Paul Gortmaker [Wed, 19 Feb 2014 19:33:27 +0000 (14:33 -0500)]
rcu: Ensure kernel/rcu/rcu.h can be sourced/used stand-alone
The kbuild test bot uncovered an implicit dependence on the
trace header being present before rcu.h in ia64 allmodconfig
that looks like this:
In file included from kernel/ksysfs.c:22:0:
kernel/rcu/rcu.h: In function '__rcu_reclaim':
kernel/rcu/rcu.h:107:3: error: implicit declaration of function 'trace_rcu_invoke_kfree_callback' [-Werror=implicit-function-declaration]
kernel/rcu/rcu.h:112:3: error: implicit declaration of function 'trace_rcu_invoke_callback' [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors
Looking at other rcu.h users, we can find that they all
were sourcing the trace header in advance of rcu.h itself,
as seen in the context of this diff. There were also some
inconsistencies as to whether it was or wasn't sourced based
on the parent tracing Kconfig.
Rather than "fix" it at each use site, and have inconsistent
use based on whether "#ifdef CONFIG_RCU_TRACE" was used or not,
lets just source the trace header just once, in the actual consumer
of it, which is rcu.h itself. We include it unconditionally, as
build testing shows us that is a hard requirement for some files.
Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul Gortmaker [Tue, 11 Feb 2014 21:10:12 +0000 (16:10 -0500)]
rcu: Fix sparse warning for rcu_expedited from kernel/ksysfs.c
This commit fixes the follwoing warning:
kernel/ksysfs.c:143:5: warning: symbol 'rcu_expedited' was not declared. Should it be static?
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
[ paulmck: Moved the declaration to include/linux/rcupdate.h to avoid
including the RCU-internal rcu.h file outside of RCU. ] Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 12 Feb 2014 21:02:22 +0000 (13:02 -0800)]
notifier: Substitute rcu_access_pointer() for rcu_dereference_raw()
(Trivial patch.)
If the code is looking at the RCU-protected pointer itself, but not
dereferencing it, the rcu_dereference() functions can be downgraded
to rcu_access_pointer(). This commit makes this downgrade in
__blocking_notifier_call_chain() which simply compares the RCU-protected
pointer against NULL with no dereferencing.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit fixes a couple of typos and clarifies what happens when
the CPU chooses to execute a later lock acquisition before a prior
lock release, in particular, why deadlock is avoided.
Reported-by: Peter Hurley <peter@hurleysoftware.com> Reported-by: James Bottomley <James.Bottomley@HansenPartnership.com> Reported-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Tue, 11 Feb 2014 03:59:05 +0000 (19:59 -0800)]
rcutorture: Place kvm-test-1-run.sh output into res directory
The output of each kvm-test-1-run.sh script is placed into a file
whose name parallels that of the build directory. This means that
the kvm-test-1-run.sh output is overwritten by later run. This
commit therefore places the kvm-test-1-run.sh output into the
per-test-case directory in the "res" hierarchy.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul Bolle [Sun, 9 Feb 2014 02:06:57 +0000 (18:06 -0800)]
rcutorture: Rename TREE_RCU-Kconfig.txt
It used to be that:
git ls-files "*Kconfig*"
would find all Kconfig files and would only find Kconfig files. This
commit renames TREE_RCU-Kconfig.txt to TREE_RCU-kconfig.txt so that this
is once again true.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Although most torture tests will have some cleanup hook, it is possible
that one might not. This commit therefore enables graceful handling of
a NULL cleanup hook during torture-test shutdown.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit uses the standard software ploy of introducing another
level of indirection below the configs directory. This allows each
torture-test suite to have its own set of Kconfig files, boot parameters,
and version-specific scripts. Initially, we have only rcu, but lock
will follow soonish.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
rcutorture: Remove RCU dependencies from ver_functions.sh API
The current set of functions in ver_functions.sh have APIs that are
specific to RCU. This commit therefore makes an RCU-independent function
that outputs version-specific boot arguments. This has the benefit that
a test-type-independent call in kvm-test-1-rcu.sh can now handle any type
of test, given a test-type-specific set of files in a configs directory.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
rcutorture: Create CFcommon file for common Kconfig parameters
Currently, CONFIG_RCU_TORTURE_TEST=y is hardcoded into the
kvm-test-1-rcu.sh script and CONFIG_PRINTK_TIME=y is mentioned in each
and every configs file. This commit creates a CFcommon file for these
two Kconfig parameters, and modifies kvm-test-1-rcu.sh to copy this new
file into the .config file during the build. This change will allow
these scripts to operate on torture types other than just rcutorture.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
rcutorture: Create config files for scripted test-the-test testing
This commit adds a pair of files in the configs directory to allow
test-the-test runs of rcutorture via a "--configs BUSTED" argument to
the kvm.sh script.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit adds a deliberately buggy RCU implementation into rcutorture
to allow easy checking that rcutorture correctly flags buggy RCU
implementations.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit adds the locking counterpart to rcutorture.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Make n_lock_torture_errors and torture_spinlock static
as suggested by Fengguang Wu. ] Reviewed-by: Josh Triplett <josh@joshtriplett.org>
rcutorture: Stop generic kthreads in torture_cleanup()
The specific torture modules (like rcutorture) need to call
torture_cleanup() in any case, so this commit makes torture_cleanup()
deal with torture_shutdown_cleanup() and torture_stutter_cleanup() so
that the specific modules don't have to deal with these details.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Creation of kthreads is not RCU-specific, so this commit abstracts
out torture_create_kthread(), saving a few tens of lines of code in
the process.
