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* ftrace: Add internal recursive checksSteven Rostedt2011-05-263-6/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Witold reported a reboot caused by the selftests of the dynamic function tracer. He sent me a config and I used ktest to do a config_bisect on it (as my config did not cause the crash). It pointed out that the problem config was CONFIG_PROVE_RCU. What happened was that if multiple callbacks are attached to the function tracer, we iterate a list of callbacks. Because the list is managed by synchronize_sched() and preempt_disable, the access to the pointers uses rcu_dereference_raw(). When PROVE_RCU is enabled, the rcu_dereference_raw() calls some debugging functions, which happen to be traced. The tracing of the debug function would then call rcu_dereference_raw() which would then call the debug function and then... well you get the idea. I first wrote two different patches to solve this bug. 1) add a __rcu_dereference_raw() that would not do any checks. 2) add notrace to the offending debug functions. Both of these patches worked. Talking with Paul McKenney on IRC, he suggested to add recursion detection instead. This seemed to be a better solution, so I decided to implement it. As the task_struct already has a trace_recursion to detect recursion in the ring buffer, and that has a very small number it allows, I decided to use that same variable to add flags that can detect the recursion inside the infrastructure of the function tracer. I plan to change it so that the task struct bit can be checked in mcount, but as that requires changes to all archs, I will hold that off to the next merge window. Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1306348063.1465.116.camel@gandalf.stny.rr.com Reported-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Add __print_symbolic_u64 to avoid warnings on 32bit machineliubo2011-05-261-0/+27
| | | | | | | | | | Filesystem, like Btrfs, has some "ULL" macros, and when these macros are passed to tracepoints'__print_symbolic(), there will be 64->32 truncate WARNINGS during compiling on 32bit box. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Link: http://lkml.kernel.org/r/4DACE6E0.7000507@cn.fujitsu.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace: Set ops->flag to enabled even on static function tracingSteven Rostedt2011-05-261-1/+5
| | | | | | | When dynamic ftrace is not configured, the ops->flags still needs to have its FTRACE_OPS_FL_ENABLED bit set in ftrace_startup(). Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Have event with function tracer check error returnSteven Rostedt2011-05-261-1/+6
| | | | | | | | The self tests for event tracer does not check if the function tracing was successfully activated. It needs to before it continues the tests, otherwise the wrong errors may be reported. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace: Have ftrace_startup() return failure codeSteven Rostedt2011-05-261-6/+8
| | | | | | | | | The register_ftrace_function() returns an error code on failure except if the call to ftrace_startup() fails. Add a error return to ftrace_startup() if it fails to start, allowing register_ftrace_funtion() to return a proper error value. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* jump_label: Check entries limit in __jump_label_updateJiri Olsa2011-05-261-5/+13
| | | | | | | | | | | | | | | | | | | When iterating the jump_label entries array (core or modules), the __jump_label_update function peeks over the last entry. The reason is that the end of the for loop depends on the key value of the processed entry. Thus when going through the last array entry, we will touch the memory behind the array limit. This bug probably will never be triggered, since most likely the memory behind the jump_label entries will be accesable and the entry->key will be different than the expected value. Signed-off-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Jason Baron <jbaron@redhat.com> Link: http://lkml.kernel.org/r/20110510104346.GC1899@jolsa.brq.redhat.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* watchdog: Fix non-standard prototype of get_softlockup_thresh()Ingo Molnar2011-05-241-7/+4
| | | | | | | | | | | | | | | | | | | | | | | This build warning slipped through: kernel/watchdog.c:102: warning: function declaration isn't a prototype As reported by Stephen Rothwell. Also address an unused variable warning that GCC 4.6.0 reports: we cannot do anything about failed watchdog ops during CPU hotplug (it's not serious enough to return an error from the notifier), so ignore them. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Mandeep Singh Baines <msb@chromium.org> Cc: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20110524134129.8da27016.sfr@canb.auug.org.au Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20110517071642.GF22305@elte.hu>
