Commit 94e4dcc7 authored by Ingo Molnar's avatar Ingo Molnar

Merge branch 'for-mingo' of...

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU and LKMM commits from Paul E. McKenney:

 - An LKMM commit adding support for synchronize_srcu_expedited()
 - A couple of straggling RCU flavor consolidation updates
 - Documentation updates.
 - Miscellaneous fixes
 - SRCU updates
 - RCU CPU stall-warning updates
 - Torture-test updates
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents e53f31bf 91df49e1
......@@ -155,8 +155,7 @@ keeping lock contention under control at all tree levels regardless
of the level of loading on the system.
</p><p>RCU updaters wait for normal grace periods by registering
RCU callbacks, either directly via <tt>call_rcu()</tt> and
friends (namely <tt>call_rcu_bh()</tt> and <tt>call_rcu_sched()</tt>),
RCU callbacks, either directly via <tt>call_rcu()</tt>
or indirectly via <tt>synchronize_rcu()</tt> and friends.
RCU callbacks are represented by <tt>rcu_head</tt> structures,
which are queued on <tt>rcu_data</tt> structures while they are
......
......@@ -56,6 +56,7 @@ sections.
RCU-preempt Expedited Grace Periods</a></h2>
<p>
<tt>CONFIG_PREEMPT=y</tt> kernels implement RCU-preempt.
The overall flow of the handling of a given CPU by an RCU-preempt
expedited grace period is shown in the following diagram:
......@@ -139,6 +140,7 @@ or offline, among other things.
RCU-sched Expedited Grace Periods</a></h2>
<p>
<tt>CONFIG_PREEMPT=n</tt> kernels implement RCU-sched.
The overall flow of the handling of a given CPU by an RCU-sched
expedited grace period is shown in the following diagram:
......@@ -146,7 +148,7 @@ expedited grace period is shown in the following diagram:
<p>
As with RCU-preempt, RCU-sched's
<tt>synchronize_sched_expedited()</tt> ignores offline and
<tt>synchronize_rcu_expedited()</tt> ignores offline and
idle CPUs, again because they are in remotely detectable
quiescent states.
However, because the
......
......@@ -34,12 +34,11 @@ Similarly, any code that happens before the beginning of a given RCU grace
period is guaranteed to see the effects of all accesses following the end
of that grace period that are within RCU read-side critical sections.
<p>This guarantee is particularly pervasive for <tt>synchronize_sched()</tt>,
for which RCU-sched read-side critical sections include any region
<p>Note well that RCU-sched read-side critical sections include any region
of code for which preemption is disabled.
Given that each individual machine instruction can be thought of as
an extremely small region of preemption-disabled code, one can think of
<tt>synchronize_sched()</tt> as <tt>smp_mb()</tt> on steroids.
<tt>synchronize_rcu()</tt> as <tt>smp_mb()</tt> on steroids.
<p>RCU updaters use this guarantee by splitting their updates into
two phases, one of which is executed before the grace period and
......
......@@ -81,18 +81,19 @@ currently executing on some other CPU. We therefore cannot free
up any data structures used by the old NMI handler until execution
of it completes on all other CPUs.
One way to accomplish this is via synchronize_sched(), perhaps as
One way to accomplish this is via synchronize_rcu(), perhaps as
follows:
unset_nmi_callback();
synchronize_sched();
synchronize_rcu();
kfree(my_nmi_data);
This works because synchronize_sched() blocks until all CPUs complete
any preemption-disabled segments of code that they were executing.
Since NMI handlers disable preemption, synchronize_sched() is guaranteed
This works because (as of v4.20) synchronize_rcu() blocks until all
CPUs complete any preemption-disabled segments of code that they were
executing.
Since NMI handlers disable preemption, synchronize_rcu() is guaranteed
not to return until all ongoing NMI handlers exit. It is therefore safe
to free up the handler's data as soon as synchronize_sched() returns.
to free up the handler's data as soon as synchronize_rcu() returns.
Important note: for this to work, the architecture in question must
invoke nmi_enter() and nmi_exit() on NMI entry and exit, respectively.
......
......@@ -86,10 +86,8 @@ even on a UP system. So do not do it! Even on a UP system, the RCU
infrastructure -must- respect grace periods, and -must- invoke callbacks
from a known environment in which no locks are held.
It -is- safe for synchronize_sched() and synchronize_rcu_bh() to return
immediately on an UP system. It is also safe for synchronize_rcu()
to return immediately on UP systems, except when running preemptable
RCU.
Note that it -is- safe for synchronize_rcu() to return immediately on
UP systems, including !PREEMPT SMP builds running on UP systems.
Quick Quiz #3: Why can't synchronize_rcu() return immediately on
UP systems running preemptable RCU?
......
......@@ -182,16 +182,13 @@ over a rather long period of time, but improvements are always welcome!
when publicizing a pointer to a structure that can
be traversed by an RCU read-side critical section.
5. If call_rcu(), or a related primitive such as call_rcu_bh(),
call_rcu_sched(), or call_srcu() is used, the callback function
will be called from softirq context. In particular, it cannot
block.
5. If call_rcu() or call_srcu() is used, the callback function will
be called from softirq context. In particular, it cannot block.
6. Since synchronize_rcu() can block, it cannot be called from
any sort of irq context. The same rule applies for
synchronize_rcu_bh(), synchronize_sched(), synchronize_srcu(),
synchronize_rcu_expedited(), synchronize_rcu_bh_expedited(),
synchronize_sched_expedite(), and synchronize_srcu_expedited().
6. Since synchronize_rcu() can block, it cannot be called
from any sort of irq context. The same rule applies
for synchronize_srcu(), synchronize_rcu_expedited(), and
synchronize_srcu_expedited().
The expedited forms of these primitives have the same semantics
as the non-expedited forms, but expediting is both expensive and
......@@ -212,20 +209,20 @@ over a rather long period of time, but improvements are always welcome!
of the system, especially to real-time workloads running on
the rest of the system.
7. If the updater uses call_rcu() or synchronize_rcu(), then the
corresponding readers must use rcu_read_lock() and
rcu_read_unlock(). If the updater uses call_rcu_bh() or
synchronize_rcu_bh(), then the corresponding readers must
use rcu_read_lock_bh() and rcu_read_unlock_bh(). If the
updater uses call_rcu_sched() or synchronize_sched(), then
the corresponding readers must disable preemption, possibly
by calling rcu_read_lock_sched() and rcu_read_unlock_sched().
If the updater uses synchronize_srcu() or call_srcu(), then
the corresponding readers must use srcu_read_lock() and
7. As of v4.20, a given kernel implements only one RCU flavor,
which is RCU-sched for PREEMPT=n and RCU-preempt for PREEMPT=y.
If the updater uses call_rcu() or synchronize_rcu(),
then the corresponding readers my use rcu_read_lock() and
rcu_read_unlock(), rcu_read_lock_bh() and rcu_read_unlock_bh(),
or any pair of primitives that disables and re-enables preemption,
for example, rcu_read_lock_sched() and rcu_read_unlock_sched().
If the updater uses synchronize_srcu() or call_srcu(),
then the corresponding readers must use srcu_read_lock() and
srcu_read_unlock(), and with the same srcu_struct. The rules for
the expedited primitives are the same as for their non-expedited
counterparts. Mixing things up will result in confusion and
broken kernels.
broken kernels, and has even resulted in an exploitable security
issue.
One exception to this rule: rcu_read_lock() and rcu_read_unlock()
may be substituted for rcu_read_lock_bh() and rcu_read_unlock_bh()
......@@ -288,8 +285,7 @@ over a rather long period of time, but improvements are always welcome!
d. Periodically invoke synchronize_rcu(), permitting a limited
number of updates per grace period.
The same cautions apply to call_rcu_bh(), call_rcu_sched(),
call_srcu(), and kfree_rcu().
The same cautions apply to call_srcu() and kfree_rcu().
Note that although these primitives do take action to avoid memory
exhaustion when any given CPU has too many callbacks, a determined
......@@ -322,7 +318,7 @@ over a rather long period of time, but improvements are always welcome!
11. Any lock acquired by an RCU callback must be acquired elsewhere
with softirq disabled, e.g., via spin_lock_irqsave(),
spin_lock_bh(), etc. Failing to disable irq on a given
spin_lock_bh(), etc. Failing to disable softirq on a given
acquisition of that lock will result in deadlock as soon as
the RCU softirq handler happens to run your RCU callback while
interrupting that acquisition's critical section.
