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path: root/kernel/rcutorture.c
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2007-10-17Make rcutorture RNG use temporal entropyPaul E. McKenney
Repost of http://lkml.org/lkml/2007/8/10/472 made available by request. The locking used by get_random_bytes() can conflict with the preempt_disable() and synchronize_sched() form of RCU. This patch changes rcutorture's RNG to gather entropy from the new cpu_clock() interface (relying on interrupts, preemption, daemons, and rcutorture's reader thread's rock-bottom scheduling priority to provide useful entropy), and also adds and EXPORT_SYMBOL_GPL() to make that interface available to GPLed kernel modules such as rcutorture. Passes several hours of rcutorture. [ego@in.ibm.com: Use raw_smp_processor_id() in rcu_random()] Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17Clean up duplicate includes in kernel/Jesper Juhl
This patch cleans up duplicate includes in kernel/ Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Satyam Sharma <ssatyam@cse.iitk.ac.in> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17Freezer: make kernel threads nonfreezable by defaultRafael J. Wysocki
Currently, the freezer treats all tasks as freezable, except for the kernel threads that explicitly set the PF_NOFREEZE flag for themselves. This approach is problematic, since it requires every kernel thread to either set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't care for the freezing of tasks at all. It seems better to only require the kernel threads that want to or need to be frozen to use some freezer-related code and to remove any freezer-related code from the other (nonfreezable) kernel threads, which is done in this patch. The patch causes all kernel threads to be nonfreezable by default (ie. to have PF_NOFREEZE set by default) and introduces the set_freezable() function that should be called by the freezable kernel threads in order to unset PF_NOFREEZE. It also makes all of the currently freezable kernel threads call set_freezable(), so it shouldn't cause any (intentional) change of behaviour to appear. Additionally, it updates documentation to describe the freezing of tasks more accurately. [akpm@linux-foundation.org: build fixes] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08rcutorture: Remove redundant assignment to cur_ops in for loopJosh Triplett
The for loop in rcutorture_init uses the condition cur_ops = torture_ops[i], cur_ops but then makes the same assignment to cur_ops inside the loop. Remove the redundant assignment inside the loop, and remove now-unnecessary braces. Signed-off-by: Josh Triplett <josh@kernel.org> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08rcutorture: style cleanup: avoid != NULL in boolean testsJosh Triplett
Signed-off-by: Josh Triplett <josh@kernel.org> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08rcutorture: Use ARRAY_SIZE macro when appropriateAhmed S. Darwish
Use ARRAY_SIZE macro already defined in kernel.h Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08rcutorture: Mark rcu_torture_init as __initJosh Triplett
The corresponding rcu_torture_cleanup cannot get marked as __exit, because rcu_torture_init uses it to clean up if init fails. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-06[PATCH] Publish rcutorture module parameters via sysfs, read-onlyJosh Triplett
rcutorture's module parameters currently use permissions of 0, so they don't show up in /sys/module/rcutorture/parameters. Change the permissions on all module parameters to world-readable (0444). rcutorture does all of its initialization and thread startup when loaded and relies on the parameters not changing during execution, so they should not permit writing. However, reading seems fine. Signed-off-by: Josh Triplett <josh@freedesktop.org> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-30[PATCH] rcu: rcutorture suspend fixIngo Molnar
Fix suspend hang: rcutorture threads need to be nofreeze. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] Add Sparse annotations to SRCU wrapper functions in rcutortureJosh Triplett
The SRCU wrapper functions srcu_torture_read_lock and srcu_torture_read_unlock in rcutorture intentionally change the SRCU context; annotate them accordingly, to avoid a warning. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] rcu: add sched torture type to rcutortureJosh Triplett
Implement torture testing for the "sched" variant of RCU, which uses preempt_disable, preempt_enable, and synchronize_sched. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] rcu: add rcu_bh_sync torture type to rcutortureJosh Triplett
Use the newly-generic synchronous deferred free function to implement torture testing for rcu_bh using synchronize_rcu_bh rather than the asynchronous call_rcu_bh. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] rcu: add rcu_sync torture type to rcutortureJosh Triplett
Use the newly-generic synchronous deferred free function to implement torture testing for RCU using synchronize_rcu rather than the asynchronous call_rcu. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] rcu: refactor srcu_torture_deferred_free to work for any implementationJosh Triplett
Make srcu_torture_deferred_free use cur_ops->sync() so it will work for any implementation. Move and rename it in preparation for use in the ops of other implementations. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] RCU: add fake writers to rcutortureJosh Triplett
rcutorture currently has one writer and an arbitrary number of readers. To better exercise some of the code paths in RCU implementations, add fake writer threads which call the synchronize function for the RCU variant in a loop, with a delay between calls to arrange for different numbers of writers running in parallel. [bunk@stusta.de: cleanup] Acked-by: Paul McKenney <paulmck@us.ibm.com> Cc: Dipkanar Sarma <dipankar@in.ibm.com> Signed-off-by: Josh Triplett <josh@freedesktop.org> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] rcu: Fix sign bug making rcu_random always return the same sequenceJosh Triplett
rcu_random uses a counter rrs_count to occasionally mix data from get_random_bytes into the state of its pseudorandom generator. However, the rrs_counter gets declared as an unsigned long, and rcu_random checks for --rrs_count < 0, so this code will never mix any real random data into the state, and will thus always return the same sequence of random numbers. Also, change the return value of rcu_random from long to unsigned long, to avoid potential issues caused by the use of the % operator, which can return negative values for negative left operands. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] rcu: Avoid kthread_stop on invalid pointer if rcutorture reader ↵Josh Triplett