* Merge commit '559fa6e76b27' into perf/urgentIngo Molnar2011-05-231-4/+2
|\ | | | | | | | | | | | | Merge reason: this commit was queued up quite some time ago but was forgotten about. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * profile: Use vzalloc() rather than vmalloc() & memset()Jesper Juhl2010-10-311-4/+2
| | | | | | | | | | | | | | | | | | | | There's no reason to memset() manually when we have vzalloc(). Signed-off-by: Jesper Juhl <jj@chaosbits.net> Cc: Arjan van de Ven <arjan@infradead.org> Cc: William Irwin <wli@holomorphy.com> LKML-Reference: <alpine.LNX.2.00.1010302150310.1572@swampdragon.chaosbits.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | watchdog: Change the default timeout and configure nmi watchdog period based ↵Mandeep Singh Baines2011-05-231-4/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | on watchdog_thresh Before the conversion of the NMI watchdog to perf event, the watchdog timeout was 5 seconds. Now it is 60 seconds. For my particular application, netbooks, 5 seconds was a better timeout. With a short timeout, we catch faults earlier and are able to send back a panic. With a 60 second timeout, the user is unlikely to wait and will instead hit the power button, causing us to lose the panic info. This change configures the NMI period to watchdog_thresh and sets the softlockup_thresh to watchdog_thresh * 2. In addition, watchdog_thresh was reduced to 10 seconds as suggested by Ingo Molnar. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1306127423-3347-4-git-send-email-msb@chromium.org Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20110517071642.GF22305@elte.hu>
* | watchdog: Disable watchdog when thresh is zeroMandeep Singh Baines2011-05-232-20/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This restores the previous behavior of softlock_thresh. Currently, setting watchdog_thresh to zero causes the watchdog kthreads to consume a lot of CPU. In addition, the logic of proc_dowatchdog_thresh and proc_dowatchdog_enabled has been factored into proc_dowatchdog. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1306127423-3347-3-git-send-email-msb@chromium.org Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20110517071018.GE22305@elte.hu>
* | watchdog: Only disable/enable watchdog if neccessaryMandeep Singh Baines2011-05-231-8/+12
| | | | | | | | | | | | | | | | | | | | | | | | Don't take any action on an unsuccessful write to /proc. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1306127423-3347-2-git-send-email-msb@chromium.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | watchdog: Fix rounding bug in get_sample_period()Mandeep Singh Baines2011-05-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In get_sample_period(), softlockup_thresh is integer divided by 5 before the multiplication by NSEC_PER_SEC. This results in softlockup_thresh being rounded down to the nearest integer multiple of 5. For example, a softlockup_thresh of 4 rounds down to 0. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1306127423-3347-1-git-send-email-msb@chromium.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | extable, core_kernel_data(): Make sure all archs define _sdataSteven Rostedt2011-05-201-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A new utility function (core_kernel_data()) is used to determine if a passed in address is part of core kernel data or not. It may or may not return true for RO data, but this utility must work for RW data. Thus both _sdata and _edata must be defined and continuous, without .init sections that may later be freed and replaced by volatile memory (memory that can be freed). This utility function is used to determine if data is safe from ever being freed. Thus it should return true for all RW global data that is not in a module or has been allocated, or false otherwise. Also change core_kernel_data() back to the more precise _sdata condition and document the function. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Hirokazu Takata <takata@linux-m32r.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: linux-m68k@lists.linux-m68k.org Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Helge Deller <deller@gmx.de> Cc: JamesE.J.Bottomley <jejb@parisc-linux.org> Link: http://lkml.kernel.org/r/1305855298.1465.19.camel@gandalf.stny.rr.com Signed-off-by: Ingo Molnar <mingo@elte.hu> ---- arch/alpha/kernel/vmlinux.lds.S | 1 + arch/m32r/kernel/vmlinux.lds.S | 1 + arch/m68k/kernel/vmlinux-std.lds | 2 ++ arch/m68k/kernel/vmlinux-sun3.lds | 1 + arch/mips/kernel/vmlinux.lds.S | 1 + arch/parisc/kernel/vmlinux.lds.S | 3 +++ kernel/extable.c | 12 +++++++++++- 7 files changed, 20 insertions(+), 1 deletion(-)
