1. 26 10月, 2009 3 次提交
    • P
      rcu: Add synchronize_srcu_expedited() to the rcutorture test suite · 804bb837
      Paul E. McKenney 提交于
      Adds the "srcu_expedited" torture type, and also renames
      sched_ops_sync to sched_sync_ops for consistency while we are in
      this file.
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Acked-by: NJosh Triplett <josh@joshtriplett.org>
      Reviewed-by: NLai Jiangshan <laijs@cn.fujitsu.com>
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: dhowells@redhat.com
      Cc: avi@redhat.com
      Cc: mtosatti@redhat.com
      LKML-Reference: <12565226353636-git-send-email->
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      804bb837
    • P
      rcu: Add synchronize_srcu_expedited() · 0cd397d3
      Paul E. McKenney 提交于
      This patch creates a synchronize_srcu_expedited() that uses
      synchronize_sched_expedited() where synchronize_srcu()
      uses synchronize_sched().  The synchronize_srcu() and
      synchronize_srcu_expedited() functions become one-liners that
      pass synchronize_sched() or synchronize_sched_expedited(),
      repectively, to a new __synchronize_srcu() function.
      
      While in the file, move the EXPORT_SYMBOL_GPL()s to immediately
      follow the corresponding functions.
      Requested-by: NAvi Kivity <avi@redhat.com>
      Tested-by: NMarcelo Tosatti <mtosatti@redhat.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Acked-by: NJosh Triplett <josh@joshtriplett.org>
      Reviewed-by: NLai Jiangshan <laijs@cn.fujitsu.com>
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: dhowells@redhat.com
      Cc: avi@redhat.com
      LKML-Reference: <12565226354038-git-send-email->
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      0cd397d3
    • P
      rcu: "Tiny RCU", The Bloatwatch Edition · 9b1d82fa
      Paul E. McKenney 提交于
      This patch is a version of RCU designed for !SMP provided for a
      small-footprint RCU implementation.  In particular, the
      implementation of synchronize_rcu() is extremely lightweight and
      high performance. It passes rcutorture testing in each of the
      four relevant configurations (combinations of NO_HZ and PREEMPT)
      on x86.  This saves about 1K bytes compared to old Classic RCU
      (which is no longer in mainline), and more than three kilobytes
      compared to Hierarchical RCU (updated to 2.6.30):
      
      	CONFIG_TREE_RCU:
      
      	   text	   data	    bss	    dec	    filename
      	    183       4       0     187     kernel/rcupdate.o
      	   2783     520      36    3339     kernel/rcutree.o
      				   3526 Total (vs 4565 for v7)
      
      	CONFIG_TREE_PREEMPT_RCU:
      
      	   text	   data	    bss	    dec	    filename
      	    263       4       0     267     kernel/rcupdate.o
      	   4594     776      52    5422     kernel/rcutree.o
      	   			   5689 Total (6155 for v7)
      
      	CONFIG_TINY_RCU:
      
      	   text	   data	    bss	    dec	    filename
      	     96       4       0     100     kernel/rcupdate.o
      	    734      24       0     758     kernel/rcutiny.o
      	    			    858 Total (vs 848 for v7)
      
      The above is for x86.  Your mileage may vary on other platforms.
      Further compression is possible, but is being procrastinated.
      
      Changes from v7 (http://lkml.org/lkml/2009/10/9/388)
      
      o	Apply Lai Jiangshan's review comments (aside from
      might_sleep() 	in synchronize_sched(), which is covered by SMP builds).
      
      o	Fix up expedited primitives.
      
      Changes from v6 (http://lkml.org/lkml/2009/9/23/293).
      
      o	Forward ported to put it into the 2.6.33 stream.
      
      o	Added lockdep support.
      
      o	Make lightweight rcu_barrier.
      
      Changes from v5 (http://lkml.org/lkml/2009/6/23/12).
      
      o	Ported to latest pre-2.6.32 merge window kernel.
      
      	- Renamed rcu_qsctr_inc() to rcu_sched_qs().
      	- Renamed rcu_bh_qsctr_inc() to rcu_bh_qs().
      	- Provided trivial rcu_cpu_notify().
      	- Provided trivial exit_rcu().
      	- Provided trivial rcu_needs_cpu().
      	- Fixed up the rcu_*_enter/exit() functions in linux/hardirq.h.
      
      o	Removed the dependence on EMBEDDED, with a view to making
      	TINY_RCU default for !SMP at some time in the future.
      
      o	Added (trivial) support for expedited grace periods.
      