......@@ -335,13 +331,16 @@ over a rather long period of time, but improvements are always welcome!
must use whatever locking or other synchronization is required
to safely access and/or modify that data structure.
RCU callbacks are -usually- executed on the same CPU that executed
the corresponding call_rcu(), call_rcu_bh(), or call_rcu_sched(),
but are by -no- means guaranteed to be. For example, if a given
CPU goes offline while having an RCU callback pending, then that
RCU callback will execute on some surviving CPU. (If this was
not the case, a self-spawning RCU callback would prevent the
victim CPU from ever going offline.)
Do not assume that RCU callbacks will be executed on the same
CPU that executed the corresponding call_rcu() or call_srcu().
For example, if a given CPU goes offline while having an RCU
callback pending, then that RCU callback will execute on some
surviving CPU. (If this was not the case, a self-spawning RCU
callback would prevent the victim CPU from ever going offline.)
Furthermore, CPUs designated by rcu_nocbs= might well -always-
have their RCU callbacks executed on some other CPUs, in fact,
for some real-time workloads, this is the whole point of using
the rcu_nocbs= kernel boot parameter.
13. Unlike other forms of RCU, it -is- permissible to block in an
SRCU read-side critical section (demarked by srcu_read_lock()
......@@ -381,11 +380,11 @@ over a rather long period of time, but improvements are always welcome!
SRCU's expedited primitive (synchronize_srcu_expedited())
never sends IPIs to other CPUs, so it is easier on
real-time workloads than is synchronize_rcu_expedited(),
synchronize_rcu_bh_expedited() or synchronize_sched_expedited().
real-time workloads than is synchronize_rcu_expedited().
Note that rcu_dereference() and rcu_assign_pointer() relate to
SRCU just as they do to other forms of RCU.
Note that rcu_assign_pointer() relates to SRCU just as it does to
other forms of RCU, but instead of rcu_dereference() you should
use srcu_dereference() in order to avoid lockdep splats.
14. The whole point of call_rcu(), synchronize_rcu(), and friends
is to wait until all pre-existing readers have finished before
......@@ -405,6 +404,9 @@ over a rather long period of time, but improvements are always welcome!
read-side critical sections. It is the responsibility of the
RCU update-side primitives to deal with this.
For SRCU readers, you can use smp_mb__after_srcu_read_unlock()
immediately after an srcu_read_unlock() to get a full barrier.
16. Use CONFIG_PROVE_LOCKING, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and the
__rcu sparse checks to validate your RCU code. These can help
find problems as follows:
......@@ -428,22 +430,19 @@ over a rather long period of time, but improvements are always welcome!
These debugging aids can help you find problems that are
otherwise extremely difficult to spot.
17. If you register a callback using call_rcu(), call_rcu_bh(),
call_rcu_sched(), or call_srcu(), and pass in a function defined
within a loadable module, then it in necessary to wait for
all pending callbacks to be invoked after the last invocation
and before unloading that module. Note that it is absolutely
-not- sufficient to wait for a grace period! The current (say)
synchronize_rcu() implementation waits only for all previous
callbacks registered on the CPU that synchronize_rcu() is running
on, but it is -not- guaranteed to wait for callbacks registered
on other CPUs.
17. If you register a callback using call_rcu() or call_srcu(), and
pass in a function defined within a loadable module, then it in
necessary to wait for all pending callbacks to be invoked after
the last invocation and before unloading that module. Note that
it is absolutely -not- sufficient to wait for a grace period!
The current (say) synchronize_rcu() implementation is -not-
guaranteed to wait for callbacks registered on other CPUs.
Or even on the current CPU if that CPU recently went offline
and came back online.
You instead need to use one of the barrier functions:
o call_rcu() -> rcu_barrier()
o call_rcu_bh() -> rcu_barrier()
o call_rcu_sched() -> rcu_barrier()
o call_srcu() -> srcu_barrier()
However, these barrier functions are absolutely -not- guaranteed
......
......@@ -52,10 +52,10 @@ o If I am running on a uniprocessor kernel, which can only do one
o How can I see where RCU is currently used in the Linux kernel?
Search for "rcu_read_lock", "rcu_read_unlock", "call_rcu",
"rcu_read_lock_bh", "rcu_read_unlock_bh", "call_rcu_bh",
"srcu_read_lock", "srcu_read_unlock", "synchronize_rcu",
"synchronize_net", "synchronize_srcu", and the other RCU
primitives. Or grab one of the cscope databases from:
"rcu_read_lock_bh", "rcu_read_unlock_bh", "srcu_read_lock",
"srcu_read_unlock", "synchronize_rcu", "synchronize_net",
"synchronize_srcu", and the other RCU primitives. Or grab one
of the cscope databases from:
http://www.rdrop.com/users/paulmck/RCU/linuxusage/rculocktab.html
......
......@@ -351,3 +351,106 @@ garbage values.
In short, rcu_dereference() is -not- optional when you are going to
dereference the resulting pointer.
WHICH MEMBER OF THE rcu_dereference() FAMILY SHOULD YOU USE?
First, please avoid using rcu_dereference_raw() and also please avoid
using rcu_dereference_check() and rcu_dereference_protected() with a
second argument with a constant value of 1 (or true, for that matter).
With that caution out of the way, here is some guidance for which
member of the rcu_dereference() to use in various situations:
1. If the access needs to be within an RCU read-side critical
section, use rcu_dereference(). With the new consolidated
RCU flavors, an RCU read-side critical section is entered
using rcu_read_lock(), anything that disables bottom halves,
anything that disables interrupts, or anything that disables
preemption.
2. If the access might be within an RCU read-side critical section
on the one hand, or protected by (say) my_lock on the other,
use rcu_dereference_check(), for example:
p1 = rcu_dereference_check(p->rcu_protected_pointer,
lockdep_is_held(&my_lock));
3. If the access might be within an RCU read-side critical section
on the one hand, or protected by either my_lock or your_lock on
the other, again use rcu_dereference_check(), for example:
p1 = rcu_dereference_check(p->rcu_protected_pointer,
lockdep_is_held(&my_lock) ||
lockdep_is_held(&your_lock));
4. If the access is on the update side, so that it is always protected
by my_lock, use rcu_dereference_protected():
p1 = rcu_dereference_protected(p->rcu_protected_pointer,
lockdep_is_held(&my_lock));
This can be extended to handle multiple locks as in #3 above,
and both can be extended to check other conditions as well.
5. If the protection is supplied by the caller, and is thus unknown
to this code, that is the rare case when rcu_dereference_raw()
is appropriate. In addition, rcu_dereference_raw() might be
appropriate when the lockdep expression would be excessively
complex, except that a better approach in that case might be to
take a long hard look at your synchronization design. Still,
there are data-locking cases where any one of a very large number
of locks or reference counters suffices to protect the pointer,
so rcu_dereference_raw() does have its place.
However, its place is probably quite a bit smaller than one
might expect given the number of uses in the current kernel.
Ditto for its synonym, rcu_dereference_check( ... , 1), and
its close relative, rcu_dereference_protected(... , 1).
SPARSE CHECKING OF RCU-PROTECTED POINTERS
The sparse static-analysis tool checks for direct access to RCU-protected
pointers, which can result in "interesting" bugs due to compiler
optimizations involving invented loads and perhaps also load tearing.
For example, suppose someone mistakenly does something like this:
p = q->rcu_protected_pointer;
do_something_with(p->a);
do_something_else_with(p->b);
If register pressure is high, the compiler might optimize "p" out
of existence, transforming the code to something like this:
do_something_with(q->rcu_protected_pointer->a);
do_something_else_with(q->rcu_protected_pointer->b);
This could fatally disappoint your code if q->rcu_protected_pointer
changed in the meantime. Nor is this a theoretical problem: Exactly
this sort of bug cost Paul E. McKenney (and several of his innocent
colleagues) a three-day weekend back in the early 1990s.
Load tearing could of course result in dereferencing a mashup of a pair
of pointers, which also might fatally disappoint your code.
These problems could have been avoided simply by making the code instead
read as follows:
p = rcu_dereference(q->rcu_protected_pointer);
do_something_with(p->a);
do_something_else_with(p->b);
Unfortunately, these sorts of bugs can be extremely hard to spot during
review. This is where the sparse tool comes into play, along with the
"__rcu" marker. If you mark a pointer declaration, whether in a structure
or as a formal parameter, with "__rcu", which tells sparse to complain if
this pointer is accessed directly. It will also cause sparse to complain
if a pointer not marked with "__rcu" is accessed using rcu_dereference()
and friends. For example, ->rcu_protected_pointer might be declared as
follows:
struct foo __rcu *rcu_protected_pointer;
Use of "__rcu" is opt-in. If you choose not to use it, then you should
ignore the sparse warnings.
