Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

3717f613 · Linus Torvalds <[email protected]> · 2019-03-05 14:49:11 -08:00

Pull RCU updates from Ingo Molnar:
 "The main RCU related changes in this cycle were:

   - Additional cleanups after RCU flavor consolidation

   - Grace-period forward-progress cleanups and improvements

   - Documentation updates

   - Miscellaneous fixes

   - spin_is_locked() conversions to lockdep

   - SPDX changes to RCU source and header files

   - SRCU updates

   - Torture-test updates, including nolibc updates and moving nolibc to
     tools/include"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
  locking/locktorture: Convert to SPDX license identifier
  linux/torture: Convert to SPDX license identifier
  torture: Convert to SPDX license identifier
  linux/srcu: Convert to SPDX license identifier
  linux/rcutree: Convert to SPDX license identifier
  linux/rcutiny: Convert to SPDX license identifier
  linux/rcu_sync: Convert to SPDX license identifier
  linux/rcu_segcblist: Convert to SPDX license identifier
  linux/rcupdate: Convert to SPDX license identifier
  linux/rcu_node_tree: Convert to SPDX license identifier
  rcu/update: Convert to SPDX license identifier
  rcu/tree: Convert to SPDX license identifier
  rcu/tiny: Convert to SPDX license identifier
  rcu/sync: Convert to SPDX license identifier
  rcu/srcu: Convert to SPDX license identifier
  rcu/rcutorture: Convert to SPDX license identifier
  rcu/rcu_segcblist: Convert to SPDX license identifier
  rcu/rcuperf: Convert to SPDX license identifier
  rcu/rcu.h: Convert to SPDX license identifier
  RCU/torture.txt: Remove section MODULE PARAMETERS
  ...

Commit: 3717f613f48df0222311f974cf8a06c8a6c97bae
Parents: b1b988a6 · cae45e1c

Merge commit. Changes below are compared with the first parent: b1b988a6.

Changes

63 files changed · +1395 −1268

File	Status	Add	Del	Content
Documentation/RCU/Design/Expedited-Grace-Periods/ExpSchedFlow.svg	modified	+11	−7	View file
Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html	modified	+13	−13	View file
Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html	modified	+3	−3	View file
Documentation/RCU/Design/Memory-Ordering/TreeRCU-callback-invocation.svg	modified	+1	−1	View file
Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp.svg	modified	+4	−4	View file
Documentation/RCU/Design/Memory-Ordering/TreeRCU-qs.svg	modified	+3	−3	View file
Documentation/RCU/Design/Requirements/Requirements.html	modified	+13	−7	View file
Documentation/RCU/stallwarn.txt	modified	+8	−7	View file
Documentation/RCU/torture.txt	modified	+2	−167	View file
Documentation/RCU/whatisRCU.txt	modified	+2	−2	View file
Documentation/admin-guide/kernel-parameters.txt	modified	+19	−13	View file
MAINTAINERS	modified	+6	−0	View file
include/asm-generic/bug.h	modified	+0	−3	View file
include/linux/rcu_node_tree.h	modified	+2	−15	View file
include/linux/rcu_segcblist.h	modified	+2	−15	View file
include/linux/rcu_sync.h	modified	+1	−14	View file
include/linux/rcupdate.h	modified	+13	−78	View file
include/linux/rcutiny.h	modified	+2	−15	View file
include/linux/rcutree.h	modified	+3	−16	View file
include/linux/srcu.h	modified	+3	−15	View file
include/linux/srcutiny.h	modified	+2	−15	View file
include/linux/srcutree.h	modified	+4	−16	View file
include/linux/torture.h	modified	+4	−16	View file
kernel/locking/locktorture.c	modified	+4	−17	View file
kernel/rcu/rcu.h	modified	+3	−18	View file
kernel/rcu/rcu_segcblist.c	modified	+2	−15	View file
kernel/rcu/rcu_segcblist.h	modified	+2	−15	View file
kernel/rcu/rcuperf.c	modified	+10	−17	View file
kernel/rcu/rcutorture.c	modified	+35	−24	View file
kernel/rcu/srcutiny.c	modified	+2	−15	View file
kernel/rcu/srcutree.c	modified	+26	−46	View file
kernel/rcu/sync.c	modified	+1	−14	View file
kernel/rcu/tiny.c	modified	+3	−16	View file
kernel/rcu/tree.c	modified	+162	−105	View file
kernel/rcu/tree.h	modified	+14	−39	View file
kernel/rcu/tree_exp.h	modified	+71	−130	View file
kernel/rcu/tree_plugin.h	modified	+57	−181	View file
kernel/rcu/update.c	modified	+2	−15	View file
kernel/sched/cpufreq.c	modified	+2	−2	View file
kernel/sched/cpufreq_schedutil.c	modified	+1	−1	View file
kernel/sched/sched.h	modified	+1	−1	View file
kernel/sched/topology.c	modified	+2	−2	View file
kernel/time/timer.c	modified	+1	−1	View file
kernel/torture.c	modified	+8	−17	View file
tools/testing/selftests/rcutorture/bin/nolibc.h → tools/include/nolibc/nolibc.h	renamed	+92	−26	View file
tools/memory-model/.gitignore	added	+1	−0	View file
tools/memory-model/README	modified	+2	−0	View file
tools/memory-model/linux-kernel.bell	modified	+2	−1	View file
tools/memory-model/linux-kernel.cat	modified	+3	−1	View file
tools/memory-model/linux-kernel.def	modified	+1	−0	View file
tools/memory-model/scripts/README	added	+70	−0	View file
tools/memory-model/scripts/checkalllitmus.sh	modified	+23	−30	View file
tools/memory-model/scripts/checkghlitmus.sh	added	+65	−0	View file
tools/memory-model/scripts/checklitmus.sh	modified	+11	−63	View file
tools/memory-model/scripts/checklitmushist.sh	added	+60	−0	View file
tools/memory-model/scripts/cmplitmushist.sh	added	+87	−0	View file
tools/memory-model/scripts/initlitmushist.sh	added	+68	−0	View file
tools/memory-model/scripts/judgelitmus.sh	added	+78	−0	View file
tools/memory-model/scripts/newlitmushist.sh	added	+61	−0	View file
tools/memory-model/scripts/parseargs.sh	added	+136	−0	View file
tools/memory-model/scripts/runlitmushist.sh	added	+87	−0	View file
tools/testing/selftests/rcutorture/bin/mkinitrd.sh	modified	+17	−10	View file
virt/kvm/kvm_main.c	modified	+1	−1	View file