      Changes from v4 (http://lkml.org/lkml/2009/5/2/91) include:
      
      o	Squeeze the size down a bit further by removing the
      	->completed field from struct rcu_ctrlblk.
      
      o	This permits synchronize_rcu() to become the empty function.
      	Previous concerns about rcutorture were unfounded, as
      	rcutorture correctly handles a constant value from
      	rcu_batches_completed() and rcu_batches_completed_bh().
      
      Changes from v3 (http://lkml.org/lkml/2009/3/29/221) include:
      
      o	Changed rcu_batches_completed(), rcu_batches_completed_bh()
      	rcu_enter_nohz(), rcu_exit_nohz(), rcu_nmi_enter(), and
      	rcu_nmi_exit(), to be static inlines, as suggested by David
      	Howells.  Doing this saves about 100 bytes from rcutiny.o.
      	(The numbers between v3 and this v4 of the patch are not directly
      	comparable, since they are against different versions of Linux.)
      
      Changes from v2 (http://lkml.org/lkml/2009/2/3/333) include:
      
      o	Fix whitespace issues.
      
      o	Change short-circuit "||" operator to instead be "+" in order
      to 	fix performance bug noted by "kraai" on LWN.
      
      		(http://lwn.net/Articles/324348/)
      
      Changes from v1 (http://lkml.org/lkml/2009/1/13/440) include:
      
      o	This version depends on EMBEDDED as well as !SMP, as suggested
      	by Ingo.
      
      o	Updated rcu_needs_cpu() to unconditionally return zero,
      	permitting the CPU to enter dynticks-idle mode at any time.
      	This works because callbacks can be invoked upon entry to
      	dynticks-idle mode.
      
      o	Paul is now OK with this being included, based on a poll at
      the 	Kernel Miniconf at linux.conf.au, where about ten people said
      	that they cared about saving 900 bytes on single-CPU systems.
      
      o	Applies to both mainline and tip/core/rcu.
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Acked-by: NDavid Howells <dhowells@redhat.com>
      Acked-by: NJosh Triplett <josh@joshtriplett.org>
      Reviewed-by: NLai Jiangshan <laijs@cn.fujitsu.com>
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: avi@redhat.com
      Cc: mtosatti@redhat.com
      LKML-Reference: <12565226351355-git-send-email->
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      9b1d82fa
  2. 15 10月, 2009 6 次提交
    • P
      rcu: Update trace.txt documentation for blocked-tasks lists · 0edf1a68
      Paul E. McKenney 提交于
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: laijs@cn.fujitsu.com
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: josh@joshtriplett.org
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: dhowells@redhat.com
      Cc: npiggin@suse.de
      Cc: jens.axboe@oracle.com
      LKML-Reference: <12555405592804-git-send-email->
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      0edf1a68
    • P
      rcu: Update trace.txt documentation to reflect recent changes · bd58b430
      Paul E. McKenney 提交于
      o	Remove the CONFIG_PREEMPT_RCU documentation since this
      	config option has now been removed.
      
      o	Change the now-incorrect references to "rcu" labels to
      	instead be "rcu_sched".
      
      o	Add notes stating that CONFIG_TREE_PREEMPT_RCU kernels will
      	have additional "rcu_preempt" output.
      
      o	Note the new "oqlen" field in the rcuhier output (for
      	RCU callbacks orphaned by an offlined CPU).
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: laijs@cn.fujitsu.com
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: josh@joshtriplett.org
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: dhowells@redhat.com
      Cc: npiggin@suse.de
      Cc: jens.axboe@oracle.com
      LKML-Reference: <1255540559799-git-send-email->
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      bd58b430
    • P
      rcu: Add rnp->blocked_tasks to tracing · 3397e040
      Paul E. McKenney 提交于
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: laijs@cn.fujitsu.com
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: dhowells@redhat.com
      Cc: npiggin@suse.de
      Cc: jens.axboe@oracle.com
      Cc: Josh Triplett <josh@joshtriplett.org>
      LKML-Reference: <20091014233638.GE6763@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
       kernel/rcutree_trace.c |    8 ++++++--
       1 file changed, 6 insertions(+), 2 deletions(-)
      3397e040
    • P
      rcu: Stopgap fix for synchronize_rcu_expedited() for TREE_PREEMPT_RCU · 019129d5
      Paul E. McKenney 提交于
      For the short term, map synchronize_rcu_expedited() to
      synchronize_rcu() for TREE_PREEMPT_RCU and to
      synchronize_sched_expedited() for TREE_RCU.
      