......@@ -83,16 +83,15 @@ Pseudo-code using rcu_barrier() is as follows:
2. Execute rcu_barrier().
3. Allow the module to be unloaded.
There are also rcu_barrier_bh(), rcu_barrier_sched(), and srcu_barrier()
functions for the other flavors of RCU, and you of course must match
the flavor of rcu_barrier() with that of call_rcu(). If your module
uses multiple flavors of call_rcu(), then it must also use multiple
There is also an srcu_barrier() function for SRCU, and you of course
must match the flavor of rcu_barrier() with that of call_rcu(). If your
module uses multiple flavors of call_rcu(), then it must also use multiple
flavors of rcu_barrier() when unloading that module. For example, if
it uses call_rcu_bh(), call_srcu() on srcu_struct_1, and call_srcu() on
it uses call_rcu(), call_srcu() on srcu_struct_1, and call_srcu() on
srcu_struct_2(), then the following three lines of code will be required
when unloading:
1 rcu_barrier_bh();
1 rcu_barrier();
2 srcu_barrier(&srcu_struct_1);
3 srcu_barrier(&srcu_struct_2);
......@@ -185,12 +184,12 @@ module invokes call_rcu() from timers, you will need to first cancel all
the timers, and only then invoke rcu_barrier() to wait for any remaining
RCU callbacks to complete.
Of course, if you module uses call_rcu_bh(), you will need to invoke
rcu_barrier_bh() before unloading. Similarly, if your module uses
call_rcu_sched(), you will need to invoke rcu_barrier_sched() before
unloading. If your module uses call_rcu(), call_rcu_bh(), -and-
call_rcu_sched(), then you will need to invoke each of rcu_barrier(),
rcu_barrier_bh(), and rcu_barrier_sched().
Of course, if you module uses call_rcu(), you will need to invoke
rcu_barrier() before unloading. Similarly, if your module uses
call_srcu(), you will need to invoke srcu_barrier() before unloading,
and on the same srcu_struct structure. If your module uses call_rcu()
-and- call_srcu(), then you will need to invoke rcu_barrier() -and-
srcu_barrier().
Implementing rcu_barrier()
......@@ -223,8 +222,8 @@ shown below. Note that the final "1" in on_each_cpu()'s argument list
ensures that all the calls to rcu_barrier_func() will have completed
before on_each_cpu() returns. Line 9 then waits for the completion.
This code was rewritten in 2008 to support rcu_barrier_bh() and
rcu_barrier_sched() in addition to the original rcu_barrier().
This code was rewritten in 2008 and several times thereafter, but this
still gives the general idea.
The rcu_barrier_func() runs on each CPU, where it invokes call_rcu()
to post an RCU callback, as follows:
......
......@@ -310,7 +310,7 @@ reader, updater, and reclaimer.
rcu_assign_pointer()
+--------+
+--------+
+---------------------->| reader |---------+
| +--------+ |
| | |
......@@ -318,12 +318,12 @@ reader, updater, and reclaimer.
| | | rcu_read_lock()
| | | rcu_read_unlock()
| rcu_dereference() | |
+---------+ | |
| updater |<---------------------+ |
+---------+ V
+---------+ | |
| updater |<----------------+ |
+---------+ V
| +-----------+
+----------------------------------->| reclaimer |
+-----------+
+-----------+
Defer:
synchronize_rcu() & call_rcu()
......
......@@ -3623,7 +3623,9 @@
see CONFIG_RAS_CEC help text.
rcu_nocbs= [KNL]
The argument is a cpu list, as described above.
The argument is a cpu list, as described above,
except that the string "all" can be used to
specify every CPU on the system.
In kernels built with CONFIG_RCU_NOCB_CPU=y, set
the specified list of CPUs to be no-callback CPUs.
......
......@@ -56,6 +56,23 @@ Barriers:
smp_mb__{before,after}_atomic()
TYPES (signed vs unsigned)
-----
While atomic_t, atomic_long_t and atomic64_t use int, long and s64
respectively (for hysterical raisins), the kernel uses -fno-strict-overflow
(which implies -fwrapv) and defines signed overflow to behave like
2s-complement.
Therefore, an explicitly unsigned variant of the atomic ops is strictly
unnecessary and we can simply cast, there is no UB.
There was a bug in UBSAN prior to GCC-8 that would generate UB warnings for
signed types.
With this we also conform to the C/C++ _Atomic behaviour and things like
P1236R1.
SEMANTICS
---------
......
......@@ -243,10 +243,10 @@ Optimization
^^^^^^^^^^^^
The Kprobe-optimizer doesn't insert the jump instruction immediately;
rather, it calls synchronize_sched() for safety first, because it's
rather, it calls synchronize_rcu() for safety first, because it's
possible for a CPU to be interrupted in the middle of executing the
optimized region [3]_. As you know, synchronize_sched() can ensure
that all interruptions that were active when synchronize_sched()
optimized region [3]_. As you know, synchronize_rcu() can ensure
that all interruptions that were active when synchronize_rcu()
was called are done, but only if CONFIG_PREEMPT=n. So, this version
of kprobe optimization supports only kernels with CONFIG_PREEMPT=n [4]_.
......
......@@ -493,10 +493,8 @@ CPU 에게 기대할 수 있는 최소한의 보장사항 몇가지가 있습니
이 타입의 오퍼레이션은 단방향의 투과성 배리어처럼 동작합니다. ACQUIRE
오퍼레이션 뒤의 모든 메모리 오퍼레이션들이 ACQUIRE 오퍼레이션 후에
일어난 것으로 시스템의 나머지 컴포넌트들에 보이게 될 것이 보장됩니다.
LOCK 오퍼레이션과 smp_load_acquire(), smp_cond_acquire() 오퍼레이션도
ACQUIRE 오퍼레이션에 포함됩니다. smp_cond_acquire() 오퍼레이션은 컨트롤
의존성과 smp_rmb() 를 사용해서 ACQUIRE 의 의미적 요구사항(semantic)을
충족시킵니다.
LOCK 오퍼레이션과 smp_load_acquire(), smp_cond_load_acquire() 오퍼레이션도
ACQUIRE 오퍼레이션에 포함됩니다.
ACQUIRE 오퍼레이션 앞의 메모리 오퍼레이션들은 ACQUIRE 오퍼레이션 완료 후에
수행된 것처럼 보일 수 있습니다.
......@@ -2146,33 +2144,40 @@ set_current_state() 는 다음의 것들로 감싸질 수도 있습니다:
event_indicated = 1;
wake_up_process(event_daemon);
wake_up() 류에 의해 쓰기 메모리 배리어가 내포됩니다. 만약 그것들이 뭔가를
깨운다면요. 이 배리어는 태스크 상태가 지워지기 전에 수행되므로, 이벤트를
알리기 위한 STORE 와 태스크 상태를 TASK_RUNNING 으로 설정하는 STORE 사이에
위치하게 됩니다.
wake_up() 이 무언가를 깨우게 되면, 이 함수는 범용 메모리 배리어를 수행합니다.
이 함수가 아무것도 깨우지 않는다면 메모리 배리어는 수행될 수도, 수행되지 않을
수도 있습니다; 이 경우에 메모리 배리어를 수행할 거라 오해해선 안됩니다. 이
배리어는 태스크 상태가 접근되기 전에 수행되는데, 자세히 말하면 이 이벤트를
알리기 위한 STORE 와 TASK_RUNNING 으로 상태를 쓰는 STORE 사이에 수행됩니다:
CPU 1 CPU 2
CPU 1 (Sleeper) CPU 2 (Waker)
=============================== ===============================
set_current_state(); STORE event_indicated
smp_store_mb(); wake_up();
STORE current->state <쓰기 배리어>
<범용 배리어> STORE current->state
LOAD event_indicated
STORE current->state ...
<범용 배리어> <범용 배리어>
LOAD event_indicated if ((LOAD task->state) & TASK_NORMAL)
STORE task->state
한번더 말합니다만, 이 쓰기 메모리 배리어는 이 코드가 정말로 뭔가를 깨울 때에만
실행됩니다. 이걸 설명하기 위해, X 와 Y 는 모두 0 으로 초기화 되어 있다는 가정
하에 아래의 이벤트 시퀀스를 생각해 봅시다:
여기서 "task" 는 깨어나지는 쓰레드이고 CPU 1 의 "current" 와 같습니다.