Only the first 600 diff lines are shown. Download the complete patch.

Documentation/RCU/Design/Expedited-Grace-Periods/ExpSchedFlow.svg

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diff --git a/Documentation/RCU/Design/Expedited-Grace-Periods/ExpSchedFlow.svg b/Documentation/RCU/Design/Expedited-Grace-Periods/ExpSchedFlow.svg
index e4233ac..6189ffc 100644
--- a/Documentation/RCU/Design/Expedited-Grace-Periods/ExpSchedFlow.svg
+++ b/Documentation/RCU/Design/Expedited-Grace-Periods/ExpSchedFlow.svg
@@ -328,13 +328,13 @@
      inkscape:window-height="1148"
      id="namedview90"
      showgrid="true"
-     inkscape:zoom="0.80021373"
-     inkscape:cx="462.49289"
-     inkscape:cy="473.6718"
+     inkscape:zoom="0.69092787"
+     inkscape:cx="476.34085"
+     inkscape:cy="712.80957"
      inkscape:window-x="770"
      inkscape:window-y="24"
      inkscape:window-maximized="0"
-     inkscape:current-layer="g4114-9-3-9"
+     inkscape:current-layer="g4"
      inkscape:snap-grids="false"
      fit-margin-top="5"
      fit-margin-right="5"
@@ -813,14 +813,18 @@
       <text
          sodipodi:linespacing="125%"
          id="text4110-5-7-6-2-4-0"
-         y="841.88086"
+         y="670.74316"
          x="1460.1007"
          style="font-size:267.24359131px;font-style:normal;font-weight:normal;text-align:center;line-height:125%;letter-spacing:0px;word-spacing:0px;text-anchor:middle;fill:#000000;fill-opacity:1;stroke:none;font-family:Sans"
          xml:space="preserve"><tspan
-           y="841.88086"
+           y="670.74316"
+           x="1460.1007"
+           sodipodi:role="line"
+           id="tspan4925-1-2-4-5">Request</tspan><tspan
+           y="1004.7976"
            x="1460.1007"
            sodipodi:role="line"
-           id="tspan4925-1-2-4-5">reched_cpu()</tspan></text>
+           id="tspan3100">context switch</tspan></text>
     </g>
   </g>
 </svg>

Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html

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diff --git a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
index 8e4f873..19e7a5f 100644
--- a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
+++ b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
@@ -72,10 +72,10 @@ will ignore it because idle and offline CPUs are already residing
 in quiescent states.
 Otherwise, the expedited grace period will use
 <tt>smp_call_function_single()</tt> to send the CPU an IPI, which
-is handled by <tt>sync_rcu_exp_handler()</tt>.
+is handled by <tt>rcu_exp_handler()</tt>.
 
