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  1. 25 Jan, 2019 12 commits
    • Paul E. McKenney's avatar
      rcu: Discard separate per-CPU callback counts · 260e1e4f
      Paul E. McKenney authored 
      Back when there were multiple flavors of RCU, it was necessary to
separately count lazy and non-lazy callbacks for each CPU.  These counts
were used in CONFIG_RCU_FAST_NO_HZ kernels to determine how long a newly
idle CPU should be allowed to sleep before handling its RCU callbacks.
But now that there is only one flavor, the callback counts for a given
CPU's sole rcu_data structure are the counts for that CPU.

This commit therefore removes the rcu_data structure's ->nonlazy_posted
and ->nonlazy_posted_snap fields, the rcu_idle_count_callbacks_posted()
and rcu_cpu_has_callbacks() functions, repurposes the rcu_data structure's
->all_lazy field to record the laziness state at the beginning of the
latest idle sojourn, and modifies CONFIG_RCU_FAST_NO_HZ RCU CPU stall
warnings accordingly.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      260e1e4f
    • Paul E. McKenney's avatar
      rcu: Inline _synchronize_rcu_expedited() into synchronize_rcu_expedited() · 89230726
      Paul E. McKenney authored 
      Now that _synchronize_rcu_expedited() has only one caller, and given that
this is a tail call, this commit inlines _synchronize_rcu_expedited()
into synchronize_rcu_expedited().
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      89230726
    • Paul E. McKenney's avatar
      rcu: Consolidate PREEMPT and !PREEMPT synchronize_rcu() · e5bc3af7
      Paul E. McKenney authored 
      Now that rcu_blocking_is_gp() makes the correct immediate-return
decision for both PREEMPT and !PREEMPT, a single implementation of
synchronize_rcu() will work correctly under both configurations.
This commit therefore eliminates a few lines of code by consolidating
the two implementations of synchronize_rcu().
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      e5bc3af7
    • Paul E. McKenney's avatar
      rcu: Consolidate PREEMPT and !PREEMPT synchronize_rcu_expedited() · 3cd4ca47
      Paul E. McKenney authored 
      The CONFIG_PREEMPT=n and CONFIG_PREEMPT=y implementations of
synchronize_rcu_expedited() are quite similar, and with small
modifications to rcu_blocking_is_gp() can be made identical.  This commit
therefore makes this change in order to save a few lines of code and to
reduce the amount of duplicate code.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      3cd4ca47
    • Paul E. McKenney's avatar
      rcu: Determine expedited-GP IPI handler at build time · 142d106d
      Paul E. McKenney authored 
      Back when there could be multiple RCU flavors running in the same kernel
at the same time, it was necessary to specify the expedited grace-period
IPI handler at runtime.  Now that there is only one RCU flavor, the
IPI handler can be determined at build time.  There is therefore no
longer any reason for the RCU-preempt and RCU-sched IPI handlers to
have different names, nor is there any reason to pass these handlers in
function arguments and in the data structures enclosing workqueues.

This commit therefore makes all these changes, pushing the specification
of the expedited grace-period IPI handler down to the point of use.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      142d106d
    • Paul E. McKenney's avatar
      rcu: Inline rcu_kthread_do_work() into its sole remaining caller · c46f497a
      Paul E. McKenney authored 
      The rcu_kthread_do_work() function has a single-line body and only one
remaining caller.  This commit therefore saves a few lines of code by
inlining rcu_kthread_do_work() into its sole remaining caller.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      c46f497a
    • Paul E. McKenney's avatar
      rcu: Eliminate RCU_BH_FLAVOR and RCU_SCHED_FLAVOR · c97058d0
      Paul E. McKenney authored 
      Now that the RCU flavors have been consolidated, RCU_BH_FLAVOR and
RCU_SCHED_FLAVOR are no longer used.  This commit therefore saves a
few lines by removing them.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      c97058d0
    • Paul E. McKenney's avatar
      rcu: Inline force_quiescent_state() into rcu_force_quiescent_state() · cd920e5a
      Paul E. McKenney authored 
      Given that rcu_force_quiescent_state() is a simple wrapper around
force_quiescent_state(), this commit saves a few lines of code by
inlining force_quiescent_state() into rcu_force_quiescent_state(),
and changing all references to force_quiescent_state() to instead
invoke rcu_force_quiescent_state().
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      cd920e5a
    • Paul E. McKenney's avatar
      rcu: Make expedited IPI handler return after handling critical section · 1de462ed
      Paul E. McKenney authored 
      During expedited RCU grace-period initialization, IPIs are sent to
all non-idle online CPUs.  The IPI handler checks to see if the CPU is
in quiescent state, reporting one if so.  This handler looks at three
different cases: (1) The CPU is not in an rcu_read_lock()-based critical
section, (2) The CPU is in the process of exiting an rcu_read_lock()-based
critical section, and (3) The CPU is in an rcu_read_lock()-based critical
section.  In case (2), execution falls through into case (3).