반복하지만, wake_up() 이 무언가를 정말 깨운다면 범용 메모리 배리어가 수행될
것이 보장되지만, 그렇지 않다면 그런 보장이 없습니다. 이걸 이해하기 위해, X 와
Y 는 모두 0 으로 초기화 되어 있다는 가정 하에 아래의 이벤트 시퀀스를 생각해
봅시다:
CPU 1 CPU 2
=============================== ===============================
X = 1; STORE event_indicated
X = 1; Y = 1;
smp_mb(); wake_up();
Y = 1; wait_event(wq, Y == 1);
wake_up(); load from Y sees 1, no memory barrier
load from X might see 0
LOAD Y LOAD X
정말로 깨우기가 행해졌다면, 두 로드 중 (최소한) 하나는 1 을 보게 됩니다.
반면에, 실제 깨우기가 행해지지 않았다면, 두 로드 모두 0을 볼 수도 있습니다.
위 예제에서의 경우와 달리 깨우기가 정말로 행해졌다면, CPU 2 의 X 로드는 1 을
본다고 보장될 수 있을 겁니다.
wake_up_process() 는 항상 범용 메모리 배리어를 수행합니다. 이 배리어 역시
태스크 상태가 접근되기 전에 수행됩니다. 특히, 앞의 예제 코드에서 wake_up() 이
wake_up_process() 로 대체된다면 두 로드 중 하나는 1을 볼 것이 보장됩니다.
사용 가능한 깨우기류 함수들로 다음과 같은 것들이 있습니다:
......@@ -2192,6 +2197,8 @@ wake_up() 류에 의해 쓰기 메모리 배리어가 내포됩니다. 만약
wake_up_poll();
wake_up_process();
메모리 순서규칙 관점에서, 이 함수들은 모두 wake_up() 과 같거나 보다 강한 순서
보장을 제공합니다.
[!] 잠재우는 코드와 깨우는 코드에 내포되는 메모리 배리어들은 깨우기 전에
이루어진 스토어를 잠재우는 코드가 set_current_state() 를 호출한 후에 행하는
......
......@@ -8993,7 +8993,7 @@ R: Daniel Lustig <dlustig@nvidia.com>
L: linux-kernel@vger.kernel.org
L: linux-arch@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: tools/memory-model/
F: Documentation/atomic_bitops.txt
F: Documentation/atomic_t.txt
......@@ -13041,9 +13041,9 @@ M: Josh Triplett <josh@joshtriplett.org>
R: Steven Rostedt <rostedt@goodmis.org>
R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
R: Lai Jiangshan <jiangshanlai@gmail.com>
L: linux-kernel@vger.kernel.org
L: rcu@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: tools/testing/selftests/rcutorture
RDC R-321X SoC
......@@ -13089,10 +13089,10 @@ R: Steven Rostedt <rostedt@goodmis.org>
R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
R: Lai Jiangshan <jiangshanlai@gmail.com>
R: Joel Fernandes <joel@joelfernandes.org>
L: linux-kernel@vger.kernel.org
L: rcu@vger.kernel.org
W: http://www.rdrop.com/users/paulmck/RCU/
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: Documentation/RCU/
X: Documentation/RCU/torture.txt
F: include/linux/rcu*
......@@ -14244,10 +14244,10 @@ M: "Paul E. McKenney" <paulmck@linux.ibm.com>
M: Josh Triplett <josh@joshtriplett.org>
R: Steven Rostedt <rostedt@goodmis.org>
R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
L: linux-kernel@vger.kernel.org
L: rcu@vger.kernel.org
W: http://www.rdrop.com/users/paulmck/RCU/
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: include/linux/srcu*.h
F: kernel/rcu/srcu*.c
......@@ -15694,7 +15694,7 @@ M: "Paul E. McKenney" <paulmck@linux.ibm.com>
M: Josh Triplett <josh@joshtriplett.org>
L: linux-kernel@vger.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: Documentation/RCU/torture.txt
F: kernel/torture.c
F: kernel/rcu/rcutorture.c
......
......@@ -388,7 +388,7 @@ static void nvme_free_ns_head(struct kref *ref)
nvme_mpath_remove_disk(head);
ida_simple_remove(&head->subsys->ns_ida, head->instance);
list_del_init(&head->entry);
cleanup_srcu_struct_quiesced(&head->srcu);
cleanup_srcu_struct(&head->srcu);
nvme_put_subsystem(head->subsys);
kfree(head);
}
......
......@@ -878,9 +878,11 @@ static inline void rcu_head_init(struct rcu_head *rhp)
static inline bool
rcu_head_after_call_rcu(struct rcu_head *rhp, rcu_callback_t f)
{
if (READ_ONCE(rhp->func) == f)
rcu_callback_t func = READ_ONCE(rhp->func);
if (func == f)
return true;
WARN_ON_ONCE(READ_ONCE(rhp->func) != (rcu_callback_t)~0L);
WARN_ON_ONCE(func != (rcu_callback_t)~0L);
return false;
}
......
......@@ -56,45 +56,11 @@ struct srcu_struct { };
void call_srcu(struct srcu_struct *ssp, struct rcu_head *head,
void (*func)(struct rcu_head *head));
void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced);
void cleanup_srcu_struct(struct srcu_struct *ssp);
int __srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp);
void __srcu_read_unlock(struct srcu_struct *ssp, int idx) __releases(ssp);
void synchronize_srcu(struct srcu_struct *ssp);
/**
* cleanup_srcu_struct - deconstruct a sleep-RCU structure
* @ssp: structure to clean up.
*
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory.
*/
static inline void cleanup_srcu_struct(struct srcu_struct *ssp)
{
_cleanup_srcu_struct(ssp, false);
}
/**
* cleanup_srcu_struct_quiesced - deconstruct a quiesced sleep-RCU structure
* @ssp: structure to clean up.
*
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory. Also,
* all grace-period processing must have completed.
*
* "Completed" means that the last synchronize_srcu() and
* synchronize_srcu_expedited() calls must have returned before the call
* to cleanup_srcu_struct_quiesced(). It also means that the callback
* from the last call_srcu() must have been invoked before the call to
* cleanup_srcu_struct_quiesced(), but you can use srcu_barrier() to help
* with this last. Violating these rules will get you a WARN_ON() splat
* (with high probability, anyway), and will also cause the srcu_struct
* to be leaked.
*/
static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *ssp)
{
_cleanup_srcu_struct(ssp, true);
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
/**
......
......@@ -829,7 +829,9 @@ static void lock_torture_cleanup(void)
"End of test: SUCCESS");
kfree(cxt.lwsa);
cxt.lwsa = NULL;
kfree(cxt.lrsa);
cxt.lrsa = NULL;
end:
torture_cleanup_end();
......
......@@ -233,6 +233,7 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
#ifdef CONFIG_RCU_STALL_COMMON
extern int rcu_cpu_stall_suppress;
extern int rcu_cpu_stall_timeout;
int rcu_jiffies_till_stall_check(void);
#define rcu_ftrace_dump_stall_suppress() \
......
......@@ -494,6 +494,10 @@ rcu_perf_cleanup(void)
if (torture_cleanup_begin())
return;
if (!cur_ops) {
torture_cleanup_end();
return;
}
if (reader_tasks) {
for (i = 0; i < nrealreaders; i++)
......@@ -614,6 +618,7 @@ rcu_perf_init(void)
pr_cont("\n");
WARN_ON(!IS_MODULE(CONFIG_RCU_PERF_TEST));
firsterr = -EINVAL;
cur_ops = NULL;
goto unwind;
}
if (cur_ops->init)
......