This change requires modifying VERBOSE_TOROUT_ERRSTRING() to take a
non-const string, so that _torture_create_kthread() can avoid an
open-coded substitute.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Not all of the rcutorture kthreads waited for kthread_should_stop()
before returning from their top-level functions, and none of them
used torture_shutdown_absorb() properly. These problems can result in
segfaults and hangs at shutdown time, and some recent changes perturbed
timing sufficiently to make them much more probable. This commit
therefore creates a torture_kthread_stopping() function that does the
proper kthread shutdown dance in one centralized location.
Accommodate this grouping by making VERBOSE_TOROUT_STRING() capable of
taking a non-const string as its argument, which allows the new
torture_kthread_stopping() to pass its "title" argument directly to
the updated version of VERBOSE_TOROUT_STRING().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Fri, 31 Jan 2014 23:39:52 +0000 (15:39 -0800)]
rcutorture: Announce task creation
A few "stealth-start rcutorture kthreads" have accumulated over the years,
so this commit adds console-log announcements (but only if the torture
tests are running verbose).
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Fri, 31 Jan 2014 20:58:39 +0000 (12:58 -0800)]
rcutorture: Apply ACCESS_ONCE() to racy fullstop accesses
Because the fullstop variable can be accessed while it is being updated,
this commit avoids any resulting compiler mischief through use of
ACCESS_ONCE() for non-initialization accesses to this shared variable.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Fri, 31 Jan 2014 19:57:43 +0000 (11:57 -0800)]
rcutorture: Abstract stutter_wait()
Because stuttering the test load (stopping and restarting it) is useful
for non-RCU testing, this commit moves the load-stuttering functionality
to kernel/torture.c.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Fri, 31 Jan 2014 01:06:30 +0000 (17:06 -0800)]
rcutorture: Add diagnostic for unscheduled system shutdown
Currently, rcutorture can terminate via rmmod, via self-shutdown,
via something else shutting the system down, or of course the usual
catastrophic termination. The first two get flagged, so this commit adds
a message for the third. For the fourth, your warranty is void as always.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Thu, 30 Jan 2014 23:49:29 +0000 (15:49 -0800)]
rcutorture: Privatize fullstop
This commit introduces the torture_must_stop() function in order to
keep use of the fullstop variable local to kernel/torture.c. There
is also a torture_must_stop_irq() counterpart for use from RCU callbacks,
timeout handlers, and the like.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Thu, 30 Jan 2014 23:37:19 +0000 (15:37 -0800)]
rcutorture: Abstract torture_shutdown_notify()
Because handling the race between rmmod and system shutdown is not
specific to RCU, this commit abstracts torture_shutdown_notify(),
placing this code into kernel/torture.c. This change also allows
fullstop_mutex to be private to kernel/torture.c.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Thu, 30 Jan 2014 21:38:09 +0000 (13:38 -0800)]
rcutorture: Abstract torture-test initialization
This commit creates torture_init_begin() and torture_init_end() functions
to abstract locking and allow the torture_type and verbose variables
in kernel/torture.o to become static. With a bit more abstraction,
fullstop_mutex will also become static.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Tue, 28 Jan 2014 23:58:22 +0000 (15:58 -0800)]
rcutorture: Abstract torture_onoff()
Because online/offline torturing is not specific to RCU, this commit
abstracts it into the kernel/torture.c module to allow other torture
tests to use it.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Tue, 28 Jan 2014 23:29:21 +0000 (15:29 -0800)]
rcutorture: Abstract torture_shuffle()
The torture_shuffle() function forces each CPU in turn to go idle
periodically in order to check for problems interacting with per-CPU
variables and with dyntick-idle mode. Because this sort of debugging
is not specific to RCU, this commit abstracts that functionality.