 <p>
-However, because this is preemptible RCU, <tt>sync_rcu_exp_handler()</tt>
+However, because this is preemptible RCU, <tt>rcu_exp_handler()</tt>
 can check to see if the CPU is currently running in an RCU read-side
 critical section.
 If not, the handler can immediately report a quiescent state.
@@ -145,19 +145,18 @@ expedited grace period is shown in the following diagram:
 <p><img src="ExpSchedFlow.svg" alt="ExpSchedFlow.svg" width="55%">
 
 <p>
-As with RCU-preempt's <tt>synchronize_rcu_expedited()</tt>,
+As with RCU-preempt, RCU-sched's
 <tt>synchronize_sched_expedited()</tt> ignores offline and
 idle CPUs, again because they are in remotely detectable
 quiescent states.
-However, the <tt>synchronize_rcu_expedited()</tt> handler
-is <tt>sync_sched_exp_handler()</tt>, and because the
+However, because the
 <tt>rcu_read_lock_sched()</tt> and <tt>rcu_read_unlock_sched()</tt>
 leave no trace of their invocation, in general it is not possible to tell
 whether or not the current CPU is in an RCU read-side critical section.
-The best that <tt>sync_sched_exp_handler()</tt> can do is to check
+The best that RCU-sched's <tt>rcu_exp_handler()</tt> can do is to check
 for idle, on the off-chance that the CPU went idle while the IPI
 was in flight.
-If the CPU is idle, then <tt>sync_sched_exp_handler()</tt> reports
+If the CPU is idle, then <tt>rcu_exp_handler()</tt> reports
 the quiescent state.
 
 <p> Otherwise, the handler forces a future context switch by setting the
@@ -298,19 +297,18 @@ Instead, the task pushing the grace period forward will include the
 idle CPUs in the mask passed to <tt>rcu_report_exp_cpu_mult()</tt>.
 
 <p>
-For RCU-sched, there is an additional check for idle in the IPI
-handler, <tt>sync_sched_exp_handler()</tt>.
+For RCU-sched, there is an additional check:
 If the IPI has interrupted the idle loop, then
-<tt>sync_sched_exp_handler()</tt> invokes <tt>rcu_report_exp_rdp()</tt>
+<tt>rcu_exp_handler()</tt> invokes <tt>rcu_report_exp_rdp()</tt>
 to report the corresponding quiescent state.
 
 <p>
 For RCU-preempt, there is no specific check for idle in the
-IPI handler (<tt>sync_rcu_exp_handler()</tt>), but because
+IPI handler (<tt>rcu_exp_handler()</tt>), but because
 RCU read-side critical sections are not permitted within the
-idle loop, if <tt>sync_rcu_exp_handler()</tt> sees that the CPU is within
+idle loop, if <tt>rcu_exp_handler()</tt> sees that the CPU is within
 RCU read-side critical section, the CPU cannot possibly be idle.
-Otherwise, <tt>sync_rcu_exp_handler()</tt> invokes
+Otherwise, <tt>rcu_exp_handler()</tt> invokes
 <tt>rcu_report_exp_rdp()</tt> to report the corresponding quiescent
 state, regardless of whether or not that quiescent state was due to
 the CPU being idle.
@@ -625,6 +623,8 @@ checks, but only during the mid-boot dead zone.
 <p>
 With this refinement, synchronous grace periods can now be used from
 task context pretty much any time during the life of the kernel.
+That is, aside from some points in the suspend, hibernate, or shutdown
+code path.
 