* | Merge branch 'perf/core' into perf/urgentIngo Molnar2011-05-201-1/+1
|\ \ | | | | | | | | | | | | | | | | | | Merge reason: One pending commit was left in perf/core after Linus merged perf/core - continue v2.6.40 work in the perf/urgent reason. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | core_kernel_data(): Fix architectures that do not define _sdataIngo Molnar2011-05-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some architectures such as Alpha do not define _sdata but _data: kernel/built-in.o: In function `core_kernel_data': kernel/extable.c:77: undefined reference to `_sdata' So expand the scope of the data range to the text addresses too, this might be more correct anyway because this way we can cover readonly variables as well. Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/n/tip-i878c8a0e0g0ep4v7i6vxnhz@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'driver-core-next' of ↵Linus Torvalds2011-05-202-0/+12
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 * 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (44 commits) debugfs: Silence DEBUG_STRICT_USER_COPY_CHECKS=y warning sysfs: remove "last sysfs file:" line from the oops messages drivers/base/memory.c: fix warning due to "memory hotplug: Speed up add/remove when blocks are larger than PAGES_PER_SECTION" memory hotplug: Speed up add/remove when blocks are larger than PAGES_PER_SECTION SYSFS: Fix erroneous comments for sysfs_update_group(). driver core: remove the driver-model structures from the documentation driver core: Add the device driver-model structures to kerneldoc Translated Documentation/email-clients.txt RAW driver: Remove call to kobject_put(). reboot: disable usermodehelper to prevent fs access efivars: prevent oops on unload when efi is not enabled Allow setting of number of raw devices as a module parameter Introduce CONFIG_GOOGLE_FIRMWARE driver: Google Memory Console driver: Google EFI SMI x86: Better comments for get_bios_ebda() x86: get_bios_ebda_length() misc: fix ti-st build issues params.c: Use new strtobool function to process boolean inputs debugfs: move to new strtobool ... Fix up trivial conflicts in fs/debugfs/file.c due to the same patch being applied twice, and an unrelated cleanup nearby.
| * | | reboot: disable usermodehelper to prevent fs accessKay Sievers2011-05-071-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In case CONFIG_UEVENT_HELPER_PATH is not set to "", which it should be on every system, the kernel forks processes during shutdown, which try to access the rootfs, even when the binary does not exist. It causes exceptions and long delays in the disk driver, which gets read requests at the time it tries to shut down the disk. This patch disables all kernel-forked processes during reboot to allow a clean poweroff. Cc: Tejun Heo <htejun@gmail.com> Tested-By: Anton Guda <atu@dmeti.dp.ua> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * | | params.c: Use new strtobool function to process boolean inputsJonathan Cameron2011-04-261-10/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | No functional changes. Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * | | kernel/ksysfs.c: expose file_caps_enabled in sysfsLudwig Nussel2011-04-201-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A kernel booted with no_file_caps allows to install fscaps on a binary but doesn't actually honor the fscaps when running the binary. Userspace currently has no sane way to determine whether installing fscaps actually has any effect. Since parsing /proc/cmdline is fragile this patch exposes the current setting (1 or 0) via /sys/kernel/fscaps Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | | | Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2011-05-2011-400/+1333
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (78 commits) Revert "rcu: Decrease memory-barrier usage based on semi-formal proof" net,rcu: convert call_rcu(prl_entry_destroy_rcu) to kfree batman,rcu: convert call_rcu(softif_neigh_free_rcu) to kfree_rcu batman,rcu: convert call_rcu(neigh_node_free_rcu) to kfree() batman,rcu: convert call_rcu(gw_node_free_rcu) to kfree_rcu net,rcu: convert call_rcu(kfree_tid_tx) to kfree_rcu() net,rcu: convert call_rcu(xt_osf_finger_free_rcu) to kfree_rcu() net/mac80211,rcu: convert call_rcu(work_free_rcu) to kfree_rcu() net,rcu: convert call_rcu(wq_free_rcu) to kfree_rcu() net,rcu: convert call_rcu(phonet_device_rcu_free) to kfree_rcu() perf,rcu: convert call_rcu(swevent_hlist_release_rcu) to kfree_rcu() perf,rcu: convert call_rcu(free_ctx) to kfree_rcu() net,rcu: convert call_rcu(__nf_ct_ext_free_rcu) to kfree_rcu() net,rcu: convert call_rcu(net_generic_release) to kfree_rcu() net,rcu: convert call_rcu(netlbl_unlhsh_free_addr6) to kfree_rcu() net,rcu: convert call_rcu(netlbl_unlhsh_free_addr4) to kfree_rcu() security,rcu: convert call_rcu(sel_netif_free) to kfree_rcu() net,rcu: convert call_rcu(xps_dev_maps_release) to kfree_rcu() net,rcu: convert call_rcu(xps_map_release) to kfree_rcu() net,rcu: convert call_rcu(rps_map_release) to kfree_rcu() ...