This in turn requires abstracting some additional infrastructure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 29 Jan 2014 15:40:27 +0000 (07:40 -0800)]
rcutorture: Abstract torture_shutdown_absorb()
Because handling races between rmmod and normal shutdown is not specific
to rcutorture, this commit renames rcutorture_shutdown_absorb() to
torture_shutdown_absorb() and pulls it out into then kernel/torture.c
module. This implies pulling the fullstop mechanism into kernel/torture.c
as well.
The exporting of fullstop and fullstop_mutex is ugly and must die.
And it does in fact die in later commits that introduce higher-level
APIs that encapsulate both of these variables.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>`
Paul E. McKenney [Wed, 29 Jan 2014 15:30:50 +0000 (07:30 -0800)]
rcutorture: Abstract TOROUT_STRING() and friends
These diagnostic macros are not confined to torturing RCU, so this commit
makes them available to other torture tests. Also removed the do-while
from TOROUT_STRING() in response to checkpatch complaints.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Tue, 28 Jan 2014 00:27:00 +0000 (16:27 -0800)]
rcutorture: Abstract torture_param()
Create a torture_param() macro and apply it to rcutorture in order to
save a few lines of code. This same macro may be applied to other
torture frameworks.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Mon, 27 Jan 2014 20:31:20 +0000 (12:31 -0800)]
rcutorture: Don't create results directory for dryruns
This commit prevents the results directory from being created for
dryruns. However, a script generated from a dryrun will create
the results directory should it be run.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org
Paul E. McKenney [Mon, 27 Jan 2014 19:49:39 +0000 (11:49 -0800)]
rcutorture: Abstract rcu_torture_random()
Because rcu_torture_random() will be used by the locking equivalent to
rcutorture, pull it out into its own module. This new module cannot
be separately configured, instead, use the Kconfig "select" statement
from the Kconfig options of tests depending on it.
Suggested-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Sat, 18 Jan 2014 06:08:09 +0000 (22:08 -0800)]
rcutorture: Flag tests requiring more CPUs than are available
This commit adds a "(!)" flag after the number of CPUs required by a
given test if that test requires more than the available number of CPUs.
Note that these flags appear only when the number of CPUs is specified
using the --cpus argument. In the absence of a --cpus argument, no
tests are flagged.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
If one of the eight-CPU runs were to be moved into the first batch,
the test suite would complete in four batches rather than five.
This commit therefore uses a greedy algorithm to re-order the test
entries so that the sequential batching will produce an optimal schedule
in this case:
Paul E. McKenney [Fri, 17 Jan 2014 11:10:16 +0000 (03:10 -0800)]
rcutorture: Add dryrun capability
Actual rcutorture tests take considerable time and machine resources,
so it is inconvenient to actually do an rcutorture run when optimizing
the bin-packing algorithm. This commit therefore adds a --dryrun
argument, which defaults to doing a run, but for which "sched"
says to simply print the run schedule and "script" dumps the script
without running it.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 15 Jan 2014 23:48:41 +0000 (15:48 -0800)]
rcutorture: Enable concurrent rcutorture runs
The rcutorture tests run by default range from using one CPU to using
sixteen of them. Therefore, rcutorture testing could be sped up
significantly simply by running the kernels in parallel. Building
them in parallel is not all that helpful: "make -j" is usually a
better bet. So this commit takes a new "--cpus" argument that
specifies how many CPUs rcutorture is permitted to use for its
parallel runs. The default of zero does sequential runs as before.
The bin-packing is minimal, and will be grossly suboptimal for
some configurations. However, powers of two work reasonably well.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 15 Jan 2014 06:26:09 +0000 (22:26 -0800)]
rcutorture: Reduce SRCU-N number of CPUs
Both SRCU-P and SRCU-N specify eight CPUs, which results in four
iterations for a parallel run on 32 CPUs. This commit reduces SRCU-N
to four CPUs (but leaving SRCU-P at eight) to speed up parallel runs,
while maintaining essentially the same test coverage.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 15 Jan 2014 05:28:57 +0000 (21:28 -0800)]
rcutorture: Move common qemu flags to kvm-test-1.sh
Currently, most qemu flags are calculated in kvm-test-1-rcu.sh,
except that -nographics is set up by kvm.sh. This commit promotes
one-stop shopping by consolidating the determination of qemu flags into
kvm-test-1-rcu.sh.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Tue, 14 Jan 2014 07:16:55 +0000 (23:16 -0800)]
rcutorture: Allow kvm-test-1-rcu.sh to pause after build
Parallel rcutorture runs is valuable on large systems, but it is not a
good idea to do (say) five builds in parallel if each build believes it
has the whole system at its disposal, especially if the system is shared.