This is harmless from a functionality viewpoint, but can result in
needless overhead during an improbable corner case.  This commit therefore
adds the "return" statement needed to prevent fall-through.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      1de462ed
    • Paul E. McKenney's avatar
      rcu: Rename and comment changes due to only one rcuo kthread per CPU · ad368d15
      Paul E. McKenney authored 
      Given RCU flavor consolidation, the name rcu_spawn_all_nocb_kthreads()
is quite misleading.  It no longer ever creates more than one kthread,
and it does so only for the specified CPU.  This commit therefore changes
this name to the more descriptive rcu_spawn_cpu_nocb_kthread(), and also
fixes up a similar issue in its header comment while in the area.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
      ad368d15
    • Paul E. McKenney's avatar
      sched: Replace synchronize_sched() with synchronize_rcu() · b290ebcf
      Paul E. McKenney authored 
      Now that synchronize_rcu() waits for preempt-disable regions of
code as well as RCU read-side critical sections, synchronize_sched()
can be replaced by synchronize_rcu(), in fact, synchronize_sched()
is now completely equivalent to synchronize_rcu().  This commit
therefore replaces synchronize_sched() with synchronize_rcu() so that
synchronize_sched() can eventually be removed entirely.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
      b290ebcf
    • Paul E. McKenney's avatar
      sched: Replace call_rcu_sched() with call_rcu() · 337e9b07
      Paul E. McKenney authored 
      Now that call_rcu()'s callback is not invoked until after all
preempt-disable regions of code have completed (in addition to explicitly
marked RCU read-side critical sections), call_rcu() can be used in place
of call_rcu_sched().  This commit therefore makes that change.

While in the area, this commit also updates an outdated header comment
for for_each_domain().
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
      337e9b07
  3. 21 Jan, 2019 3 commits
    • Paul E. McKenney's avatar
      tools/memory-model: Make scripts take "-j" abbreviation for "--jobs" · 910cc959
      Paul E. McKenney authored 
      The "--jobs" argument to the litmus-test scripts is similar to the "-jN"
argument to "make", so this commit allows the "-jN" form as well.  While
in the area, it also prohibits the various forms of "-j0".
Suggested-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/20181203230451.28921-3-paulmck@linux.ibm.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      910cc959
    • Paul E. McKenney's avatar
      tools/memory-model: Add scripts to check github litmus tests · b02eb5b0
      Paul E. McKenney authored 
      The https://github.com/paulmckrcu/litmus repository contains a large
number of C-language litmus tests that include "Result:" comments
predicting the verification result.  This commit adds a number of scripts
that run tests on these litmus tests:

checkghlitmus.sh:
	Runs all litmus tests in the https://github.com/paulmckrcu/litmus
        archive that are C-language and that have "Result:" comment lines
	documenting expected results, comparing the actual results to
	those expected.  Clones the repository if it has not already
	been cloned into the "tools/memory-model/litmus" directory.

initlitmushist.sh
	Run all litmus tests having no more than the specified number
	of processes given a specified timeout, recording the results in
	.litmus.out files.  Clones the repository if it has not already
	been cloned into the "tools/memory-model/litmus" directory.

newlitmushist.sh
	For all new or updated litmus tests having no more than the
	specified number of processes given a specified timeout, run
	and record the results in .litmus.out files.

checklitmushist.sh
	Run all litmus tests having .litmus.out files from previous
	initlitmushist.sh or newlitmushist.sh runs, comparing the
	herd output to that of the original runs.

The above scripts will run litmus tests concurrently, by default with
one job per available CPU.  Giving any of these scripts the --help
argument will cause them to print usage information.