......@@ -299,7 +299,6 @@ struct rcu_torture_ops {
int irq_capable;
int can_boost;
int extendables;
int ext_irq_conflict;
const char *name;
};
......@@ -592,12 +591,7 @@ static void srcu_torture_init(void)
static void srcu_torture_cleanup(void)
{
static DEFINE_TORTURE_RANDOM(rand);
if (torture_random(&rand) & 0x800)
cleanup_srcu_struct(&srcu_ctld);
else
cleanup_srcu_struct_quiesced(&srcu_ctld);
cleanup_srcu_struct(&srcu_ctld);
srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
}
......@@ -1160,7 +1154,7 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
unsigned long randmask2 = randmask1 >> 3;
WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
/* Most of the time lots of bits, half the time only one bit. */
/* Mostly only one bit (need preemption!), sometimes lots of bits. */
if (!(randmask1 & 0x7))
mask = mask & randmask2;
else
......@@ -1170,10 +1164,6 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
(!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
if ((mask & RCUTORTURE_RDR_IRQ) &&
!(mask & cur_ops->ext_irq_conflict) &&
(oldmask & cur_ops->ext_irq_conflict))
mask |= cur_ops->ext_irq_conflict; /* Or if readers object. */
return mask ?: RCUTORTURE_RDR_RCU;
}
......@@ -1848,7 +1838,7 @@ static int rcutorture_oom_notify(struct notifier_block *self,
WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
__func__);
rcu_torture_fwd_cb_hist();
rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat) / 2));
rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat)) / 2);
WRITE_ONCE(rcu_fwd_emergency_stop, true);
smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
pr_info("%s: Freed %lu RCU callbacks.\n",
......@@ -2094,6 +2084,10 @@ rcu_torture_cleanup(void)
cur_ops->cb_barrier();
return;
}
if (!cur_ops) {
torture_cleanup_end();
return;
}
rcu_torture_barrier_cleanup();
torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
......@@ -2267,6 +2261,7 @@ rcu_torture_init(void)
pr_cont("\n");
WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
firsterr = -EINVAL;
cur_ops = NULL;
goto unwind;
}
if (cur_ops->fqs == NULL && fqs_duration != 0) {
......
......@@ -76,19 +76,16 @@ EXPORT_SYMBOL_GPL(init_srcu_struct);
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory.
*/
void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
void cleanup_srcu_struct(struct srcu_struct *ssp)
{
WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]);
if (quiesced)
WARN_ON(work_pending(&ssp->srcu_work));
else
flush_work(&ssp->srcu_work);
flush_work(&ssp->srcu_work);
WARN_ON(ssp->srcu_gp_running);
WARN_ON(ssp->srcu_gp_waiting);
WARN_ON(ssp->srcu_cb_head);
WARN_ON(&ssp->srcu_cb_head != ssp->srcu_cb_tail);
}
EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
/*
* Removes the count for the old reader from the appropriate element of
......
......@@ -360,8 +360,14 @@ static unsigned long srcu_get_delay(struct srcu_struct *ssp)
return SRCU_INTERVAL;
}
/* Helper for cleanup_srcu_struct() and cleanup_srcu_struct_quiesced(). */
void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
/**
* cleanup_srcu_struct - deconstruct a sleep-RCU structure
* @ssp: structure to clean up.
*
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory.
*/
void cleanup_srcu_struct(struct srcu_struct *ssp)
{
int cpu;
......@@ -369,24 +375,14 @@ void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
return; /* Just leak it! */
if (WARN_ON(srcu_readers_active(ssp)))
return; /* Just leak it! */
if (quiesced) {
if (WARN_ON(delayed_work_pending(&ssp->work)))
return; /* Just leak it! */
} else {
flush_delayed_work(&ssp->work);
}
flush_delayed_work(&ssp->work);
for_each_possible_cpu(cpu) {
struct srcu_data *sdp = per_cpu_ptr(ssp->sda, cpu);
if (quiesced) {
if (WARN_ON(timer_pending(&sdp->delay_work)))
return; /* Just leak it! */
if (WARN_ON(work_pending(&sdp->work)))
return; /* Just leak it! */
} else {
del_timer_sync(&sdp->delay_work);
flush_work(&sdp->work);
}
del_timer_sync(&sdp->delay_work);
flush_work(&sdp->work);
if (WARN_ON(rcu_segcblist_n_cbs(&sdp->srcu_cblist)))
return; /* Forgot srcu_barrier(), so just leak it! */
}
if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
WARN_ON(srcu_readers_active(ssp))) {
......@@ -397,7 +393,7 @@ void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
free_percpu(ssp->sda);
ssp->sda = NULL;
}
EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
/*
* Counts the new reader in the appropriate per-CPU element of the
......
......@@ -52,7 +52,7 @@ void rcu_qs(void)
local_irq_save(flags);
if (rcu_ctrlblk.donetail != rcu_ctrlblk.curtail) {
rcu_ctrlblk.donetail = rcu_ctrlblk.curtail;
raise_softirq(RCU_SOFTIRQ);
raise_softirq_irqoff(RCU_SOFTIRQ);
}
local_irq_restore(flags);
}
......
This diff is collapsed.
......@@ -393,15 +393,13 @@ static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
int rcu_dynticks_snap(struct rcu_data *rdp);
/* Forward declarations for rcutree_plugin.h */
/* Forward declarations for tree_plugin.h */
static void rcu_bootup_announce(void);
static void rcu_qs(void);
static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
#ifdef CONFIG_HOTPLUG_CPU
static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
static void rcu_print_detail_task_stall(void);
static int rcu_print_task_stall(struct rcu_node *rnp);
static int rcu_print_task_exp_stall(struct rcu_node *rnp);
static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
static void rcu_flavor_sched_clock_irq(int user);
......@@ -418,9 +416,6 @@ static void rcu_prepare_for_idle(void);
static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
static bool rcu_preempt_need_deferred_qs(struct task_struct *t);
static void rcu_preempt_deferred_qs(struct task_struct *t);
static void print_cpu_stall_info_begin(void);
static void print_cpu_stall_info(int cpu);
static void print_cpu_stall_info_end(void);
static void zero_cpu_stall_ticks(struct rcu_data *rdp);
static bool rcu_nocb_cpu_needs_barrier(int cpu);
static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
......@@ -445,3 +440,10 @@ static void rcu_bind_gp_kthread(void);
static bool rcu_nohz_full_cpu(void);
static void rcu_dynticks_task_enter(void);
static void rcu_dynticks_task_exit(void);
/* Forward declarations for tree_stall.h */
static void record_gp_stall_check_time(void);
static void rcu_iw_handler(struct irq_work *iwp);
static void check_cpu_stall(struct rcu_data *rdp);
static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
const unsigned long gpssdelay);
......@@ -10,6 +10,7 @@
#include <linux/lockdep.h>
static void rcu_exp_handler(void *unused);
static int rcu_print_task_exp_stall(struct rcu_node *rnp);
/*
* Record the start of an expedited grace period.
......@@ -633,7 +634,7 @@ static void rcu_exp_handler(void *unused)
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->expmask & rdp->grpmask) {
rdp->deferred_qs = true;
WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, true);
t->rcu_read_unlock_special.b.exp_hint = true;
}
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
......@@ -648,7 +649,7 @@ static void rcu_exp_handler(void *unused)
*
* If the CPU is fully enabled (or if some buggy RCU-preempt
* read-side critical section is being used from idle), just
* invoke rcu_preempt_defer_qs() to immediately report the
* invoke rcu_preempt_deferred_qs() to immediately report the
* quiescent state. We cannot use rcu_read_unlock_special()
* because we are in an interrupt handler, which will cause that
* function to take an early exit without doing anything.
......@@ -670,6 +671,27 @@ static void sync_sched_exp_online_cleanup(int cpu)
{
}
/*
* Scan the current list of tasks blocked within RCU read-side critical
* sections, printing out the tid of each that is blocking the current
* expedited grace period.
*/
static int rcu_print_task_exp_stall(struct rcu_node *rnp)
{
struct task_struct *t;
int ndetected = 0;
if (!rnp->exp_tasks)
return 0;
t = list_entry(rnp->exp_tasks->prev,
struct task_struct, rcu_node_entry);
list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
pr_cont(" P%d", t->pid);
ndetected++;
}
return ndetected;
}
#else /* #ifdef CONFIG_PREEMPT_RCU */
/* Invoked on each online non-idle CPU for expedited quiescent state. */
......@@ -709,6 +731,16 @@ static void sync_sched_exp_online_cleanup(int cpu)
WARN_ON_ONCE(ret);
}
/*
* Because preemptible RCU does not exist, we never have to check for
* tasks blocked within RCU read-side critical sections that are
* blocking the current expedited grace period.
*/
static int rcu_print_task_exp_stall(struct rcu_node *rnp)
{
return 0;
}
#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
/**
......
......@@ -285,7 +285,7 @@ static void rcu_qs(void)
TPS("cpuqs"));
__this_cpu_write(rcu_data.cpu_no_qs.b.norm, false);
barrier(); /* Coordinate with rcu_flavor_sched_clock_irq(). */
current->rcu_read_unlock_special.b.need_qs = false;
WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, false);
}
}
......@@ -642,100 +642,6 @@ static void rcu_read_unlock_special(struct task_struct *t)
rcu_preempt_deferred_qs_irqrestore(t, flags);
}
/*
* Dump detailed information for all tasks blocking the current RCU
* grace period on the specified rcu_node structure.