It is also bad to restrict the build to (say) a single CPU just because
the corresponding rcutorture run uses only a single CPU. This commit
therefore adds a kvm-test-1-rcu.sh ability to pause after the build
completes, which will allow kvm.sh to do a number of builds serially
(with each build thus having the full system at its disposal), then
allow the rcutorture runs to proceed in parallel.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Tue, 14 Jan 2014 06:57:48 +0000 (22:57 -0800)]
rcutorture: Move common boot flags to kvm-test-1-rcu.sh
Currently, most boot flags are calculated in kvm-test-1-rcu.sh, except
that rcutorture.test_no_idle_hz and rcutorture.verbose are set up by
kvm.sh. This commit promotes one-stop shopping by consolidating the
determination of boot flags into kvm-test-1-rcu.sh.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Thu, 19 Dec 2013 18:52:55 +0000 (10:52 -0800)]
rcutorture: Print script and arguments to standard output
Although the script name and arguments are logged in the results directory,
it is more convenient to see it in the output. This commit therefore
adds the output of this information.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Sometime problems can manifest themselves as unusually slow grace periods.
This commit therefore prints the number of rcutorture updates during the
test and the number per second. These statistics are harvested from the
config.out and qemu-cmd files, and are silently omitted if these files
are not available, as would be the case if there was a build failure or
a boot-time hang.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Mon, 18 Nov 2013 05:08:07 +0000 (21:08 -0800)]
rcu: Optimize RCU_FAST_NO_HZ for RCU_NOCB_CPU_ALL
If CONFIG_RCU_NOCB_CPU_ALL=y, then no CPU will ever have RCU callbacks
because these callbacks will instead be handled by the rcuo kthreads.
However, the current version of RCU_FAST_NO_HZ nevertheless checks for RCU
callbacks. This commit therefore creates static inline implementations
of rcu_prepare_for_idle() and rcu_cleanup_after_idle() that are no-ops
when CONFIG_RCU_NOCB_CPU_ALL=y.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Mon, 18 Nov 2013 03:27:16 +0000 (19:27 -0800)]
rcu: Optimize rcu_needs_cpu() for RCU_NOCB_CPU_ALL
If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_needs_cpu() will always
return false, however, the current version nevertheless checks
for RCU callbacks. This commit therefore creates a static inline
implementation of rcu_needs_cpu() that unconditionally returns false
when CONFIG_RCU_NOCB_CPU_ALL=y.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Mon, 18 Nov 2013 02:25:48 +0000 (18:25 -0800)]
rcu: Optimize rcu_is_nocb_cpu() for RCU_NOCB_CPU_ALL
If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_is_nocb_cpu() will always
return true, however, the current version nevertheless checks
rcu_nocb_mask. This commit therefore creates a static inline
implementation of rcu_is_nocb_cpu() that unconditionally returns
true when CONFIG_RCU_NOCB_CPU_ALL=y.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 12 Feb 2014 20:51:09 +0000 (12:51 -0800)]
fs: Substitute rcu_access_pointer() for rcu_dereference_raw()
(Trivial patch.)
If the code is looking at the RCU-protected pointer itself, but not
dereferencing it, the rcu_dereference() functions can be downgraded to
rcu_access_pointer(). This commit makes this downgrade in __alloc_fd(),
which simply compares the RCU-protected pointer against NULL with no
dereferencing.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Shaibal Dutta [Fri, 31 Jan 2014 19:53:06 +0000 (11:53 -0800)]
rcu: Move SRCU grace period work to power efficient workqueue
For better use of CPU idle time, allow the scheduler to select the CPU
on which the SRCU grace period work would be scheduled. This improves
idle residency time and conserves power.
This functionality is enabled when CONFIG_WQ_POWER_EFFICIENT is selected.
Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Shaibal Dutta <shaibal.dutta@broadcom.com>
[zoran.markovic@linaro.org: Rebased to latest kernel version. Added commit
message. Fixed code alignment.] Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul Bolle [Sun, 9 Feb 2014 13:35:11 +0000 (14:35 +0100)]
rcu: Disambiguate CONFIG_RCU_NOCB_CPUs
This commit fixes a grammar issue in the rcu_nohz_full_cpu() comment
header, so that it is clear that the plural is CPUs not Kconfig options.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Mon, 16 Dec 2013 21:24:32 +0000 (13:24 -0800)]
rcu: Define rcu_assign_pointer() in terms of smp_store_release()
The new smp_store_release() function provides better guarantees than did
rcu_assign_pointer(), and potentially less overhead on some architectures.
The guarantee that smp_store_release() provides that rcu_assign_pointer()
does that is obscure, but its lack could cause considerable confusion.