 <h3><a name="Summary">
 Summary</a></h3>

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

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diff --git a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html
index e4d94fb..8d21af0 100644
--- a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html
+++ b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html
@@ -485,13 +485,13 @@ section that the grace period must wait on.
 noted by <tt>rcu_node_context_switch()</tt> on the left.
 On the other hand, if the CPU takes a scheduler-clock interrupt
 while executing in usermode, a quiescent state will be noted by
-<tt>rcu_check_callbacks()</tt> on the right.
+<tt>rcu_sched_clock_irq()</tt> on the right.
 Either way, the passage through a quiescent state will be noted
 in a per-CPU variable.
 
 <p>The next time an <tt>RCU_SOFTIRQ</tt> handler executes on
 this CPU (for example, after the next scheduler-clock
-interrupt), <tt>__rcu_process_callbacks()</tt> will invoke
+interrupt), <tt>rcu_core()</tt> will invoke
 <tt>rcu_check_quiescent_state()</tt>, which will notice the
 recorded quiescent state, and invoke
 <tt>rcu_report_qs_rdp()</tt>.
@@ -651,7 +651,7 @@ to end.
 These callbacks are identified by <tt>rcu_advance_cbs()</tt>,
 which is usually invoked by <tt>__note_gp_changes()</tt>.
 As shown in the diagram below, this invocation can be triggered by
-the scheduling-clock interrupt (<tt>rcu_check_callbacks()</tt> on
+the scheduling-clock interrupt (<tt>rcu_sched_clock_irq()</tt> on
 the left) or by idle entry (<tt>rcu_cleanup_after_idle()</tt> on
 the right, but only for kernels build with
 <tt>CONFIG_RCU_FAST_NO_HZ=y</tt>).

Documentation/RCU/Design/Memory-Ordering/TreeRCU-callback-invocation.svg

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diff --git a/Documentation/RCU/Design/Memory-Ordering/TreeRCU-callback-invocation.svg b/Documentation/RCU/Design/Memory-Ordering/TreeRCU-callback-invocation.svg
index 8324083..3fcf0c1 100644
--- a/Documentation/RCU/Design/Memory-Ordering/TreeRCU-callback-invocation.svg
+++ b/Documentation/RCU/Design/Memory-Ordering/TreeRCU-callback-invocation.svg
@@ -349,7 +349,7 @@
        font-weight="bold"
        font-size="192"
        id="text202-7-5"
-       style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcu_check_callbacks()</text>
+       style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcu_sched_clock_irq()</text>
     <rect
        x="7069.6187"
        y="5087.4678"

Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp.svg

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diff --git a/Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp.svg b/Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp.svg
index acd73c7..2bcd742 100644
--- a/Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp.svg
+++ b/Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp.svg
@@ -3902,7 +3902,7 @@
          font-style="normal"
          y="-4418.6582"
          x="3745.7725"
-         xml:space="preserve">rcu_check_callbacks()</text>
+         xml:space="preserve">rcu_sched_clock_irq()</text>
     </g>
     <g
        transform="translate(-850.30204,55463.106)"
@@ -3924,7 +3924,7 @@
          font-style="normal"
          y="-4418.6582"
          x="3745.7725"
-         xml:space="preserve">rcu_process_callbacks()</text>
+         xml:space="preserve">rcu_core()</text>
       <text
          style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier"
          id="text202-7-5-3-27-0"
@@ -3933,7 +3933,7 @@
          font-style="normal"
          y="-4165.7954"
          x="3745.7725"
-         xml:space="preserve">rcu_check_quiescent_state())</text>
+         xml:space="preserve">rcu_check_quiescent_state()</text>
       <text
          style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier"
          id="text202-7-5-3-27-0-9"
@@ -4968,7 +4968,7 @@
        font-weight="bold"
        font-size="192"
        id="text202-7-5-19"
-       style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcu_check_callbacks()</text>
+       style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcu_sched_clock_irq()</text>
     <rect
        x="5314.2671"
        y="82817.688"

