1. 29 5月, 2013 1 次提交
  2. 19 4月, 2013 1 次提交
    • F
      nohz: Ensure full dynticks CPUs are RCU nocbs · d1e43fa5
      Frederic Weisbecker 提交于
      We need full dynticks CPU to also be RCU nocb so
      that we don't have to keep the tick to handle RCU
      callbacks.
      
      Make sure the range passed to nohz_full= boot
      parameter is a subset of rcu_nocbs=
      
      The CPUs that fail to meet this requirement will be
      excluded from the nohz_full range. This is checked
      early in boot time, before any CPU has the opportunity
      to stop its tick.
      Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
      Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Chris Metcalf <cmetcalf@tilera.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Geoff Levand <geoff@infradead.org>
      Cc: Gilad Ben Yossef <gilad@benyossef.com>
      Cc: Hakan Akkan <hakanakkan@gmail.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Kevin Hilman <khilman@linaro.org>
      Cc: Li Zhong <zhong@linux.vnet.ibm.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      d1e43fa5
  3. 26 3月, 2013 1 次提交
  4. 27 1月, 2013 1 次提交
  5. 09 1月, 2013 1 次提交
    • P
      rcu: Reduce rcutorture tracing · 52494535
      Paul E. McKenney 提交于
      Currently, rcutorture traces every read-side access.  This can be
      problematic because even a two-minute rcutorture run on a two-CPU system
      can generate 28,853,363 reads.  Normally, only a failing read is of
      interest, so this commit traces adjusts rcutorture's tracing to only
      trace failing reads.  The resulting event tracing records the time
      and the ->completed value captured at the beginning of the RCU read-side
      critical section, allowing correlation with other event-tracing messages.
      Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      [ paulmck: Add fix to build problem located by Randy Dunlap based on
        diagnosis by Steven Rostedt. ]
      52494535
  6. 01 12月, 2012 1 次提交
    • F
      context_tracking: New context tracking susbsystem · 91d1aa43
      Frederic Weisbecker 提交于
      Create a new subsystem that probes on kernel boundaries
      to keep track of the transitions between level contexts
      with two basic initial contexts: user or kernel.
      
      This is an abstraction of some RCU code that use such tracking
      to implement its userspace extended quiescent state.
      
      We need to pull this up from RCU into this new level of indirection
      because this tracking is also going to be used to implement an "on
      demand" generic virtual cputime accounting. A necessary step to
      shutdown the tick while still accounting the cputime.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Li Zhong <zhong@linux.vnet.ibm.com>
      Cc: Gilad Ben-Yossef <gilad@benyossef.com>
      Reviewed-by: NSteven Rostedt <rostedt@goodmis.org>
      [ paulmck: fix whitespace error and email address. ]
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      91d1aa43
  7. 14 11月, 2012 1 次提交
  8. 24 10月, 2012 1 次提交
  9. 26 9月, 2012 4 次提交
    • F
      rcu: Switch task's syscall hooks on context switch · 04e7e951
      Frederic Weisbecker 提交于
      Clear the syscalls hook of a task when it's scheduled out so that if
      the task migrates, it doesn't run the syscall slow path on a CPU
      that might not need it.
      
      Also set the syscalls hook on the next task if needed.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Alessio Igor Bogani <abogani@kernel.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Avi Kivity <avi@redhat.com>
      Cc: Chris Metcalf <cmetcalf@tilera.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Geoff Levand <geoff@infradead.org>
      Cc: Gilad Ben Yossef <gilad@benyossef.com>
      Cc: Hakan Akkan <hakanakkan@gmail.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Kevin Hilman <khilman@ti.com>
      Cc: Max Krasnyansky <maxk@qualcomm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephen Hemminger <shemminger@vyatta.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      04e7e951
    • F
      rcu: Settle config for userspace extended quiescent state · 2b1d5024
      Frederic Weisbecker 提交于
      Create a new config option under the RCU menu that put
      CPUs under RCU extended quiescent state (as in dynticks
      idle mode) when they run in userspace. This require
      some contribution from architectures to hook into kernel
      and userspace boundaries.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Alessio Igor Bogani <abogani@kernel.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Avi Kivity <avi@redhat.com>
      Cc: Chris Metcalf <cmetcalf@tilera.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Geoff Levand <geoff@infradead.org>
      Cc: Gilad Ben Yossef <gilad@benyossef.com>
      Cc: Hakan Akkan <hakanakkan@gmail.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Kevin Hilman <khilman@ti.com>
      Cc: Max Krasnyansky <maxk@qualcomm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephen Hemminger <shemminger@vyatta.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      2b1d5024
    • F
      rcu: New rcu_user_enter_after_irq() and rcu_user_exit_after_irq() APIs · 19dd1591
      Frederic Weisbecker 提交于
      In some cases, it is necessary to enter or exit userspace-RCU-idle mode
      from an interrupt handler, for example, if some other CPU sends this
      CPU a resched IPI.  In this case, the current CPU would enter the IPI
      handler in userspace-RCU-idle mode, but would need to exit the IPI handler
      after having exited that mode.
      