This guarantee is illustrated by the following code fragment:
struct foo {
int a;
int b;
int c;
struct foo *next;
};
struct foo foo1;
struct foo foo2;
struct foo __rcu *foop;
The current rcu_assign_pointer() semantics permit the BUG_ON() to
trigger because rcu_assign_pointer()'s smp_wmb() is not guaranteed to
order prior reads against later writes. This commit therefore upgrades
rcu_assign_pointer() from smp_wmb() to smp_store_release() to avoid this
counter-intuitive outcome.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Joe Perches [Fri, 6 Dec 2013 00:19:15 +0000 (16:19 -0800)]
rcu: Indentation and spacing fixes.
This commit outdents expression-statement macros, thus repairing a few
line-length complaints. Also fix some spacing errors called out by
checkpatch.pl.
Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Joe Perches [Thu, 5 Dec 2013 23:10:23 +0000 (15:10 -0800)]
rcu: Glue ASCII strings together
Split strings make it difficult to find the code that resulted in a
given console message, so this commit glues split strings back together
despite the resulting long lines.
Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Because jiffies is one of a very few variables marked "volatile", there
is no need to use ACCESS_ONCE() when accessing it. This commit therefore
removes the redundant ACCESS_ONCE() wrappers.
Reported by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
All of the RCU source files have the usual GPL header, which contains a
long-obsolete postal address for FSF. To avoid the need to track the
FSF office's movements, this commit substitutes the URL where GPL may
be found.
Reported-by: Greg KH <gregkh@linuxfoundation.org> Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
rcu: Add ACCESS_ONCE() to ->n_force_qs_lh accesses
The ->n_force_qs_lh field is accessed without the benefit of any
synchronization, so this commit adds the needed ACCESS_ONCE() wrappers.
Yes, increments to ->n_force_qs_lh can be lost, but contention should
be low and the field is strictly statistical in nature, so this is not
a problem.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Thu, 13 Feb 2014 04:19:47 +0000 (20:19 -0800)]
Documentation/memory-barriers.txt: Need barriers() for some control dependencies
Current compilers can "speculate" stores in the case where both legs
of the "if" statement start with identical stores. Because the stores
are identical, the compiler knows that the store will unconditionally
execute regardless of the "if" condition, and so the compiler is within
its rights to hoist the store to precede the condition. Such hoisting
destroys the control-dependency ordering. This ordering can be restored
by placing a barrier() at the beginning of each leg of the "if" statement.
This commit adds this requirement to the control-dependencies section.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The ACCESS_ONCE() primitive provides cache coherence, but the
documentation does not clearly state this. This commit therefore upgrades
the documentation.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
documentation: Document call_rcu() safety mechanisms and limitations
The call_rcu() family of primitives will take action to accelerate
grace periods when the number of callbacks pending on a given CPU
becomes excessive. Although this safety mechanism can be useful,
it is no substitute for users of call_rcu() having rate-limit controls
in place. This commit adds this nuance to the documentation.
Reported-by: "Michael S. Tsirkin" <mst@redhat.com> Reported-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Linus Torvalds [Sun, 16 Feb 2014 19:05:27 +0000 (11:05 -0800)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
"We have a small collection of fixes in my for-linus branch.
The big thing that stands out is a revert of a new ioctl. Users
haven't shipped yet in btrfs-progs, and Dave Sterba found a better way
to export the information"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: use right clone root offset for compressed extents
btrfs: fix null pointer deference at btrfs_sysfs_add_one+0x105
Btrfs: unset DCACHE_DISCONNECTED when mounting default subvol
Btrfs: fix max_inline mount option
Btrfs: fix a lockdep warning when cleaning up aborted transaction
Revert "btrfs: add ioctl to export size of global metadata reservation"
Linus Torvalds [Sun, 16 Feb 2014 19:03:58 +0000 (11:03 -0800)]
Merge tag 'dt-fixes-for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
Pull devicetree fixes from Rob Herring:
"Fix booting on PPC boards. Changes to of_match_node matching caused
the serial port on some PPC boards to stop working. Reverted the
change and reimplement to split matching between new style compatible
only matching and fallback to old matching algorithm"
* tag 'dt-fixes-for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
of: search the best compatible match first in __of_match_node()
Revert "OF: base: match each node compatible against all given matches first"
Kevin Hao [Fri, 14 Feb 2014 05:22:46 +0000 (13:22 +0800)]
of: search the best compatible match first in __of_match_node()
Currently, of_match_node compares each given match against all node's
compatible strings with of_device_is_compatible.
To achieve multiple compatible strings per node with ordering from
specific to generic, this requires given matches to be ordered from
specific to generic. For most of the drivers this is not true and also
an alphabetical ordering is more sane there.
Therefore, this patch introduces a function to match each of the node's
compatible strings against all given compatible matches without type and
name first, before checking the next compatible string. This implies
that node's compatibles are ordered from specific to generic while
given matches can be in any order. If we fail to find such a match
entry, then fall-back to the old method in order to keep compatibility.