Documentation/RCU/Design/Memory-Ordering/TreeRCU-qs.svg

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diff --git a/Documentation/RCU/Design/Memory-Ordering/TreeRCU-qs.svg b/Documentation/RCU/Design/Memory-Ordering/TreeRCU-qs.svg
index 149bec2..779c9ac 100644
--- a/Documentation/RCU/Design/Memory-Ordering/TreeRCU-qs.svg
+++ b/Documentation/RCU/Design/Memory-Ordering/TreeRCU-qs.svg
@@ -775,7 +775,7 @@
          font-style="normal"
          y="-4418.6582"
          x="3745.7725"
-         xml:space="preserve">rcu_check_callbacks()</text>
+         xml:space="preserve">rcu_sched_clock_irq()</text>
     </g>
     <g
        transform="translate(399.7744,828.86448)"
@@ -797,7 +797,7 @@
          font-style="normal"
          y="-4418.6582"
          x="3745.7725"
-         xml:space="preserve">rcu_process_callbacks()</text>
+         xml:space="preserve">rcu_core()</text>
       <text
          style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier"
          id="text202-7-5-3-27-0"
@@ -806,7 +806,7 @@
          font-style="normal"
          y="-4165.7954"
          x="3745.7725"
-         xml:space="preserve">rcu_check_quiescent_state())</text>
+         xml:space="preserve">rcu_check_quiescent_state()</text>
       <text
          style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier"
          id="text202-7-5-3-27-0-9"

Documentation/RCU/Design/Requirements/Requirements.html

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diff --git a/Documentation/RCU/Design/Requirements/Requirements.html b/Documentation/RCU/Design/Requirements/Requirements.html
index 9fca73e..5a9238a 100644
--- a/Documentation/RCU/Design/Requirements/Requirements.html
+++ b/Documentation/RCU/Design/Requirements/Requirements.html
@@ -3099,7 +3099,7 @@ If you block forever in one of a given domain's SRCU read-side critical
 sections, then that domain's grace periods will also be blocked forever.
 Of course, one good way to block forever is to deadlock, which can
 happen if any operation in a given domain's SRCU read-side critical
-section can block waiting, either directly or indirectly, for that domain's
+section can wait, either directly or indirectly, for that domain's
 grace period to elapse.
 For example, this results in a self-deadlock:
 
@@ -3139,12 +3139,18 @@ API, which, in combination with <tt>srcu_read_unlock()</tt>,
 guarantees a full memory barrier.
 
 <p>
-Also unlike other RCU flavors, SRCU's callbacks-wait function
-<tt>srcu_barrier()</tt> may be invoked from CPU-hotplug notifiers,
-though this is not necessarily a good idea.
-The reason that this is possible is that SRCU is insensitive
-to whether or not a CPU is online, which means that <tt>srcu_barrier()</tt>
-need not exclude CPU-hotplug operations.
+Also unlike other RCU flavors, <tt>synchronize_srcu()</tt> may <b>not</b>
+be invoked from CPU-hotplug notifiers, due to the fact that SRCU grace
+periods make use of timers and the possibility of timers being temporarily
+&ldquo;stranded&rdquo; on the outgoing CPU.
+This stranding of timers means that timers posted to the outgoing CPU
+will not fire until late in the CPU-hotplug process.
+The problem is that if a notifier is waiting on an SRCU grace period,
+that grace period is waiting on a timer, and that timer is stranded on the
+outgoing CPU, then the notifier will never be awakened, in other words,
+deadlock has occurred.
+This same situation of course also prohibits <tt>srcu_barrier()</tt>
+from being invoked from CPU-hotplug notifiers.
 
 <p>
 SRCU also differs from other RCU flavors in that SRCU's expedited and

Documentation/RCU/stallwarn.txt

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diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt
index 073dbc1..1ab70c3 100644
--- a/Documentation/RCU/stallwarn.txt
+++ b/Documentation/RCU/stallwarn.txt
@@ -219,17 +219,18 @@ an estimate of the total number of RCU callbacks queued across all CPUs
 In kernels with CONFIG_RCU_FAST_NO_HZ, more information is printed
 for each CPU:
 
-	0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 softirq=82/543 last_accelerate: a345/d342 nonlazy_posted: 25 .D
+	0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 softirq=82/543 last_accelerate: a345/d342 Nonlazy posted: ..D
 
 The "last_accelerate:" prints the low-order 16 bits (in hex) of the
 jiffies counter when this CPU last invoked rcu_try_advance_all_cbs()
 from rcu_needs_cpu() or last invoked rcu_accelerate_cbs() from
-rcu_prepare_for_idle().  The "nonlazy_posted:" prints the number
-of non-lazy callbacks posted since the last call to rcu_needs_cpu().
-Finally, an "L" indicates that there are currently no non-lazy callbacks
-("." is printed otherwise, as shown above) and "D" indicates that
-dyntick-idle processing is enabled ("." is printed otherwise, for example,
-if disabled via the "nohz=" kernel boot parameter).
+rcu_prepare_for_idle().  The "Nonlazy posted:" indicates lazy-callback
+status, so that an "l" indicates that all callbacks were lazy at the start
+of the last idle period and an "L" indicates that there are currently
+no non-lazy callbacks (in both cases, "." is printed otherwise, as
+shown above) and "D" indicates that dyntick-idle processing is enabled
+("." is printed otherwise, for example, if disabled via the "nohz="
+kernel boot parameter).
 