*/
static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
{
unsigned long flags;
struct task_struct *t;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (!rcu_preempt_blocked_readers_cgp(rnp)) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
}
t = list_entry(rnp->gp_tasks->prev,
struct task_struct, rcu_node_entry);
list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
/*
* We could be printing a lot while holding a spinlock.
* Avoid triggering hard lockup.
*/
touch_nmi_watchdog();
sched_show_task(t);
}
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/*
* Dump detailed information for all tasks blocking the current RCU
* grace period.
*/
static void rcu_print_detail_task_stall(void)
{
struct rcu_node *rnp = rcu_get_root();
rcu_print_detail_task_stall_rnp(rnp);
rcu_for_each_leaf_node(rnp)
rcu_print_detail_task_stall_rnp(rnp);
}
static void rcu_print_task_stall_begin(struct rcu_node *rnp)
{
pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):",
rnp->level, rnp->grplo, rnp->grphi);
}
static void rcu_print_task_stall_end(void)
{
pr_cont("\n");
}
/*
* Scan the current list of tasks blocked within RCU read-side critical
* sections, printing out the tid of each.
*/
static int rcu_print_task_stall(struct rcu_node *rnp)
{
struct task_struct *t;
int ndetected = 0;
if (!rcu_preempt_blocked_readers_cgp(rnp))
return 0;
rcu_print_task_stall_begin(rnp);
t = list_entry(rnp->gp_tasks->prev,
struct task_struct, rcu_node_entry);
list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
pr_cont(" P%d", t->pid);
ndetected++;
}
rcu_print_task_stall_end();
return ndetected;
}
/*
* Scan the current list of tasks blocked within RCU read-side critical
* sections, printing out the tid of each that is blocking the current
* expedited grace period.
*/
static int rcu_print_task_exp_stall(struct rcu_node *rnp)
{
struct task_struct *t;
int ndetected = 0;
if (!rnp->exp_tasks)
return 0;
t = list_entry(rnp->exp_tasks->prev,
struct task_struct, rcu_node_entry);
list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
pr_cont(" P%d", t->pid);
ndetected++;
}
return ndetected;
}
/*
* Check that the list of blocked tasks for the newly completed grace
* period is in fact empty. It is a serious bug to complete a grace
......@@ -804,19 +710,25 @@ static void rcu_flavor_sched_clock_irq(int user)
/*
* Check for a task exiting while in a preemptible-RCU read-side
* critical section, clean up if so. No need to issue warnings,
* as debug_check_no_locks_held() already does this if lockdep
* is enabled.
* critical section, clean up if so. No need to issue warnings, as
* debug_check_no_locks_held() already does this if lockdep is enabled.
* Besides, if this function does anything other than just immediately
* return, there was a bug of some sort. Spewing warnings from this
* function is like as not to simply obscure important prior warnings.
*/
void exit_rcu(void)
{
struct task_struct *t = current;
if (likely(list_empty(&current->rcu_node_entry)))
if (unlikely(!list_empty(&current->rcu_node_entry))) {
t->rcu_read_lock_nesting = 1;
barrier();
WRITE_ONCE(t->rcu_read_unlock_special.b.blocked, true);
} else if (unlikely(t->rcu_read_lock_nesting)) {
t->rcu_read_lock_nesting = 1;
} else {
return;
t->rcu_read_lock_nesting = 1;
barrier();
t->rcu_read_unlock_special.b.blocked = true;
}
__rcu_read_unlock();
rcu_preempt_deferred_qs(current);
}
......@@ -979,33 +891,6 @@ static bool rcu_preempt_need_deferred_qs(struct task_struct *t)
}
static void rcu_preempt_deferred_qs(struct task_struct *t) { }
/*
* Because preemptible RCU does not exist, we never have to check for
* tasks blocked within RCU read-side critical sections.
*/
static void rcu_print_detail_task_stall(void)
{
}
/*
* Because preemptible RCU does not exist, we never have to check for
* tasks blocked within RCU read-side critical sections.
*/
static int rcu_print_task_stall(struct rcu_node *rnp)
{
return 0;
}
/*
* Because preemptible RCU does not exist, we never have to check for
* tasks blocked within RCU read-side critical sections that are
* blocking the current expedited grace period.
*/
static int rcu_print_task_exp_stall(struct rcu_node *rnp)
{
return 0;
}
/*
* Because there is no preemptible RCU, there can be no readers blocked,
* so there is no need to check for blocked tasks. So check only for
......@@ -1185,8 +1070,6 @@ static int rcu_boost_kthread(void *arg)
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
__releases(rnp->lock)
{
struct task_struct *t;
raw_lockdep_assert_held_rcu_node(rnp);
if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
......@@ -1200,9 +1083,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
if (rnp->exp_tasks == NULL)
rnp->boost_tasks = rnp->gp_tasks;
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
t = rnp->boost_kthread_task;
if (t)
rcu_wake_cond(t, rnp->boost_kthread_status);
rcu_wake_cond(rnp->boost_kthread_task,
rnp->boost_kthread_status);
} else {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
......@@ -1649,98 +1531,6 @@ static void rcu_cleanup_after_idle(void)
#endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */
#ifdef CONFIG_RCU_FAST_NO_HZ
static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
{
struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
sprintf(cp, "last_accelerate: %04lx/%04lx, Nonlazy posted: %c%c%c",
rdp->last_accelerate & 0xffff, jiffies & 0xffff,
".l"[rdp->all_lazy],
".L"[!rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)],
".D"[!rdp->tick_nohz_enabled_snap]);
}
#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */
static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
{
*cp = '\0';
}
#endif /* #else #ifdef CONFIG_RCU_FAST_NO_HZ */
/* Initiate the stall-info list. */
static void print_cpu_stall_info_begin(void)
{
pr_cont("\n");
}
/*
* Print out diagnostic information for the specified stalled CPU.
*
* If the specified CPU is aware of the current RCU grace period, then
* print the number of scheduling clock interrupts the CPU has taken
* during the time that it has been aware. Otherwise, print the number
* of RCU grace periods that this CPU is ignorant of, for example, "1"
* if the CPU was aware of the previous grace period.
*
* Also print out idle and (if CONFIG_RCU_FAST_NO_HZ) idle-entry info.
*/
static void print_cpu_stall_info(int cpu)
{
unsigned long delta;
char fast_no_hz[72];
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
char *ticks_title;
unsigned long ticks_value;
/*
* We could be printing a lot while holding a spinlock. Avoid
* triggering hard lockup.
*/
touch_nmi_watchdog();
ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq);
if (ticks_value) {
ticks_title = "GPs behind";
} else {
ticks_title = "ticks this GP";
ticks_value = rdp->ticks_this_gp;
}
print_cpu_stall_fast_no_hz(fast_no_hz, cpu);
delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq);
pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s\n",
cpu,
"O."[!!cpu_online(cpu)],
"o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
"N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)],
!IS_ENABLED(CONFIG_IRQ_WORK) ? '?' :
rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' :
"!."[!delta],
ticks_value, ticks_title,
rcu_dynticks_snap(rdp) & 0xfff,
rdp->dynticks_nesting, rdp->dynticks_nmi_nesting,
rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu),
READ_ONCE(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart,
fast_no_hz);
}
/* Terminate the stall-info list. */
static void print_cpu_stall_info_end(void)
{
pr_err("\t");
}
/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */
static void zero_cpu_stall_ticks(struct rcu_data *rdp)
{
rdp->ticks_this_gp = 0;
rdp->softirq_snap = kstat_softirqs_cpu(RCU_SOFTIRQ, smp_processor_id());
WRITE_ONCE(rdp->last_fqs_resched, jiffies);
}
#ifdef CONFIG_RCU_NOCB_CPU
/*
......@@ -1766,11 +1556,22 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp)
*/
/* Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters. */
/*
* Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters.
* The string after the "rcu_nocbs=" is either "all" for all CPUs, or a
* comma-separated list of CPUs and/or CPU ranges. If an invalid list is
* given, a warning is emitted and all CPUs are offloaded.
*/
static int __init rcu_nocb_setup(char *str)
{
alloc_bootmem_cpumask_var(&rcu_nocb_mask);
cpulist_parse(str, rcu_nocb_mask);
if (!strcasecmp(str, "all"))
cpumask_setall(rcu_nocb_mask);
else
if (cpulist_parse(str, rcu_nocb_mask)) {
pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n");
cpumask_setall(rcu_nocb_mask);
}
return 1;
}
__setup("rcu_nocbs=", rcu_nocb_setup);
......