startup fails rcu_torture_init kmallocs the array of reader threads, then creates each one with kthread_run, cleaning up with rcu_torture_cleanup if this fails. rcu_torture_cleanup calls kthread_stop on any non-NULL pointer in the array; however, any readers after the one that failed to start up will have invalid pointers, not null pointers. Avoid this by using kzalloc instead. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] rcu: Mention rcu_bh in description of rcutorture's torture_type ↵Josh Triplett
parameter The comment for rcutorture's torture_type parameter only lists the RCU variants rcu and srcu, but not rcu_bh; add rcu_bh to the list. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] rcu: Add MODULE_AUTHOR to rcutorture moduleJosh Triplett
Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] srcu-3: add SRCU operations to rcutorturePaul E. McKenney
Adds SRCU operations to rcutorture and updates rcutorture documentation. Also increases the stress imposed by the rcutorture test. [bunk@stusta.de: make needlessly global code static] Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Cc: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03rcutorture: Fix incorrect description of default for nreaders parameterJosh Triplett
The comment for the nreaders parameter of rcutorture gives the default as 4*ncpus, but the value actually defaults to 2*ncpus; fix the comment. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-09-29[PATCH] rcu: add lock annotations to rcu{,_bh}_torture_read_{lock,unlock}Josh Triplett
rcu_torture_read_lock and rcu_bh_torture_read_lock acquire locks without releasing them, and the matching functions rcu_torture_read_unlock and rcu_bh_torture_read_unlock get called with the corresponding locks held and release them. Add lock annotations to these four functions so that sparse can check callers for lock pairing, and so that sparse will not complain about these functions since they intentionally use locks in this manner. Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Paul McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27[PATCH] rcutorture: add call_rcu_bh() operationsPaul E. McKenney
Add operations for the call_rcu_bh() variant of RCU. Also add an rcu_batches_completed_bh() function, which is needed by rcutorture. Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27[PATCH] rcutorture: add ops vector and Classic RCU opsPaul E. McKenney
Add an ops vector to rcutorture, and add the ops for Classic RCU. Update the rcutorture documentation to reflect slight change to the dmesg formats. Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27[PATCH] rcutorture: catchup doc fixes for idle-hz testsPaul E. McKenney
This just catches the RCU torture documentation up with the recent fixes that test RCU for architectures that turn of the scheduling-clock interrupt for idle CPUs and the addition of a SUCCESS/FAILURE indication, fixing up an obsolete comment as well. Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28[PATCH] for_each_possible_cpu: fixes for generic partKAMEZAWA Hiroyuki
replaces for_each_cpu with for_each_possible_cpu(). Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-25[PATCH] Remove MODULE_PARMRusty Russell
MODULE_PARM was actually breaking: recent gcc version optimize them out as unused. It's time to replace the last users, which are generally in the most unloved drivers anyway. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-24[PATCH] rcutorture: tag success/failure line with module parametersPaul E. McKenney
A long-running rcutorture test can overflow dmesg, so that the line containing the module parameters is lost. Although it is usually possible to retrieve this information from the log files, it is much better to just tag it onto the final success/failure line so that it may be easily found. This patch does just that. Signed-off-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-31[PATCH] rcu_torture_lock deadlock fixIngo Molnar
rcu_torture_lock is used in a softirq-unsafe manner, but it is also taken by rcu_torture_cb(), which may execute in softirq-context, resulting in potential deadlocks. The fix is to acquire rcu_torture_lock in a softirq-safe manner. With this fix applied, the rcu-torture code passes validation. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08[PATCH] Extend RCU torture module to test tickless idle CPUSrivatsa Vaddagiri
This patch forces RCU torture threads off various CPUs in the system allowing them to become idle and go tickless. Meant to test support for such tickless idle CPU in RCU. Signed-off-by: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08[PATCH] rcu file: use atomic primitivesNick Piggin
Use atomic_inc_not_zero for rcu files instead of special case rcuref. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08[PATCH] kernel/: small cleanupsAdrian Bunk
This patch contains the following cleanups: - make needlessly global functions static - every file should include the headers containing the prototypes for it's global functions Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-12[PATCH] Fix bug in RCU torture testSrivatsa Vaddagiri
While doing some test of RCU torture module, I hit a OOPS in rcu_do_batch, which was trying to processes callback of a module that was just removed. This is because we weren't waiting long enough for all callbacks to fire. Signed-off-by: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-18[PATCH] add success/failure indication to RCU torture testPaul E. McKenney
One issue with the RCU torture test is that the current error flagging can be lost in dmesg. This patch adds a "SUCCESS"/"FAILURE" string to the line that flags the end of the test, where it can easily be seen with "dmesg | tail" at the end of the test. Also adds tests of architecture-specific memory barriers -- or, more likely, of the RCU torture test itself. Cc: <vatsa@in.ibm.com> Signed-off-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-13[PATCH] rcutorture: renice to low priorityIngo Molnar
Make the box usable for interactive work when running the RCU torture test, by renicing the RCU torture-test threads to +19 by default. Kthreads run at nice -5 by default. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] RCU torture-testing kernel modulePaul E. McKenney
This patch is a rewrite of the one submitted on October 1st, using modules (http://marc.theaimsgroup.com/?l=linux-kernel&m=112819093522998&w=2). This rewrite adds a tristate CONFIG_RCU_TORTURE_TEST, which enables an intense torture test of the RCU infratructure. This is needed due to the continued changes to the RCU infrastructure to accommodate dynamic ticks, CPU hotplug, realtime, and so on. Most of the code is in a separate file that is compiled only if the CONFIG variable is set. Documentation on how to run the test and interpret the output is also included. This code has been tested on i386 and ppc64, and an earlier version of the code has received extensive testing on a number of architectures as part of the PREEMPT_RT patchset. Signed-off-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>