 If the grace period ends just as the stall warning starts printing,
 there will be a spurious stall-warning message, which will include

Documentation/RCU/torture.txt

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diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index 55918b5..a41a038 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -10,173 +10,8 @@ status messages via printk(), which can be examined via the dmesg
 command (perhaps grepping for "torture").  The test is started
 when the module is loaded, and stops when the module is unloaded.
 
-
-MODULE PARAMETERS
-
-This module has the following parameters:
-
-fqs_duration	Duration (in microseconds) of artificially induced bursts
-		of force_quiescent_state() invocations.  In RCU
-		implementations having force_quiescent_state(), these
-		bursts help force races between forcing a given grace
-		period and that grace period ending on its own.
-
-fqs_holdoff	Holdoff time (in microseconds) between consecutive calls
-		to force_quiescent_state() within a burst.
-
-fqs_stutter	Wait time (in seconds) between consecutive bursts
-		of calls to force_quiescent_state().
-
-gp_normal	Make the fake writers use normal synchronous grace-period
-		primitives.
-
-gp_exp		Make the fake writers use expedited synchronous grace-period
-		primitives.  If both gp_normal and gp_exp are set, or
-		if neither gp_normal nor gp_exp are set, then randomly
-		choose the primitive so that about 50% are normal and
-		50% expedited.  By default, neither are set, which
-		gives best overall test coverage.
-
-irqreader	Says to invoke RCU readers from irq level.  This is currently
-		done via timers.  Defaults to "1" for variants of RCU that
-		permit this.  (Or, more accurately, variants of RCU that do
-		-not- permit this know to ignore this variable.)
-
-n_barrier_cbs	If this is nonzero, RCU barrier testing will be conducted,
-		in which case n_barrier_cbs specifies the number of
-		RCU callbacks (and corresponding kthreads) to use for
-		this testing.  The value cannot be negative.  If you
-		specify this to be non-zero when torture_type indicates a
-		synchronous RCU implementation (one for which a member of
-		the synchronize_rcu() rather than the call_rcu() family is
-		used -- see the documentation for torture_type below), an
-		error will be reported and no testing will be carried out.
-
-nfakewriters	This is the number of RCU fake writer threads to run.  Fake
-		writer threads repeatedly use the synchronous "wait for
-		current readers" function of the interface selected by
-		torture_type, with a delay between calls to allow for various
-		different numbers of writers running in parallel.
-		nfakewriters defaults to 4, which provides enough parallelism
-		to trigger special cases caused by multiple writers, such as
-		the synchronize_srcu() early return optimization.
-
-nreaders	This is the number of RCU reading threads supported.
-		The default is twice the number of CPUs.  Why twice?
-		To properly exercise RCU implementations with preemptible
-		read-side critical sections.
-
-onoff_interval
-		The number of seconds between each attempt to execute a
-		randomly selected CPU-hotplug operation.  Defaults to
-		zero, which disables CPU hotplugging.  In HOTPLUG_CPU=n
-		kernels, rcutorture will silently refuse to do any
-		CPU-hotplug operations regardless of what value is
-		specified for onoff_interval.
-
-onoff_holdoff	The number of seconds to wait until starting CPU-hotplug
-		operations.  This would normally only be used when
-		rcutorture was built into the kernel and started
-		automatically at boot time, in which case it is useful
-		in order to avoid confusing boot-time code with CPUs
-		coming and going.
-
-shuffle_interval
-		The number of seconds to keep the test threads affinitied
-		to a particular subset of the CPUs, defaults to 3 seconds.
-		Used in conjunction with test_no_idle_hz.
-
-shutdown_secs	The number of seconds to run the test before terminating
-		the test and powering off the system.  The default is
-		zero, which disables test termination and system shutdown.
-		This capability is useful for automated testing.
-
