==

Avg runtime set_task_state():    601 msecs
Avg runtime set_current_state(): 552 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      36089.26 (  0.00%)    38977.33 (  8.00%)
Hmean    unlink1-processes-5      28555.01 (  0.00%)    29832.55 (  4.28%)
Hmean    unlink1-processes-8      37323.75 (  0.00%)    44974.57 ( 20.50%)
Hmean    unlink1-processes-12     43571.88 (  0.00%)    44283.01 (  1.63%)
Hmean    unlink1-processes-21     34431.52 (  0.00%)    38284.45 ( 11.19%)
Hmean    unlink1-processes-30     34813.26 (  0.00%)    37975.17 (  9.08%)
Hmean    unlink1-processes-48     37048.90 (  0.00%)    39862.78 (  7.59%)
Hmean    unlink1-processes-79     35630.01 (  0.00%)    36855.30 (  3.44%)
Hmean    unlink1-processes-110    36115.85 (  0.00%)    39843.91 ( 10.32%)
Hmean    unlink1-processes-141    32546.96 (  0.00%)    35418.52 (  8.82%)
Hmean    unlink1-processes-172    34674.79 (  0.00%)    36899.21 (  6.42%)
Hmean    unlink1-processes-203    37303.11 (  0.00%)    36393.04 ( -2.44%)
Hmean    unlink1-processes-224    35712.13 (  0.00%)    36685.96 (  2.73%)

== 2. ppc64le ==

Avg runtime set_task_state():  938 msecs
Avg runtime set_current_state: 940 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      19269.19 (  0.00%)    30704.50 ( 59.35%)
Hmean    unlink1-processes-5      20106.15 (  0.00%)    21804.15 (  8.45%)
Hmean    unlink1-processes-8      17496.97 (  0.00%)    17243.28 ( -1.45%)
Hmean    unlink1-processes-12     14224.15 (  0.00%)    17240.21 ( 21.20%)
Hmean    unlink1-processes-21     14155.66 (  0.00%)    15681.23 ( 10.78%)
Hmean    unlink1-processes-30     14450.70 (  0.00%)    15995.83 ( 10.69%)
Hmean    unlink1-processes-48     16945.57 (  0.00%)    16370.42 ( -3.39%)
Hmean    unlink1-processes-79     15788.39 (  0.00%)    14639.27 ( -7.28%)
Hmean    unlink1-processes-110    14268.48 (  0.00%)    14377.40 (  0.76%)
Hmean    unlink1-processes-141    14023.65 (  0.00%)    16271.69 ( 16.03%)
Hmean    unlink1-processes-172    13417.62 (  0.00%)    16067.55 ( 19.75%)
Hmean    unlink1-processes-203    15293.08 (  0.00%)    15440.40 (  0.96%)
Hmean    unlink1-processes-234    13719.32 (  0.00%)    16190.74 ( 18.01%)
Hmean    unlink1-processes-265    16400.97 (  0.00%)    16115.22 ( -1.74%)
Hmean    unlink1-processes-296    14388.60 (  0.00%)    16216.13 ( 12.70%)
Hmean    unlink1-processes-320    15771.85 (  0.00%)    15905.96 (  0.85%)
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1483479794-14013-4-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch effectively replaces the tsk pointer dereference
(which is obviously == current), to directly use get_current()
macro. This is to make the removal of setting foreign task
states smoother and painfully obvious. Performance win on some
archs such as x86-64 and ppc64 -- arm64 is no longer an issue.
Signed-off-by: NDavidlohr Bueso <dave@stgolabs.net>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1483479794-14013-3-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch effectively replaces the tsk pointer dereference (which is
obviously == current), to directly use get_current() macro. In this
case, do_exit() always passes current to exit_mm(), hence we can
simply get rid of the argument. This is also a performance win on some
archs such as x86-64 and ppc64 -- arm64 is no longer an issue.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1483479794-14013-2-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

This is a follow-up of commit:

  cfd8983f ("x86, locking/spinlocks: Remove ticket (spin)lock implementation")

The static_key structure 'paravirt_ticketlocks_enabled' is now removed as it is
no longer used.

As a result, the init functions kvm_spinlock_init_jump() and
xen_init_spinlocks_jump() are also removed.

A simple build and boot test was done to verify it.
Signed-off-by: NWaiman Long <longman@redhat.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1484252878-1962-1-git-send-email-longman@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

First of all, %*ph specifier allows to dump data in hex format using the
pointer to a buffer. This is suitable to use here.