This diff is collapsed.
......@@ -424,68 +424,11 @@ EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read);
#endif
#ifdef CONFIG_RCU_STALL_COMMON
#ifdef CONFIG_PROVE_RCU
#define RCU_STALL_DELAY_DELTA (5 * HZ)
#else
#define RCU_STALL_DELAY_DELTA 0
#endif
int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */
EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress);
static int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
module_param(rcu_cpu_stall_suppress, int, 0644);
int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
module_param(rcu_cpu_stall_timeout, int, 0644);
int rcu_jiffies_till_stall_check(void)
{
int till_stall_check = READ_ONCE(rcu_cpu_stall_timeout);
/*
* Limit check must be consistent with the Kconfig limits
* for CONFIG_RCU_CPU_STALL_TIMEOUT.
*/
if (till_stall_check < 3) {
WRITE_ONCE(rcu_cpu_stall_timeout, 3);
till_stall_check = 3;
} else if (till_stall_check > 300) {
WRITE_ONCE(rcu_cpu_stall_timeout, 300);
till_stall_check = 300;
}
return till_stall_check * HZ + RCU_STALL_DELAY_DELTA;
}
EXPORT_SYMBOL_GPL(rcu_jiffies_till_stall_check);
void rcu_sysrq_start(void)
{
if (!rcu_cpu_stall_suppress)
rcu_cpu_stall_suppress = 2;
}
void rcu_sysrq_end(void)
{
if (rcu_cpu_stall_suppress == 2)
rcu_cpu_stall_suppress = 0;
}
static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr)
{
rcu_cpu_stall_suppress = 1;
return NOTIFY_DONE;
}
static struct notifier_block rcu_panic_block = {
.notifier_call = rcu_panic,
};
static int __init check_cpu_stall_init(void)
{
atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block);
return 0;
}
early_initcall(check_cpu_stall_init);
#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
#ifdef CONFIG_TASKS_RCU
......
......@@ -88,6 +88,8 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
return false;
if (num_online_cpus() <= 1)
return false; /* Can't offline the last CPU. */
if (verbose > 1)
pr_alert("%s" TORTURE_FLAG
......
......@@ -56,7 +56,7 @@ struct clusterip_config {
#endif
enum clusterip_hashmode hash_mode; /* which hashing mode */
u_int32_t hash_initval; /* hash initialization */
struct rcu_head rcu; /* for call_rcu_bh */
struct rcu_head rcu; /* for call_rcu */
struct net *net; /* netns for pernet list */
char ifname[IFNAMSIZ]; /* device ifname */
};
......
......@@ -20,13 +20,17 @@ that litmus test to be exercised within the Linux kernel.
REQUIREMENTS
============
Version 7.49 of the "herd7" and "klitmus7" tools must be downloaded
separately:
Version 7.52 or higher of the "herd7" and "klitmus7" tools must be
downloaded separately:
https://github.com/herd/herdtools7
See "herdtools7/INSTALL.md" for installation instructions.
Note that although these tools usually provide backwards compatibility,
this is not absolutely guaranteed. Therefore, if a later version does
not work, please try using the exact version called out above.
==================
BASIC USAGE: HERD7
......@@ -221,8 +225,29 @@ The Linux-kernel memory model has the following limitations:
additional call_rcu() process to the site of the
emulated rcu-barrier().
e. Sleepable RCU (SRCU) is not modeled. It can be
emulated, but perhaps not simply.
e. Although sleepable RCU (SRCU) is now modeled, there
are some subtle differences between its semantics and
those in the Linux kernel. For example, the kernel
might interpret the following sequence as two partially
overlapping SRCU read-side critical sections:
1 r1 = srcu_read_lock(&my_srcu);
2 do_something_1();
3 r2 = srcu_read_lock(&my_srcu);
4 do_something_2();
5 srcu_read_unlock(&my_srcu, r1);
6 do_something_3();
7 srcu_read_unlock(&my_srcu, r2);
In contrast, LKMM will interpret this as a nested pair of
SRCU read-side critical sections, with the outer critical
section spanning lines 1-7 and the inner critical section
spanning lines 3-5.
This difference would be more of a concern had anyone
identified a reasonable use case for partially overlapping
SRCU read-side critical sections. For more information,
please see: https://paulmck.livejournal.com/40593.html
f. Reader-writer locking is not modeled. It can be
emulated in litmus tests using atomic read-modify-write
......
......@@ -33,8 +33,14 @@ enum Barriers = 'wmb (*smp_wmb*) ||
'after-unlock-lock (*smp_mb__after_unlock_lock*)
instructions F[Barriers]
(* SRCU *)
enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu
instructions SRCU[SRCU]
(* All srcu events *)
let Srcu = Srcu-lock | Srcu-unlock | Sync-srcu
(* Compute matching pairs of nested Rcu-lock and Rcu-unlock *)
let matched = let rec
let rcu-rscs = let rec
unmatched-locks = Rcu-lock \ domain(matched)
and unmatched-unlocks = Rcu-unlock \ range(matched)
and unmatched = unmatched-locks | unmatched-unlocks
......@@ -46,8 +52,27 @@ let matched = let rec
in matched
(* Validate nesting *)
flag ~empty Rcu-lock \ domain(matched) as unbalanced-rcu-locking
flag ~empty Rcu-unlock \ range(matched) as unbalanced-rcu-locking
flag ~empty Rcu-lock \ domain(rcu-rscs) as unbalanced-rcu-locking
flag ~empty Rcu-unlock \ range(rcu-rscs) as unbalanced-rcu-locking
(* Compute matching pairs of nested Srcu-lock and Srcu-unlock *)
let srcu-rscs = let rec
unmatched-locks = Srcu-lock \ domain(matched)
and unmatched-unlocks = Srcu-unlock \ range(matched)
and unmatched = unmatched-locks | unmatched-unlocks
and unmatched-po = ([unmatched] ; po ; [unmatched]) & loc
and unmatched-locks-to-unlocks =
([unmatched-locks] ; po ; [unmatched-unlocks]) & loc
and matched = matched | (unmatched-locks-to-unlocks \
(unmatched-po ; unmatched-po))
in matched
(* Validate nesting *)
flag ~empty Srcu-lock \ domain(srcu-rscs) as unbalanced-srcu-locking
flag ~empty Srcu-unlock \ range(srcu-rscs) as unbalanced-srcu-locking
(* Check for use of synchronize_srcu() inside an RCU critical section *)
flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep
(* Outermost level of nesting only *)
let crit = matched \ (po^-1 ; matched ; po^-1)
(* Validate SRCU dynamic match *)
flag ~empty different-values(srcu-rscs) as srcu-bad-nesting
......@@ -33,7 +33,7 @@ let mb = ([M] ; fencerel(Mb) ; [M]) |
([M] ; po? ; [LKW] ; fencerel(After-spinlock) ; [M]) |
([M] ; po ; [UL] ; (co | po) ; [LKW] ;
fencerel(After-unlock-lock) ; [M])
let gp = po ; [Sync-rcu] ; po?
let gp = po ; [Sync-rcu | Sync-srcu] ; po?
let strong-fence = mb | gp
......@@ -91,32 +91,47 @@ acyclic pb as propagation
(*******)
(*
* Effect of read-side critical section proceeds from the rcu_read_lock()
* onward on the one hand and from the rcu_read_unlock() backwards on the
* other hand.
* Effects of read-side critical sections proceed from the rcu_read_unlock()
* or srcu_read_unlock() backwards on the one hand, and from the
* rcu_read_lock() or srcu_read_lock() forwards on the other hand.
*
* In the definition of rcu-fence below, the po term at the left-hand side
* of each disjunct and the po? term at the right-hand end have been factored
* out. They have been moved into the definitions of rcu-link and rb.
* This was necessary in order to apply the "& loc" tests correctly.
*)
let rscs = po ; crit^-1 ; po?
let rcu-gp = [Sync-rcu] (* Compare with gp *)
let srcu-gp = [Sync-srcu]
let rcu-rscsi = rcu-rscs^-1
let srcu-rscsi = srcu-rscs^-1
(*
* The synchronize_rcu() strong fence is special in that it can order not
* one but two non-rf relations, but only in conjunction with an RCU
* read-side critical section.
*)
let rcu-link = hb* ; pb* ; prop
let rcu-link = po? ; hb* ; pb* ; prop ; po
(*
* Any sequence containing at least as many grace periods as RCU read-side
* critical sections (joined by rcu-link) acts as a generalized strong fence.