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> Signed-off-by: Kevin Hao <haokexin@gmail.com> Tested-by: Stephen Chivers <schivers@csc.com> Signed-off-by: Rob Herring <robh@kernel.org>
Pull SCSI target fixes from Nicholas Bellinger:
"Mostly minor fixes this time to v3.14-rc1 related changes. Also
included is one fix for a free after use regression in persistent
reservations UNREGISTER logic that is CC'ed to >= v3.11.y stable"
* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
Target/sbc: Fix protection copy routine
IB/srpt: replace strict_strtoul() with kstrtoul()
target: Simplify command completion by removing CMD_T_FAILED flag
iser-target: Fix leak on failure in isert_conn_create_fastreg_pool
iscsi-target: Fix SNACK Type 1 + BegRun=0 handling
target: Fix missing length check in spc_emulate_evpd_83()
qla2xxx: Remove last vestiges of qla_tgt_cmd.cmd_list
target: Fix 32-bit + CONFIG_LBDAF=n link error w/ sector_div
target: Fix free-after-use regression in PR unregister
Linus Torvalds [Sun, 16 Feb 2014 00:06:12 +0000 (16:06 -0800)]
Merge branches 'irq-urgent-for-linus' and 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq update from Thomas Gleixner:
"Fix from the urgent branch: a trivial oneliner adding the missing
Kconfig dependency curing build failures which have been discovered by
several build robots.
The update in the irq-core branch provides a new function in the
irq/devres code, which is a prerequisite for driver developers to get
rid of boilerplate code all over the place.
Not a bugfix, but it has zero impact on the current kernel due to the
lack of users. It's simpler to provide the infrastructure to
interested parties via your tree than fulfilling the wishlist of
driver maintainers on which particular commit or tag this should be
based on"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq: Add missing irq_to_desc export for CONFIG_SPARSE_IRQ=n
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq: Add devm_request_any_context_irq()
Linus Torvalds [Sun, 16 Feb 2014 00:04:42 +0000 (16:04 -0800)]
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner:
"The following trilogy of patches brings you:
- fix for a long standing math overflow issue with HZ < 60
- an onliner fix for a corner case in the dreaded tick broadcast
mechanism affecting a certain range of AMD machines which are
infested with the infamous automagic C1E power control misfeature
- a fix for one of the ARM platforms which allows the kernel to
proceed and boot instead of stupidly panicing for no good reason.
The patch is slightly larger than necessary, but it's less ugly
than the alternative 5 liner"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick: Clear broadcast pending bit when switching to oneshot
clocksource: Kona: Print warning rather than panic
time: Fix overflow when HZ is smaller than 60
Linus Torvalds [Sat, 15 Feb 2014 23:03:34 +0000 (15:03 -0800)]
Merge tag 'trace-fixes-v3.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull twi tracing fixes from Steven Rostedt:
"Two urgent fixes in the tracing utility.
The first is a fix for the way the ring buffer stores timestamps.
After a restructure of the code was done, the ring buffer timestamp
logic missed the fact that the first event on a sub buffer is to have
a zero delta, as the full timestamp is stored on the sub buffer
itself. But because the delta was not cleared to zero, the timestamp
for that event will be calculated as the real timestamp + the delta
from the last timestamp. This can skew the timestamps of the events
and have them say they happened when they didn't really happen.
That's bad.
The second fix is for modifying the function graph caller site. When
the stop machine was removed from updating the function tracing code,
it missed updating the function graph call site location. It is still
modified as if it is being done via stop machine. But it's not. This
can lead to a GPF and kernel crash if the function graph call site
happens to lie between cache lines and one CPU is executing it while
another CPU is doing the update. It would be a very hard condition to
hit, but the result is severe enough to have it fixed ASAP"
* tag 'trace-fixes-v3.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace/x86: Use breakpoints for converting function graph caller
ring-buffer: Fix first commit on sub-buffer having non-zero delta
Linus Torvalds [Sat, 15 Feb 2014 23:02:28 +0000 (15:02 -0800)]
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 EFI fixes from Peter Anvin:
"A few more EFI-related fixes"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/efi: Check status field to validate BGRT header
x86/efi: Fix 32-bit fallout
Linus Torvalds [Sat, 15 Feb 2014 23:01:33 +0000 (15:01 -0800)]
Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC fixes from Kevin Hilman:
"A collection of ARM SoC fixes for v3.14-rc1.