Besides that Thomas suggested to move it to critical level and replace __FILE__
by explicit mention of "jumplabel".
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170110164354.47372-1-andriy.shevchenko@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

If prev node is not in running state or its vCPU is preempted, we can give
up our vCPU slices in pv_wait_node() ASAP.
Signed-off-by: NPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: longman@redhat.com
Link: http://lkml.kernel.org/r/1484035006-6787-1-git-send-email-xinhui.pan@linux.vnet.ibm.com
[ Fixed typos in the changelog, removed ugly linebreak from the code. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The spin_lock_bh_nested() API is defined but is not used anywhere
in the kernel. So all spin_lock_bh_nested() and related APIs are
now removed.
Signed-off-by: NWaiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1483975612-16447-1-git-send-email-longman@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Merge fixes from Andrew Morton:
 "27 fixes.

  There are three patches that aren't actually fixes. They're simple
  function renamings which are nice-to-have in mainline as ongoing net
  development depends on them."

* akpm: (27 commits)
  timerfd: export defines to userspace
  mm/hugetlb.c: fix reservation race when freeing surplus pages
  mm/slab.c: fix SLAB freelist randomization duplicate entries
  zram: support BDI_CAP_STABLE_WRITES
  zram: revalidate disk under init_lock
  mm: support anonymous stable page
  mm: add documentation for page fragment APIs
  mm: rename __page_frag functions to __page_frag_cache, drop order from drain
  mm: rename __alloc_page_frag to page_frag_alloc and __free_page_frag to page_frag_free
  mm, memcg: fix the active list aging for lowmem requests when memcg is enabled
  mm: don't dereference struct page fields of invalid pages
  mailmap: add codeaurora.org names for nameless email commits
  signal: protect SIGNAL_UNKILLABLE from unintentional clearing.
  mm: pmd dirty emulation in page fault handler
  ipc/sem.c: fix incorrect sem_lock pairing
  lib/Kconfig.debug: fix frv build failure
  mm: get rid of __GFP_OTHER_NODE
  mm: fix remote numa hits statistics
  mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}
  ocfs2: fix crash caused by stale lvb with fsdlm plugin
  ...

Pull networking fixes from David Miller:

 1) Fix rtlwifi crash, from Larry Finger.

 2) Memory disclosure in appletalk ipddp routing code, from Vlad
    Tsyrklevich.

 3) r8152 can erroneously split an RX packet into multiple URBs if the
    Rx FIFO is not empty when we suspend. Fix this by waiting for the
    FIFO to empty before suspending. From Hayes Wang.

 4) Two GRO fixes (enter slow path when not enough SKB tail room exists,
    disable frag0 optimizations when there are IPV6 extension headers)
    from Eric Dumazet and Herbert Xu.

 5) A series of mlx5e bug fixes (do source udp port offloading for
    tunnels properly, Ip fragment matching fixes, handling firmware
    errors properly when installing TC rules, etc.) from Saeed Mahameed,
    Or Gerlitz, Roi Dayan, Hadar Hen Zion, Gil Rockah, and Daniel
    Jurgens.

 6) Two VRF fixes from David Ahern (don't skip multipath selection for
    VRF paths, disallow VRF to be configured with table ID 0).

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (35 commits)
  net: vrf: do not allow table id 0
  net: phy: marvell: fix Marvell 88E1512 used in SGMII mode
  sctp: Fix spelling mistake: "Atempt" -> "Attempt"
  net: ipv4: Fix multipath selection with vrf
  cgroup: move CONFIG_SOCK_CGROUP_DATA to init/Kconfig
  gro: use min_t() in skb_gro_reset_offset()
  net/mlx5: Only cancel recovery work when cleaning up device
  net/mlx5e: Remove WARN_ONCE from adaptive moderation code
  net/mlx5e: Un-register uplink representor on nic_disable
  net/mlx5e: Properly handle FW errors while adding TC rules
  net/mlx5e: Fix kbuild warnings for uninitialized parameters
  net/mlx5e: Set inline mode requirements for matching on IP fragments
  net/mlx5e: Properly get address type of encapsulation IP headers
  net/mlx5e: TC ipv4 tunnel encap offload error flow fixes
  net/mlx5e: Warn when rejecting offload attempts of IP tunnels
  net/mlx5e: Properly handle offloading of source udp port for IP tunnels
  gro: Disable frag0 optimization on IPv6 ext headers
  gro: Enter slow-path if there is no tailroom
  mlx4: Return EOPNOTSUPP instead of ENOTSUPP
  net/af_iucv: don't use paged skbs for TX on HiperSockets
  ...

Pull crypto fix from Herbert Xu:
 "This fixes a regression in aesni that renders it useless if it's
  built-in with a modular pcbc configuration"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: aesni - Fix failure when built-in with modular pcbc

Frank reported that vrf devices can be created with a table id of 0.
This breaks many of the run time table id checks and should not be
allowed. Detect this condition at create time and fail with EINVAL.