      To allow this to work, this commit adds two new APIs to TREE_RCU:
      
      - rcu_user_enter_after_irq(). This must be called from an interrupt between
      rcu_irq_enter() and rcu_irq_exit().  After the irq calls rcu_irq_exit(),
      the irq handler will return into an RCU extended quiescent state.
      In theory, this interrupt is never a nested interrupt, but in practice
      it might interrupt softirq, which looks to RCU like a nested interrupt.
      
      - rcu_user_exit_after_irq(). This must be called from a non-nesting
      interrupt, interrupting an RCU extended quiescent state, also
      between rcu_irq_enter() and rcu_irq_exit(). After the irq calls
      rcu_irq_exit(), the irq handler will return in an RCU non-quiescent
      state.
      
      [ Combined with "Allow calls to rcu_exit_user_irq from nesting irqs." ]
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      19dd1591
    • F
      rcu: New rcu_user_enter() and rcu_user_exit() APIs · adf5091e
      Frederic Weisbecker 提交于
      RCU currently insists that only idle tasks can enter RCU idle mode, which
      prohibits an adaptive tickless kernel (AKA nohz cpusets), which in turn
      would mean that usermode execution would always take scheduling-clock
      interrupts, even when there is only one task runnable on the CPU in
      question.
      
      This commit therefore adds rcu_user_enter() and rcu_user_exit(), which
      allow non-idle tasks to enter RCU idle mode.  These are quite similar
      to rcu_idle_enter() and rcu_idle_exit(), respectively, except that they
      omit the idle-task checks.
      
      [ Updated to use "user" flag rather than separate check functions. ]
      
      [ paulmck: Updated to drop exports of new functions based on Josh's patch
        getting rid of the need for them. ]
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Alessio Igor Bogani <abogani@kernel.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Avi Kivity <avi@redhat.com>
      Cc: Chris Metcalf <cmetcalf@tilera.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
      Cc: Geoff Levand <geoff@infradead.org>
      Cc: Gilad Ben Yossef <gilad@benyossef.com>
      Cc: Hakan Akkan <hakanakkan@gmail.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Kevin Hilman <khilman@ti.com>
      Cc: Max Krasnyansky <maxk@qualcomm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephen Hemminger <shemminger@vyatta.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      adf5091e
  10. 23 9月, 2012 1 次提交
  11. 06 7月, 2012 1 次提交
  12. 03 7月, 2012 8 次提交
  13. 03 5月, 2012 2 次提交
  14. 25 4月, 2012 1 次提交
  15. 24 3月, 2012 1 次提交
  16. 05 3月, 2012 1 次提交
    • P
      BUG: headers with BUG/BUG_ON etc. need linux/bug.h · 187f1882
      Paul Gortmaker 提交于
      If a header file is making use of BUG, BUG_ON, BUILD_BUG_ON, or any
      other BUG variant in a static inline (i.e. not in a #define) then
      that header really should be including <linux/bug.h> and not just
      expecting it to be implicitly present.
      