Mostly a collection of Kconfig, device tree data and compilation fixes
along with fix to drivers/phy that fixes a boot regression on some
Marvell mvebu platforms"
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
dma: mv_xor: Silence a bunch of LPAE-related warnings
ARM: ux500: disable msp2 device tree node
ARM: zynq: Reserve not DMAable space in front of the kernel
ARM: multi_v7_defconfig: Select CONFIG_SOC_DRA7XX
ARM: imx6: Initialize low-power mode early again
ARM: pxa: fix various compilation problems
ARM: pxa: fix compilation problem on AM300EPD board
ARM: at91: add Atmel's SAMA5D3 Xplained board
spi/atmel: document clock properties
mmc: atmel-mci: document clock properties
ARM: at91: enable USB host on at91sam9n12ek board
ARM: at91/dt: fix sama5d3 ohci hclk clock reference
ARM: at91/dt: sam9263: fix compatibility string for the I2C
ata: sata_mv: Fix probe failures with optional phys
drivers: phy: Add support for optional phys
drivers: phy: Make NULL a valid phy reference
ARM: fix HAVE_ARM_TWD selection for OMAP and shmobile
ARM: moxart: move DMA_OF selection to driver
ARM: hisi: fix kconfig warning on HAVE_ARM_TWD
Btrfs: use right clone root offset for compressed extents
For non compressed extents, iterate_extent_inodes() gives us offsets
that take into account the data offset from the file extent items, while
for compressed extents it doesn't. Therefore we have to adjust them before
placing them in a send clone instruction. Not doing this adjustment leads to
the receiving end requesting for a wrong a file range to the clone ioctl,
which results in different file content from the one in the original send
root.
Issue reproducible with the following excerpt from the test I made for
xfstests:
Wolfram Sang [Thu, 13 Feb 2014 20:36:29 +0000 (21:36 +0100)]
i2c: mv64xxx: refactor message start to ensure proper initialization
Because the offload mechanism can fall back to a standard transfer,
having two seperate initialization states is unfortunate. Let's just
have one state which does things consistently. This fixes a bug where
some preparation was missing when the fallback happened. And it makes
the code much easier to follow. To implement this, we put the check
if offload is possible at the top of the offload setup function.
Linus Torvalds [Sat, 15 Feb 2014 00:15:45 +0000 (16:15 -0800)]
Merge tag 'usb-3.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
Pull USB fixes from Greg KH:
"Here is a bunch of USB fixes for 3.14-rc3. Most of these are xhci
reverts, fixing a bunch of reported issues with USB 3 host controller
issues that loads of people have been hitting (with the exception of
kernel developers, all of our machines seem to be working fine, which
is why these took so long to get resolved...)
There are some other minor fixes and new device ids, as ususal. All
have been in linux-next successfully"
* tag 'usb-3.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (22 commits)
usb: option: blacklist ZTE MF667 net interface
Revert "usb: xhci: Link TRB must not occur within a USB payload burst"
Revert "xhci: Avoid infinite loop when sg urb requires too many trbs"
Revert "xhci: Set scatter-gather limit to avoid failed block writes."
xhci 1.0: Limit arbitrarily-aligned scatter gather.
Modpost: fixed USB alias generation for ranges including 0x9 and 0xA
usb: core: Fix potential memory leak adding dyn USBdevice IDs
USB: ftdi_sio: add Tagsys RFID Reader IDs
usb: qcserial: add Netgear Aircard 340U
usb-storage: enable multi-LUN scanning when needed
USB: simple: add Dynastream ANT USB-m Stick device support
usb-storage: add unusual-devs entry for BlackBerry 9000
usb-storage: restrict bcdDevice range for Super Top in Cypress ATACB
usb: phy: move some error messages to debug
usb: ftdi_sio: add Mindstorms EV3 console adapter
usb: dwc2: fix memory corruption in dwc2 driver
usb: dwc2: fix role switch breakage
usb: dwc2: bail out early when booting with "nousb"
Revert "xhci: replace xhci_read_64() with readq()"
Revert "xhci: replace xhci_write_64() with writeq()"
...
Linus Torvalds [Sat, 15 Feb 2014 00:15:03 +0000 (16:15 -0800)]
Merge tag 'tty-3.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial driver fixes from Greg KH:
"Here are a small number of tty/serial driver fixes to resolve reported
issues with 3.14-rc and earlier (in the case of the vt bugfix). Some
of these have been tested and reported by a number of people as the
tty bugfix was pretty commonly hit on some platforms.