Fixes: 193125db ("net: Introduce VRF device driver")
Reported-by: NFrank Kellermann <frank.kellermann@atos.net>
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When an Marvell 88E1512 PHY is connected to a nic in SGMII mode, the
fiber page is used for the SGMII host-side connection.  The PHY driver
notices that SUPPORTED_FIBRE is set, so it tries reading the fiber page
for the link status, and ends up reading the MAC-side status instead of
the outgoing (copper) link.  This leads to incorrect results reported
via ethtool.

If the PHY is connected via SGMII to the host, ignore the fiber page.
However, continue to allow the existing power management code to
suspend and resume the fiber page.

Fixes: 6cfb3bcc ("Marvell phy: check link status in case of fiber link.")
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Trivial fix to spelling mistake in WARN_ONCE message
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib_select_path does not call fib_select_multipath if oif is set in the
flow struct. For VRF use cases oif is always set, so multipath route
selection is bypassed. Use the FLOWI_FLAG_SKIP_NH_OIF to skip the oif
check similar to what is done in fib_table_lookup.

Add saddr and proto to the flow struct for the fib lookup done by the
VRF driver to better match hash computation for a flow.

Fixes: 613d09b3 ("net: Use VRF device index for lookups on TX")
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We now 'select SOCK_CGROUP_DATA' but Kconfig complains that this is
not right when CONFIG_NET is disabled and there is no socket interface:

warning: (CGROUP_BPF) selects SOCK_CGROUP_DATA which has unmet direct dependencies (NET)

I don't know what the correct solution for this is, but simply removing
the dependency on NET from SOCK_CGROUP_DATA by moving it out of the
'if NET' section avoids the warning and does not produce other build
errors.

Fixes: 483c4933 ("cgroup: Fix CGROUP_BPF config")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On 32bit arches, (skb->end - skb->data) is not 'unsigned int',
so we shall use min_t() instead of min() to avoid a compiler error.

Fixes: 1272ce87 ("gro: Enter slow-path if there is no tailroom")
Reported-by: Nkernel test robot <fengguang.wu@intel.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Saeed Mahameed says:

====================
Mellanox mlx5 fixes and cleanups 2017-01-10

This series includes some mlx5e general cleanups from Daniel, Gil, Hadar
and myself.
Also it includes some critical mlx5e TC offloads fixes from Or Gerlitz.

For -stable:
 - net/mlx5e: Remove WARN_ONCE from adaptive moderation code

   Although this fix doesn't affect any functionality, I thought it is
   better to clean this -WARN_ONCE- up for -stable in case someone hits
   such corner case.

Please apply and let me know if there's any problem.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Do not attempt to drain the health workqueue when unloading the device in
the recovery flow, this can cause a deadlock when the recovery work
tries to cancel itself with sync.

Because the work is no longer unconditionally canceled when unloading, it
must be explicitly canceled in the AER flow.

fixes: 689a248d ("net/mlx5: Cancel recovery work in remove flow")
Signed-off-by: NDaniel Jurgens <danielj@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When trying to do interface down or changing interface configuration
under heavy traffic, some of the adaptive moderation corner cases can
occur and leave a WARN_ONCE call trace in the kernel log.

Those WARN_ONCE are meant for debug only, and should have been inserted
only under debug. We avoid such call traces by removing those WARN_ONCE.

Fixes: cb3c7fd4 ("net/mlx5e: Support adaptive RX coalescing")
Signed-off-by: NGil Rockah <gilr@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The code before this patch registered uplink e-Switch representor
on nic_enable and unregistered on nic_cleanup, the right place
for this unregister is in nic_disable.

Fixes: 127ea380 ("net/mlx5: Add Representors registration API")
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Reviewed-by: NMohamad Haj Yahia <mohamad@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the firmware returns an error (common example is an attempt to
add twice the same rule which is refused by the some FWs), we are not
properly derefing/cleaning few resources allocated on the way.
Examples are vport vlan deref under eswitch vlan offloads, and encap
entry/neighbour deref under eswitch encapsulation offloads, fix that.

Fixes: a54e20b4 ('net/mlx5e: Add basic TC tunnel set action for SRIOV offloads')
Fixes: 8b32580d ('net/mlx5e: Add TC vlan action for SRIOV offloads')
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

kbuild warn about parameters that may be used uninitialized, fix it.

Fixes: a54e20b4 ('net/mlx5e: Add basic TC tunnel set action for SRIOV offloads')
Signed-off-by: NHadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For e-switch level matching on packets being an IP fragment, we
need to make sure the source vport inline mode is L3, fix that.

Fixes: 3f7d0eb4 ('net/mlx5e: Offload TC matching on packets being IP fragments')
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>