| * | | | Revert "rcu: Decrease memory-barrier usage based on semi-formal proof"Paul E. McKenney2011-05-194-68/+90
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit e59fb3120becfb36b22ddb8bd27d065d3cdca499. This reversion was due to (extreme) boot-time slowdowns on SPARC seen by Yinghai Lu and on x86 by Ingo . This is a non-trivial reversion due to intervening commits. Conflicts: Documentation/RCU/trace.txt kernel/rcutree.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | perf,rcu: convert call_rcu(swevent_hlist_release_rcu) to kfree_rcu()Lai Jiangshan2011-05-081-9/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu callback swevent_hlist_release_rcu() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(swevent_hlist_release_rcu). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | perf,rcu: convert call_rcu(free_ctx) to kfree_rcu()Lai Jiangshan2011-05-081-9/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu callback free_ctx() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(free_ctx). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | cgroup,rcu: convert call_rcu(__free_css_id_cb) to kfree_rcu()Lai Jiangshan2011-05-081-9/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu callback __free_css_id_cb() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(__free_css_id_cb). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | cgroup,rcu: convert call_rcu(free_cgroup_rcu) to kfree_rcu()Lai Jiangshan2011-05-081-8/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu callback free_cgroup_rcu() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(free_cgroup_rcu). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | cgroup,rcu: convert call_rcu(free_css_set_rcu) to kfree_rcu()Lai Jiangshan2011-05-081-7/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu callback free_css_set_rcu() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(free_css_set_rcu). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: permit rcu_read_unlock() to be called while holding runqueue locksPaul E. McKenney2011-05-083-79/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid calling into the scheduler while holding core RCU locks. This allows rcu_read_unlock() to be called while holding the runqueue locks, but only as long as there was no chance of the RCU read-side critical section having been preempted. (Otherwise, if RCU priority boosting is enabled, rcu_read_unlock() might call into the scheduler in order to unboost itself, which might allows self-deadlock on the runqueue locks within the scheduler.) Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | | | rcu: provide rcu_virt_note_context_switch() function.Gleb Natapov2011-05-061-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Provide rcu_virt_note_context_switch() for vitalization use to note quiescent state during guest entry. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | | | rcu: get rid of signed overflow in check_cpu_stall()Paul E. McKenney2011-05-061-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed integer overflow is undefined by the C standard, so move calculations to unsigned. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | | | rcu: optimize rcutinyEric Dumazet2011-05-061-22/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | rcu_sched_qs() currently calls local_irq_save()/local_irq_restore() up to three times. Remove irq masking from rcu_qsctr_help() / invoke_rcu_kthread() and do it once in rcu_sched_qs() / rcu_bh_qs() This generates smaller code as well. text data bss dec hex filename 2314 156 24 2494 9be kernel/rcutiny.old.o 2250 156 24 2430 97e kernel/rcutiny.new.o Fix an outdated comment for rcu_qsctr_help() Move invoke_rcu_kthread() definition before its use. Signed-off-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>