All have been in linux-next for a while"
* tag 'tty-3.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
vt: Fix secure clear screen
serial: 8250: Support XR17V35x fraction divisor
n_tty: Fix stale echo output
serial: sirf: fix kernel panic caused by unpaired spinlock
serial: 8250_pci: unbreak last serial ports on NetMos 9865 cards
n_tty: Fix poll() when TIME_CHAR and MIN_CHAR == 0
serial: omap: fix rs485 probe on defered pinctrl
serial: 8250_dw: fix compilation warning when !CONFIG_PM_SLEEP
serial: omap-serial: Move info message to probe function
tty: Set correct tty name in 'active' sysfs attribute
tty: n_gsm: Fix for modems with brk in modem status control
drivers/tty/hvc: don't use module_init in non-modular hyp. console code
Linus Torvalds [Sat, 15 Feb 2014 00:14:11 +0000 (16:14 -0800)]
Merge tag 'staging-3.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
Pull staging driver fixes from Greg KH:
"Here are a number (lots, I know) of fixes for staging drivers to
resolve a bunch of reported issues.
The largest patches here is one revert of a patch that is in 3.14-rc1
to fix reported problems, and a sync of a usb host driver that
required some ARM patches to go in before it could be accepted (which
is why it missed -rc1)
All of these have been in linux-next for a while with no reported
issues"
* tag 'staging-3.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (56 commits)
staging/rtl8821ae: fix build, depends on MAC80211
iio: max1363: Use devm_regulator_get_optional for optional regulator
iio:accel:bma180: Use modifier instead of index in channel specification
iio: adis16400: Set timestamp as the last element in chan_spec
iio: ak8975: Fix calculation formula for convert micro tesla to gauss unit
staging:iio:ad799x fix typo in ad799x_events[]
iio: mxs-lradc: remove useless scale_available files
iio: mxs-lradc: fix buffer overflow
iio:magnetometer:mag3110: Fix output of decimal digits in show_int_plus_micros()
iio:magnetometer:mag3110: Report busy in _read_raw() / write_raw() when buffer is enabled
wlags49_h2: Fix overflow in wireless_set_essid()
xlr_net: Fix missing trivial allocation check
staging: r8188eu: overflow in rtw_p2p_get_go_device_address()
staging: r8188eu: array overflow in rtw_mp_ioctl_hdl()
staging: r8188eu: Fix typo in USB_DEVICE list
usbip/userspace/libsrc/names.c: memory leak
gpu: ion: dereferencing an ERR_PTR
staging: comedi: usbduxsigma: fix unaligned dereferences
staging: comedi: fix too early cleanup in comedi_auto_config()
staging: android: ion: dummy: fix an error code
...
Linus Torvalds [Sat, 15 Feb 2014 00:13:00 +0000 (16:13 -0800)]
Merge tag 'char-misc-3.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc fixes from Greg KH:
"Here are some small char/misc driver fixes, along with some
documentation updates, for 3.14-rc3. Nothing major, just a number of
fixes for reported issues"
* tag 'char-misc-3.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
Revert "misc: eeprom: sunxi: Add new compatibles"
Revert "ARM: sunxi: dt: Convert to the new SID compatibles"
misc: mic: fix possible signed underflow (undefined behavior) in userspace API
ARM: sunxi: dt: Convert to the new SID compatibles
misc: eeprom: sunxi: Add new compatibles
misc: genwqe: Fix potential memory leak when pinning memory
Documentation:Update Documentation/zh_CN/arm64/memory.txt
Documentation:Update Documentation/zh_CN/arm64/booting.txt
Documentation:Chinese translation of Documentation/arm64/tagged-pointers.txt
raw: set range for MAX_RAW_DEVS
raw: test against runtime value of max_raw_minors
Drivers: hv: vmbus: Don't timeout during the initial connection with host
Drivers: hv: vmbus: Specify the target CPU that should receive notification
VME: Correct read/write alignment algorithm
mei: don't unset read cb ptr on reset
mei: clear write cb from waiting list on reset
Josef Bacik [Fri, 14 Feb 2014 18:43:48 +0000 (13:43 -0500)]
Btrfs: unset DCACHE_DISCONNECTED when mounting default subvol
A user was running into errors from an NFS export of a subvolume that had a
default subvol set. When we mount a default subvol we will use d_obtain_alias()
to find an existing dentry for the subvolume in the case that the root subvol
has already been mounted, or a dummy one is allocated in the case that the root
subvol has not already been mounted. This allows us to connect the dentry later
on if we wander into the path. However if we don't ever wander into the path we
will keep DCACHE_DISCONNECTED set for a long time, which angers NFS. It doesn't
appear to cause any problems but it is annoying nonetheless, so simply unset
DCACHE_DISCONNECTED in the get_default_root case and switch btrfs_lookup() to
use d_materialise_unique() instead which will make everything play nicely
together and reconnect stuff if we wander into the defaul subvol path from a
different way. With this patch I'm no longer getting the NFS errors when
exporting a volume that has been mounted with a default subvol set. Thanks,
cc: bfields@fieldses.org
cc: ebiederm@xmission.com Signed-off-by: Josef Bacik <jbacik@fb.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Chris Mason <clm@fb.com>
projects / linux-beck.git / log