-stall_cpu	The number of seconds that a CPU should be stalled while
-		within both an rcu_read_lock() and a preempt_disable().
-		This stall happens only once per rcutorture run.
-		If you need multiple stalls, use modprobe and rmmod to
-		repeatedly run rcutorture.  The default for stall_cpu
-		is zero, which prevents rcutorture from stalling a CPU.
-
-		Note that attempts to rmmod rcutorture while the stall
-		is ongoing will hang, so be careful what value you
-		choose for this module parameter!  In addition, too-large
-		values for stall_cpu might well induce failures and
-		warnings in other parts of the kernel.  You have been
-		warned!
-
-stall_cpu_holdoff
-		The number of seconds to wait after rcutorture starts
-		before stalling a CPU.  Defaults to 10 seconds.
-
-stat_interval	The number of seconds between output of torture
-		statistics (via printk()).  Regardless of the interval,
-		statistics are printed when the module is unloaded.
-		Setting the interval to zero causes the statistics to
-		be printed -only- when the module is unloaded, and this
-		is the default.
-
-stutter		The length of time to run the test before pausing for this
-		same period of time.  Defaults to "stutter=5", so as
-		to run and pause for (roughly) five-second intervals.
-		Specifying "stutter=0" causes the test to run continuously
-		without pausing, which is the old default behavior.
-
-test_boost	Whether or not to test the ability of RCU to do priority
-		boosting.  Defaults to "test_boost=1", which performs
-		RCU priority-inversion testing only if the selected
-		RCU implementation supports priority boosting.  Specifying
-		"test_boost=0" never performs RCU priority-inversion
-		testing.  Specifying "test_boost=2" performs RCU
-		priority-inversion testing even if the selected RCU
-		implementation does not support RCU priority boosting,
-		which can be used to test rcutorture's ability to
-		carry out RCU priority-inversion testing.
-
-test_boost_interval
-		The number of seconds in an RCU priority-inversion test
-		cycle.	Defaults to "test_boost_interval=7".  It is
-		usually wise for this value to be relatively prime to
-		the value selected for "stutter".
-
-test_boost_duration
-		The number of seconds to do RCU priority-inversion testing
-		within any given "test_boost_interval".  Defaults to
-		"test_boost_duration=4".
-
-test_no_idle_hz	Whether or not to test the ability of RCU to operate in
-		a kernel that disables the scheduling-clock interrupt to
-		idle CPUs.  Boolean parameter, "1" to test, "0" otherwise.
-		Defaults to omitting this test.
-
-torture_type	The type of RCU to test, with string values as follows:
-
-		"rcu":  rcu_read_lock(), rcu_read_unlock() and call_rcu(),
-			along with expedited, synchronous, and polling
-			variants.
-
-		"rcu_bh": rcu_read_lock_bh(), rcu_read_unlock_bh(), and
-			call_rcu_bh(), along with expedited and synchronous
-			variants.
-
-		"rcu_busted": This tests an intentionally incorrect version
-			of RCU in order to help test rcutorture itself.
-
-		"srcu": srcu_read_lock(), srcu_read_unlock() and
-			call_srcu(), along with expedited and
-			synchronous variants.
-
-		"sched": preempt_disable(), preempt_enable(), and
-			call_rcu_sched(), along with expedited,
-			synchronous, and polling variants.
-
-		"tasks": voluntary context switch and call_rcu_tasks(),
-			along with expedited and synchronous variants.
-
-		Defaults to "rcu".
-
-verbose		Enable debug printk()s.  Default is disabled.
-
+Module parameters are prefixed by "rcutorture." in
+Documentation/admin-guide/kernel-parameters.txt.
 
 OUTPUT
 

Documentation/RCU/whatisRCU.txt

View file

diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index 4a68543..1ace208 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -302,7 +302,7 @@ rcu_dereference()
 	must prohibit.	The rcu_dereference_protected() variant takes
 	a lockdep expression to indicate which locks must be acquired
 	by the caller. If the indicated protection is not provided,
-	a lockdep splat is emitted.  See RCU/Design/Requirements.html
+	a lockdep splat is emitted.  See RCU/Design/Requirements/Requirements.html
 	and the API's code comments for more details and example usage.
 