This commit also adds a number of helper scripts that are not intended
to be invoked from the command line:

cmplitmushist.sh: Compare the output of two different runs of the same
	litmus test.

judgelitmus.sh: Compare the output of a litmus test to its "Result:"
	comment line.

parseargs.sh: Parse command-line arguments.

runlitmushist.sh: Run the litmus tests whose pathnames are provided one
	per line on standard input.

While in the area, this commit also makes the existing checklitmus.sh
and checkalllitmus.sh scripts use parseargs.sh in order to provide a
bit of uniformity.  In addition, per-litmus-test status output is directed
to stdout, while end-of-test summary information is directed to stderr.
Finally, the error flag standardizes on "!!!" to assist those familiar
with rcutorture output.

The defaults for the parseargs.sh arguments may be overridden by using
environment variables: LKMM_DESTDIR for --destdir, LKMM_HERD_OPTIONS
for --herdoptions, LKMM_JOBS for --jobs, LKMM_PROCS for --procs, and
LKMM_TIMEOUT for --timeout.

[ paulmck: History-check summary-line changes per Alan Stern feedback. ]
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: stern@rowland.harvard.edu
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/20181203230451.28921-2-paulmck@linux.ibm.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      b02eb5b0
    • Andrea Parri's avatar
      tools/memory-model: Model smp_mb__after_unlock_lock() · 5b735eb1
      Andrea Parri authored 
      The kernel documents smp_mb__after_unlock_lock() the following way:

  "Place this after a lock-acquisition primitive to guarantee that
   an UNLOCK+LOCK pair acts as a full barrier.  This guarantee applies
   if the UNLOCK and LOCK are executed by the same CPU or if the
   UNLOCK and LOCK operate on the same lock variable."

Formalize in LKMM the above guarantee by defining (new) mb-links according
to the law:

  ([M] ; po ; [UL] ; (co | po) ; [LKW] ;
	fencerel(After-unlock-lock) ; [M])

where the component ([UL] ; co ; [LKW]) identifies "UNLOCK+LOCK pairs on
the same lock variable" and the component ([UL] ; po ; [LKW]) identifies
"UNLOCK+LOCK pairs executed by the same CPU".

In particular, the LKMM forbids the following two behaviors (the second
litmus test below is based on:

  Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html

c.f., Section "Tree RCU Grace Period Memory Ordering Building Blocks"):

C after-unlock-lock-same-cpu

(*
 * Result: Never
 *)

{}

P0(spinlock_t *s, spinlock_t *t, int *x, int *y)
{
	int r0;

	spin_lock(s);
	WRITE_ONCE(*x, 1);
	spin_unlock(s);
	spin_lock(t);
	smp_mb__after_unlock_lock();
	r0 = READ_ONCE(*y);
	spin_unlock(t);
}

P1(int *x, int *y)
{
	int r0;

	WRITE_ONCE(*y, 1);
	smp_mb();
	r0 = READ_ONCE(*x);
}

exists (0:r0=0 /\ 1:r0=0)

C after-unlock-lock-same-lock-variable

(*
 * Result: Never
 *)

{}

P0(spinlock_t *s, int *x, int *y)
{
	int r0;

	spin_lock(s);
	WRITE_ONCE(*x, 1);
	r0 = READ_ONCE(*y);
	spin_unlock(s);
}

P1(spinlock_t *s, int *y, int *z)
{
	int r0;

	spin_lock(s);
	smp_mb__after_unlock_lock();
	WRITE_ONCE(*y, 1);
	r0 = READ_ONCE(*z);
	spin_unlock(s);
}

P2(int *z, int *x)
{
	int r0;

	WRITE_ONCE(*z, 1);
	smp_mb();
	r0 = READ_ONCE(*x);
}

exists (0:r0=0 /\ 1:r0=0 /\ 2:r0=0)
Signed-off-by: default avatarAndrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
Cc: Akira Yokosawa <akiyks@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Daniel Lustig <dlustig@nvidia.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luc Maranget <luc.maranget@inria.fr>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: parri.andrea@gmail.com
Link: http://lkml.kernel.org/r/20181203230451.28921-1-paulmck@linux.ibm.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      5b735eb1
  5. 18 Jan, 2019 4 commits
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma · d7393226
      Linus Torvalds authored 
      Pull rdma fixes frfom Jason Gunthorpe:
 "Not much so far. We have the usual batch of bugs and two fixes to code
  merged this cycle:

   - Restore valgrind support for the ioctl verbs interface merged this
     window, and fix a missed error code on an error path from that
     conversion

   - A user reported crash on obsolete mthca hardware

   - pvrdma was using the wrong command opcode toward the hypervisor

   - NULL pointer crash regression when dumping rdma-cm over netlink

   - Be conservative about exposing the global rkey"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/uverbs: Mark ioctl responses with UVERBS_ATTR_F_VALID_OUTPUT
  RDMA/mthca: Clear QP objects during their allocation
  RDMA/vmw_pvrdma: Return the correct opcode when creating WR
  RDMA/cma: Add cm_id restrack resource based on kernel or user cm_id type
  RDMA/nldev: Don't expose unsafe global rkey to regular user
  RDMA/uverbs: Fix post send success return value in case of error
      d7393226
    • Linus Torvalds's avatar
      Merge tag 'drm-fixes-2019-01-18' of git://anongit.freedesktop.org/drm/drm · 1092a94f
      Linus Torvalds authored 
      Pull drm fixes from Dave Airlie:
 "The rc3 fixes are a bit scattered:

   - meson, sun4i and rockchip all had missing of_node_put.

   - qxl and virtio both were advertising dma-buf to userspace when they
     really shouldn't have.

  Otherwise:

  meson:
   - modesetting regression fix

  i915 GVT:
   - one cmd parser failure fix
   - region cleanup fix in vGPU destroy

  amdgpu:
   - KFD fixes for arm64 mixed APU/DGPU
   - vega12 powerplay fix
   - raven DC fixes
   - freesync fix"

* tag 'drm-fixes-2019-01-18' of git://anongit.freedesktop.org/drm/drm:
  drm/amd/display: Detach backlight from stream
  drm/sun4i: backend: add missing of_node_puts
  Revert "drm/amdgpu: validate user pitch alignment"
  Revert "drm/amdgpu: validate user GEM object size"
  drm/meson: Fix atomic mode switching regression
  drm/i915/gvt: Fix mmap range check
  drm/i915/gvt: free VFIO region space in vgpu detach
  drm/amd/display: Fix disabled cursor on top screen edge
  drm/amd/display: fix warning on raven hotplug
  drm/amd/display: fix PME notification not working in RV desktop
  drm/amd/display: Only get the connector state for VRR when toggled
  drm/amd/display: Pack DMCU iRAM alignment
  drm/amd/powerplay: run acg btc for Vega12
  drm/amdkfd: Don't assign dGPUs to APU topology devices
  drm/amdkfd: Allow building KFD on ARM64 (v2)
  drm/meson: add missing of_node_put
  drm/virtio: drop prime import/export callbacks
  drm/qxl: drop prime import/export callbacks
  drm/i915/gvt: Allow F_CMD_ACCESS on mmio 0x21f0
  drm/rockchip: add missing of_node_put
      1092a94f
    • Linus Torvalds's avatar
      Merge tag 'led-fix-for-5.0-rc3' of... · 2451f371
      Linus Torvalds authored 
      Merge tag 'led-fix-for-5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds

Pull LED fix from Jacek Anaszewski.

* tag 'led-fix-for-5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
  leds: lp5523: fix a missing check of return value of lp55xx_read
      2451f371
    • Linus Torvalds's avatar
      Merge tag 'hwmon-for-v5.0-rc3' of... · 0a2fbed8
      Linus Torvalds authored 
      Merge tag 'hwmon-for-v5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:
 "Minor fixes/regressions"

* tag 'hwmon-for-v5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (tmp421) Correct the misspelling of the tmp442 compatible attribute in OF device ID table
  hwmon: (occ) Fix potential integer overflow
  hwmon: (lm80) Fix missing unlock on error in set_fan_div()
  hwmon: (nct6775) Enable IO mapping for NCT6797D and NCT6798D
  hwmon: (nct6775) Fix chip ID for NCT6798D
      0a2fbed8
  7. 17 Jan, 2019 18 commits
  9. 16 Jan, 2019 3 commits
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