| * | | | rcu: prevent call_rcu() from diving into rcu core if irqs disabledPaul E. McKenney2011-05-061-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit marks a first step towards making call_rcu() have real-time behavior. If irqs are disabled, don't dive into the RCU core. Later on, this new early exit will wake up the per-CPU kthread, which first must be modified to handle the cases involving callback storms. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: further lower priority in rcu_yield()Paul E. McKenney2011-05-061-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Although rcu_yield() dropped from real-time to normal priority, there is always the possibility that the competing tasks have been niced. So nice to 19 in rcu_yield() to help ensure that other tasks have a better chance of running. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: introduce kfree_rcu()Lai Jiangshan2011-05-062-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many rcu callbacks functions just call kfree() on the base structure. These functions are trivial, but their size adds up, and furthermore when they are used in a kernel module, that module must invoke the high-latency rcu_barrier() function at module-unload time. The kfree_rcu() function introduced by this commit addresses this issue. Rather than encoding a function address in the embedded rcu_head structure, kfree_rcu() instead encodes the offset of the rcu_head structure within the base structure. Because the functions are not allowed in the low-order 4096 bytes of kernel virtual memory, offsets up to 4095 bytes can be accommodated. If the offset is larger than 4095 bytes, a compile-time error will be generated in __kfree_rcu(). If this error is triggered, you can either fall back to use of call_rcu() or rearrange the structure to position the rcu_head structure into the first 4096 bytes. Note that the allowable offset might decrease in the future, for example, to allow something like kmem_cache_free_rcu(). The new kfree_rcu() function can replace code as follows: call_rcu(&p->rcu, simple_kfree_callback); where "simple_kfree_callback()" might be defined as follows: void simple_kfree_callback(struct rcu_head *p) { struct foo *q = container_of(p, struct foo, rcu); kfree(q); } with the following: kfree_rcu(&p->rcu, rcu); Note that the "rcu" is the name of a field in the structure being freed. The reason for using this rather than passing in a pointer to the base structure is that the above approach allows better type checking. This commit is based on earlier work by Lai Jiangshan and Manfred Spraul: Lai's V1 patch: http://lkml.org/lkml/2008/9/18/1 Manfred's patch: http://lkml.org/lkml/2009/1/2/115 Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: David Howells <dhowells@redhat.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: fix spellingPaul E. McKenney2011-05-063-37/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The "preemptible" spelling is preferable. May as well fix it. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: call __rcu_read_unlock() in exit_rcu for tree RCULai Jiangshan2011-05-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using __rcu_read_lock() in place of rcu_read_lock() leaves any debug state as it really should be, namely with the lock still held. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: Converge TINY_RCU expedited and normal boostingPaul E. McKenney2011-05-061-74/+89
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This applies a trick from TREE_RCU boosting to TINY_RCU, eliminating code and adding comments. The key point is that it is possible for the booster thread itself to work out whether there is a normal or expedited boost required based solely on local information. There is therefore no need for boost initiation to know or care what type of boosting is required. In addition, when boosting is complete for a given grace period, then by definition there cannot be any more boosting for that grace period. This allows eliminating yet more state and statistics. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: remove useless ->boosted_this_gp fieldPaul E. McKenney2011-05-061-31/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ->boosted_this_gp field is a holdover from an earlier design that was to carry out multiple boost operations in parallel. It is not required by the current design, which boosts one task at a time. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | | | rcu: code cleanups in TINY_RCU priority boosting.Paul E. McKenney2011-05-061-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extraneous semicolon, bad comment, and fold INIT_LIST_HEAD() into list_del() to get list_del_init(). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: Switch to this_cpu() primitivesPaul E. McKenney2011-05-061-7/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This removes a couple of lines from invoke_rcu_cpu_kthread(), improving readability. Reported-by: Christoph Lameter <cl@linux.com> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: Use WARN_ON_ONCE for DEBUG_OBJECTS_RCU_HEAD warningsPaul E. McKenney2011-05-061-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid additional multiple-warning confusion in memory-corruption scenarios. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: mark rcutorture boosting callback as being on-stackPaul E. McKenney2011-05-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The CONFIG_DEBUG_OBJECTS_RCU_HEAD facility requires that on-stack RCU callbacks be flagged explicitly to debug-objects using the init_rcu_head_on_stack() and destroy_rcu_head_on_stack() functions. This commit applies those functions to the rcutorture code that tests RCU priority boosting. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: Enable DEBUG_OBJECTS_RCU_HEAD from !PREEMPTMathieu Desnoyers2011-05-061-5/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The prohibition of DEBUG_OBJECTS_RCU_HEAD from !PREEMPT was due to the fixup actions. So just produce a warning from !PREEMPT. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: Add forward-progress diagnostic for per-CPU kthreadsPaul E. McKenney2011-05-062-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Increment a per-CPU counter on each pass through rcu_cpu_kthread()'s service loop, and add it to the rcudata trace output. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: add grace-period age and more kthread state to tracingPaul E. McKenney2011-05-063-10/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds the age in jiffies of the current grace period along with the duration in jiffies of the longest grace period since boot to the rcu/rcugp debugfs file. It also adds an additional "O" state to kthread tracing to differentiate between the kthread waiting due to having nothing to do on the one hand and waiting due to being on the wrong CPU on the other hand. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | | | rcu: fix tracing bug thinko on boost-balk attributionPaul E. McKenney2011-05-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu_initiate_boost_trace() function mis-attributed refusals to initiate RCU priority boosting that were in fact due to its not yet being time to boost. This patch fixes the faulty comparison. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | | | rcu: make rcutorture version numbers available through debugfsPaul E. McKenney2011-05-063-3/+70
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is not possible to accurately correlate rcutorture output with that of debugfs. This patch therefore adds a debugfs file that prints out the rcutorture version number, permitting easy correlation. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: add tracing for RCU's kthread run states.Paul E. McKenney2011-05-064-4/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add tracing to help debugging situations when RCU's kthreads are not running but are supposed to be. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: add callback-queue information to rcudata outputPaul E. McKenney2011-05-061-2/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds an indication of the state of the callback queue using a string of four characters following the "ql=" integer queue length. The first character is "N" if there are callbacks that have been queued that are not yet ready to be handled by the next grace period, or "." otherwise. The second character is "R" if there are callbacks queued that are ready to be handled by the next grace period, or "." otherwise. The third character is "W" if there are callbacks waiting for the current grace period, or "." otherwise. Finally, the fourth character is "D" if there are callbacks that have been handled by a prior grace period and are waiting to be invoked, or ".". Note that callbacks that are in the process of being invoked are not shown. These callbacks would have been removed from the rcu_data structure's list by rcu_do_batch() prior to being executed. (These callbacks are also not reflected in the "ql=" total, FWIW.) Also, document the new callback-queue trace information. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | | | rcu: Add boosting to TREE_PREEMPT_RCU tracingPaul E. McKenney2011-05-063-4/+125
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Includes total number of tasks boosted, number boosted on behalf of each of normal and expedited grace periods, and statistics on attempts to initiate boosting that failed for various reasons. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-06 16:24:49 +0100