      We can make this change risk-free, since if the files using these
      headers didn't have exposure to linux/bug.h already, they would have
      been causing compile failures/warnings.
      Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      187f1882
  17. 22 2月, 2012 6 次提交
  18. 12 12月, 2011 6 次提交
    • P
      rcu: Document same-context read-side constraints · 3842a083
      Paul E. McKenney 提交于
      The intent is that a given RCU read-side critical section be confined
      to a single context.  For example, it is illegal to invoke rcu_read_lock()
      in an exception handler and then invoke rcu_read_unlock() from the
      context of the task that received the exception.
      Suggested-by: NPeter Zijlstra <peterz@infradead.org>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      3842a083
    • P
      rcu: Remove one layer of abstraction from PROVE_RCU checking · d8ab29f8
      Paul E. McKenney 提交于
      Simplify things a bit by substituting the definitions of the single-line
      rcu_read_acquire(), rcu_read_release(), rcu_read_acquire_bh(),
      rcu_read_release_bh(), rcu_read_acquire_sched(), and
      rcu_read_release_sched() functions at their call points.
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      d8ab29f8
    • F
      rcu: Warn when rcu_read_lock() is used in extended quiescent state · 00f49e57
      Frederic Weisbecker 提交于
      We are currently able to detect uses of rcu_dereference_check() inside
      extended quiescent states (such as the RCU-free window in idle).
      But rcu_read_lock() and friends can be used without rcu_dereference(),
      so that the earlier commit checking for use of rcu_dereference() and
      friends while in RCU idle mode miss some error conditions.  This commit
      therefore adds extended quiescent state checking to rcu_read_lock() and
      friends.
      
      Uses of RCU from within RCU-idle mode are totally ignored by
      RCU, hence the importance of these checks.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      00f49e57
    • F
      rcu: Detect illegal rcu dereference in extended quiescent state · e6b80a3b
      Frederic Weisbecker 提交于
      Report that none of the rcu read lock maps are held while in an RCU
      extended quiescent state (the section between rcu_idle_enter()
      and rcu_idle_exit()). This helps detect any use of rcu_dereference()
      and friends from within the section in idle where RCU is not allowed.
      
      This way we can guarantee an extended quiescent window where the CPU
      can be put in dyntick idle mode or can simply aoid to be part of any
      global grace period completion while in the idle loop.
      
      Uses of RCU from such mode are totally ignored by RCU, hence the
      importance of these checks.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      e6b80a3b
    • P
      rcu: Add failure tracing to rcutorture · 91afaf30
      Paul E. McKenney 提交于
      Trace the rcutorture RCU accesses and dump the trace buffer when the
      first failure is detected.
      Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      91afaf30
    • P
      rcu: Track idleness independent of idle tasks · 9b2e4f18
      Paul E. McKenney 提交于
      Earlier versions of RCU used the scheduling-clock tick to detect idleness
      by checking for the idle task, but handled idleness differently for
      CONFIG_NO_HZ=y.  But there are now a number of uses of RCU read-side
      critical sections in the idle task, for example, for tracing.  A more
      fine-grained detection of idleness is therefore required.
      
      This commit presses the old dyntick-idle code into full-time service,
      so that rcu_idle_enter(), previously known as rcu_enter_nohz(), is
      always invoked at the beginning of an idle loop iteration.  Similarly,
      rcu_idle_exit(), previously known as rcu_exit_nohz(), is always invoked
      at the end of an idle-loop iteration.  This allows the idle task to
      use RCU everywhere except between consecutive rcu_idle_enter() and
      rcu_idle_exit() calls, in turn allowing architecture maintainers to
      specify exactly where in the idle loop that RCU may be used.
      
      Because some of the userspace upcall uses can result in what looks
      to RCU like half of an interrupt, it is not possible to expect that
      the irq_enter() and irq_exit() hooks will give exact counts.  This
      patch therefore expands the ->dynticks_nesting counter to 64 bits
      and uses two separate bitfields to count process/idle transitions
      and interrupt entry/exit transitions.  It is presumed that userspace
      upcalls do not happen in the idle loop or from usermode execution
      (though usermode might do a system call that results in an upcall).
      The counter is hard-reset on each process/idle transition, which
      avoids the interrupt entry/exit error from accumulating.  Overflow
      is avoided by the 64-bitness of the ->dyntick_nesting counter.
      
      This commit also adds warnings if a non-idle task asks RCU to enter
      idle state (and these checks will need some adjustment before applying
      Frederic's OS-jitter patches (http://lkml.org/lkml/2011/10/7/246).
      In addition, validation of ->dynticks and ->dynticks_nesting is added.
      Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      9b2e4f18
  19. 29 9月, 2011 1 次提交