 The following diagram shows how each API communicates among the
@@ -560,7 +560,7 @@ presents two such "toy" implementations of RCU, one that is implemented
 in terms of familiar locking primitives, and another that more closely
 resembles "classic" RCU.  Both are way too simple for real-world use,
 lacking both functionality and performance.  However, they are useful
-in getting a feel for how RCU works.  See kernel/rcupdate.c for a
+in getting a feel for how RCU works.  See kernel/rcu/update.c for a
 production-quality implementation, and see:
 
 	http://www.rdrop.com/users/paulmck/RCU

Documentation/admin-guide/kernel-parameters.txt

View file

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index bcf2cd5..74dddbf 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3658,19 +3658,6 @@
 			latencies, which will choose a value aligned
 			with the appropriate hardware boundaries.
 
-	rcutree.jiffies_till_sched_qs= [KNL]
-			Set required age in jiffies for a
-			given grace period before RCU starts
-			soliciting quiescent-state help from
-			rcu_note_context_switch().  If not specified, the
-			kernel will calculate a value based on the most
-			recent settings of rcutree.jiffies_till_first_fqs
-			and rcutree.jiffies_till_next_fqs.
-			This calculated value may be viewed in
-			rcutree.jiffies_to_sched_qs.  Any attempt to
-			set rcutree.jiffies_to_sched_qs will be
-			cheerfully overwritten.
-
 	rcutree.jiffies_till_first_fqs= [KNL]
 			Set delay from grace-period initialization to
 			first attempt to force quiescent states.
@@ -3682,6 +3669,20 @@
 			quiescent states.  Units are jiffies, minimum
 			value is one, and maximum value is HZ.
 
+	rcutree.jiffies_till_sched_qs= [KNL]
+			Set required age in jiffies for a
+			given grace period before RCU starts
+			soliciting quiescent-state help from
+			rcu_note_context_switch() and cond_resched().
+			If not specified, the kernel will calculate
+			a value based on the most recent settings
+			of rcutree.jiffies_till_first_fqs
+			and rcutree.jiffies_till_next_fqs.
+			This calculated value may be viewed in
+			rcutree.jiffies_to_sched_qs.  Any attempt to set
+			rcutree.jiffies_to_sched_qs will be cheerfully
+			overwritten.
+
 	rcutree.kthread_prio= 	 [KNL,BOOT]
 			Set the SCHED_FIFO priority of the RCU per-CPU
 			kthreads (rcuc/N). This value is also used for
@@ -3725,6 +3726,11 @@
 			This wake_up() will be accompanied by a
 			WARN_ONCE() splat and an ftrace_dump().
 
+	rcutree.sysrq_rcu= [KNL]
+			Commandeer a sysrq key to dump out Tree RCU's
+			rcu_node tree with an eye towards determining
+			why a new grace period has not yet started.
+
 	rcuperf.gp_async= [KNL]
 			Measure performance of asynchronous
 			grace-period primitives such as call_rcu().

MAINTAINERS

View file

diff --git a/MAINTAINERS b/MAINTAINERS
index fbbb962..ea60bf1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10827,6 +10827,12 @@ F:	drivers/power/supply/bq27xxx_battery_i2c.c
 F:	drivers/power/supply/isp1704_charger.c
 F:	drivers/power/supply/rx51_battery.c
 
+NOLIBC HEADER FILE
+M:	Willy Tarreau <[email protected]>
+S:	Maintained
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git
+F:	tools/include/nolibc/
+
 NTB AMD DRIVER
 M:	Shyam Sundar S K <[email protected]>
 L:	[email protected]

include/asm-generic/bug.h

View file

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 20561a6..0e9bd9c 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -211,9 +211,6 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
 /*
  * WARN_ON_SMP() is for cases that the warning is either
  * meaningless for !SMP or may even cause failures.
- * This is usually used for cases that we have
- * WARN_ON(!spin_is_locked(&lock)) checks, as spin_is_locked()
- * returns 0 for uniprocessor settings.
  * It can also be used with values that are only defined
  * on SMP:
  *

include/linux/rcu_node_tree.h

View file

diff --git a/include/linux/rcu_node_tree.h b/include/linux/rcu_node_tree.h
index 426cee6..b8e094b 100644
--- a/include/linux/rcu_node_tree.h
+++ b/include/linux/rcu_node_tree.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * RCU node combining tree definitions.  These are used to compute
  * global attributes while avoiding common-case global contention.  A key
@@ -11,23 +12,9 @@

This diff is incomplete. Download the complete patch.