      Longer term, there needs to be a real expedited grace period for
      TREE_PREEMPT_RCU, but candidate patches to date are considerably
      more complex and intrusive.
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: laijs@cn.fujitsu.com
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: josh@joshtriplett.org
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: dhowells@redhat.com
      Cc: npiggin@suse.de
      Cc: jens.axboe@oracle.com
      LKML-Reference: <12555405592331-git-send-email->
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      019129d5
    • P
      rcu: Prevent RCU IPI storms in presence of high call_rcu() load · 37c72e56
      Paul E. McKenney 提交于
      As the number of callbacks on a given CPU rises, invoke
      force_quiescent_state() only every blimit number of callbacks
      (defaults to 10,000), and even then only if no other CPU has
      invoked force_quiescent_state() in the meantime.
      
      This should fix the performance regression reported by Nick.
      Reported-by: NNick Piggin <npiggin@suse.de>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: laijs@cn.fujitsu.com
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: josh@joshtriplett.org
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: dhowells@redhat.com
      Cc: jens.axboe@oracle.com
      LKML-Reference: <12555405592133-git-send-email->
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      37c72e56
    • D
      futex: Check for NULL keys in match_futex · 2bc87203
      Darren Hart 提交于
      If userspace tries to perform a requeue_pi on a non-requeue_pi waiter,
      it will find the futex_q->requeue_pi_key to be NULL and OOPS.
      
      Check for NULL in match_futex() instead of doing explicit NULL pointer
      checks on all call sites.  While match_futex(NULL, NULL) returning
      false is a little odd, it's still correct as we expect valid key
      references.
      Signed-off-by: NDarren Hart <dvhltc@us.ibm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      CC: Eric Dumazet <eric.dumazet@gmail.com>
      CC: Dinakar Guniguntala <dino@in.ibm.com>
      CC: John Stultz <johnstul@us.ibm.com>
      Cc: stable@kernel.org
      LKML-Reference: <4AD60687.10306@us.ibm.com>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      2bc87203
  3. 14 10月, 2009 1 次提交
    • T
      futex: Handle spurious wake up · d58e6576
      Thomas Gleixner 提交于
      The futex code does not handle spurious wake up in futex_wait and
      futex_wait_requeue_pi.
      
      The code assumes that any wake up which was not caused by futex_wake /
      requeue or by a timeout was caused by a signal wake up and returns one
      of the syscall restart error codes.
      
      In case of a spurious wake up the signal delivery code which deals
      with the restart error codes is not invoked and we return that error
      code to user space. That causes applications which actually check the
      return codes to fail. Blaise reported that on preempt-rt a python test
      program run into a exception trap. -rt exposed that due to a built in
      spurious wake up accelerator :)
      
      Solve this by checking signal_pending(current) in the wake up path and
      handle the spurious wake up case w/o returning to user space.
      Reported-by: NBlaise Gassend <blaise@willowgarage.com>
      Debugged-by: NDarren Hart <dvhltc@us.ibm.com>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: stable@kernel.org
      LKML-Reference: <new-submission>
      d58e6576
  4. 13 10月, 2009 1 次提交
  5. 10 10月, 2009 2 次提交
    • R
      oprofile: warn on freeing event buffer too early · c0868934
      Robert Richter 提交于
      A race shouldn't happen since all workqueues or handlers are canceled
      or flushed before the event buffer is freed. A warning is triggered
      now if the buffer is freed too early.
      
      Also, this patch adds some comments about event buffer protection,
      reworks some code and adds code to clear buffer_pos during alloc and
      free of the event buffer.
      
      Cc: David Rientjes <rientjes@google.com>
      Cc: Stephane Eranian <eranian@google.com>
      Signed-off-by: NRobert Richter <robert.richter@amd.com>
      c0868934
    • D
      oprofile: fix race condition in event_buffer free · 066b3aa8
      David Rientjes 提交于
      Looking at the 2.6.31-rc9 code, it appears there is a race condition
      in the event_buffer cleanup code path (shutdown). This could lead to
      kernel panic as some CPUs may be operating on the event buffer AFTER
      it has been freed. The attached patch solves the problem and makes
      sure CPUs check if the buffer is not NULL before they access it as
      some may have been spinning on the mutex while the buffer was being
      freed.
      
      The race may happen if the buffer is freed during pending reads. But
      it is not clear why there are races in add_event_entry() since all
      workqueues or handlers are canceled or flushed before the event buffer
      is freed.
      Signed-off-by: NDavid Rientjes <rientjes@google.com>
      Signed-off-by: NStephane Eranian <eranian@google.com>
      Signed-off-by: NRobert Richter <robert.richter@amd.com>
      066b3aa8
  6. 09 10月, 2009 15 次提交
  7. 08 10月, 2009 12 次提交