* Likewise for SRCU grace periods and read-side critical sections, provided
* the synchronize_srcu() and srcu_read_[un]lock() calls refer to the same
* struct srcu_struct location.
*)
let rec rcu-fence = gp |
(gp ; rcu-link ; rscs) |
(rscs ; rcu-link ; gp) |
(gp ; rcu-link ; rcu-fence ; rcu-link ; rscs) |
(rscs ; rcu-link ; rcu-fence ; rcu-link ; gp) |
let rec rcu-fence = rcu-gp | srcu-gp |
(rcu-gp ; rcu-link ; rcu-rscsi) |
((srcu-gp ; rcu-link ; srcu-rscsi) & loc) |
(rcu-rscsi ; rcu-link ; rcu-gp) |
((srcu-rscsi ; rcu-link ; srcu-gp) & loc) |
(rcu-gp ; rcu-link ; rcu-fence ; rcu-link ; rcu-rscsi) |
((srcu-gp ; rcu-link ; rcu-fence ; rcu-link ; srcu-rscsi) & loc) |
(rcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; rcu-gp) |
((srcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; srcu-gp) & loc) |
(rcu-fence ; rcu-link ; rcu-fence)
(* rb orders instructions just as pb does *)
let rb = prop ; rcu-fence ; hb* ; pb*
let rb = prop ; po ; rcu-fence ; po? ; hb* ; pb*
irreflexive rb as rcu
......
......@@ -47,6 +47,12 @@ rcu_read_unlock() { __fence{rcu-unlock}; }
synchronize_rcu() { __fence{sync-rcu}; }
synchronize_rcu_expedited() { __fence{sync-rcu}; }
// SRCU
srcu_read_lock(X) __srcu{srcu-lock}(X)
srcu_read_unlock(X,Y) { __srcu{srcu-unlock}(X,Y); }
synchronize_srcu(X) { __srcu{sync-srcu}(X); }
synchronize_srcu_expedited(X) { __srcu{sync-srcu}(X); }
// Atomic
atomic_read(X) READ_ONCE(*X)
atomic_set(X,V) { WRITE_ONCE(*X,V); }
......
......@@ -6,9 +6,6 @@
(*
* Generate coherence orders and handle lock operations
*
* Warning: spin_is_locked() crashes herd7 versions strictly before 7.48.
* spin_is_locked() is functional from herd7 version 7.49.
*)
include "cross.cat"
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Extract the number of CPUs expected from the specified Kconfig-file
# fragment by checking CONFIG_SMP and CONFIG_NR_CPUS. If the specified
......@@ -7,23 +8,9 @@
#
# Usage: configNR_CPUS.sh config-frag
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2013
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
cf=$1
if test ! -r $cf
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# config_override.sh base override
#
......@@ -6,23 +7,9 @@
# that conflict with any in override, concatenating what remains and
# sending the result to standard output.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2017
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
base=$1
if test -r $base
......
#!/bin/bash
# Usage: configcheck.sh .config .config-template
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# SPDX-License-Identifier: GPL-2.0+
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
# Usage: configcheck.sh .config .config-template
#
# Copyright (C) IBM Corporation, 2011
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
T=${TMPDIR-/tmp}/abat-chk-config.sh.$$
trap 'rm -rf $T' 0
......@@ -26,6 +14,7 @@ mkdir $T
cat $1 > $T/.config
cat $2 | sed -e 's/\(.*\)=n/# \1 is not set/' -e 's/^#CHECK#//' |
grep -v '^CONFIG_INITRAMFS_SOURCE' |
awk '
{
print "if grep -q \"" $0 "\" < '"$T/.config"'";
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Usage: configinit.sh config-spec-file build-output-dir results-dir
#
......@@ -14,23 +15,9 @@
# for example, "O=/tmp/foo". If this argument is omitted, the .config
# file will be generated directly in the current directory.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2013
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
T=${TMPDIR-/tmp}/configinit.sh.$$
trap 'rm -rf $T' 0
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Get an estimate of how CPU-hoggy to be.
#
# Usage: cpus2use.sh
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2013
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
ncpus=`grep '^processor' /proc/cpuinfo | wc -l`
idlecpus=`mpstat | tail -1 | \
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Shell functions for the rest of the scripts.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2013
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
# bootparam_hotplug_cpu bootparam-string
#
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Alternate sleeping and spinning on randomly selected CPUs. The purpose
# of this script is to inflict random OS jitter on a concurrently running
......@@ -11,23 +12,9 @@
# sleepmax: Maximum microseconds to sleep, defaults to one second.
# spinmax: Maximum microseconds to spin, defaults to one millisecond.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2016
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
me=$(($1 * 1000))
duration=$2
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Build a kvm-ready Linux kernel from the tree in the current directory.
#
# Usage: kvm-build.sh config-template build-dir resdir
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2011
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
config_template=${1}
if test -z "$config_template" -o ! -f "$config_template" -o ! -r "$config_template"
......
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0+
#
# Invoke a text editor on all console.log files for all runs with diagnostics,
# that is, on all such files having a console.log.diags counterpart.
......@@ -10,6 +11,10 @@
#
# The "directory" above should end with the date/time directory, for example,
# "tools/testing/selftests/rcutorture/res/2018.02.25-14:27:27".
#
# Copyright (C) IBM Corporation, 2018
#
# Author: Paul E. McKenney <paulmck@linux.ibm.com>
rundir="${1}"
if test -z "$rundir" -o ! -d "$rundir"
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Analyze a given results directory for locktorture progress.
#
# Usage: kvm-recheck-lock.sh resdir
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2014
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
i="$1"
if test -d "$i" -a -r "$i"
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Analyze a given results directory for rcutorture progress.
#
# Usage: kvm-recheck-rcu.sh resdir
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2014
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
i="$1"
if test -d "$i" -a -r "$i"
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Analyze a given results directory for rcuperf performance measurements,
# looking for ftrace data. Exits with 0 if data was found, analyzed, and
......@@ -7,23 +8,9 @@
#
# Usage: kvm-recheck-rcuperf-ftrace.sh resdir
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2016
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
i="$1"
. functions.sh
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Analyze a given results directory for rcuperf performance measurements.
#
# Usage: kvm-recheck-rcuperf.sh resdir
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2016
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
i="$1"
if test -d "$i" -a -r "$i"
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Given the results directories for previous KVM-based torture runs,
# check the build and console output for errors. Given a directory
......@@ -6,23 +7,9 @@
#
# Usage: kvm-recheck.sh resdir ...
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2011
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
PATH=`pwd`/tools/testing/selftests/rcutorture/bin:$PATH; export PATH
. functions.sh
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Run a kvm-based test of the specified tree on the specified configs.
# Fully automated run and error checking, no graphics console.
......@@ -20,23 +21,9 @@
#
# More sophisticated argument parsing is clearly needed.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2011
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
T=${TMPDIR-/tmp}/kvm-test-1-run.sh.$$
trap 'rm -rf $T' 0
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Run a series of tests under KVM. By default, this series is specified
# by the relevant CFLIST file, but can be overridden by the --configs
......@@ -6,23 +7,9 @@
#
# Usage: kvm.sh [ options ]
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2011
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
scriptname=$0
args="$*"
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Create an initrd directory if one does not already exist.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2013
#
# Author: Connor Shu <Connor.Shu@ibm.com>
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Check the build output from an rcutorture run for goodness.
# The "file" is a pathname on the local system, and "title" is
......@@ -8,23 +9,9 @@
#
# Usage: parse-build.sh file title
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2011
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
F=$1
title=$2
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Check the console output from an rcutorture run for oopses.
# The "file" is a pathname on the local system, and "title" is
......@@ -6,23 +7,9 @@
#
# Usage: parse-console.sh file title
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2011
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
T=${TMPDIR-/tmp}/parse-console.sh.$$
file="$1"
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Kernel-version-dependent shell functions for the rest of the scripts.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2014
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
# locktorture_param_onoff bootparam-string config-file
#
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Kernel-version-dependent shell functions for the rest of the scripts.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2013
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
# rcutorture_param_n_barrier_cbs bootparam-string
#
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+
#
# Torture-suite-dependent shell functions for the rest of the scripts.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, you can access it online at
# http://www.gnu.org/licenses/gpl-2.0.html.
#
# Copyright (C) IBM Corporation, 2015
#
# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
# Authors: Paul E. McKenney <paulmck@linux.ibm.com>
# per_version_boot_params bootparam-string config-file seconds
#
......
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