1. 27 2月, 2010 29 次提交
  2. 26 2月, 2010 3 次提交
    • P
      perf_events: Simplify code by removing cpu argument to hw_perf_group_sched_in() · 6e37738a
      Peter Zijlstra 提交于
      Since the cpu argument to hw_perf_group_sched_in() is always
      smp_processor_id(), simplify the code a little by removing this argument
      and using the current cpu where needed.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: David Miller <davem@davemloft.net>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <1265890918.5396.3.camel@laptop>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      6e37738a
    • S
      perf_events: Add new start/stop PMU callbacks · d76a0812
      Stephane Eranian 提交于
      In certain situations, the kernel may need to stop and start the same
      event rapidly. The current PMU callbacks do not distinguish between stop
      and release (i.e., stop + free the resource). Thus, a counter may be
      released, then it will be immediately re-acquired. Event scheduling will
      again take place with no guarantee to assign the same counter. On some
      processors, this may event yield to failure to assign the event back due
      to competion between cores.
      
      This patch is adding a new pair of callback to stop and restart a counter
      without actually release the underlying counter resource. On stop, the
      counter is stopped, its values saved and that's it. On start, the value
      is reloaded and counter is restarted (on x86, actual restart is delayed
      until perf_enable()).
      Signed-off-by: NStephane Eranian <eranian@google.com>
      [ added fallback to ->enable/->disable for all other PMUs
        fixed x86_pmu_start() to call x86_pmu.enable()
        merged __x86_pmu_disable into x86_pmu_stop() ]
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <4b703875.0a04d00a.7896.ffffb824@mx.google.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      d76a0812
    • P
      rcu: Make rcu_read_lock_sched_held() take boot time into account · d9f1bb6a
      Paul E. McKenney 提交于
      Before the scheduler starts, all tasks are non-preemptible by
      definition. So, during that time, rcu_read_lock_sched_held()
      needs to always return "true".  This patch makes that be so.
      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
      LKML-Reference: <1267135607-7056-2-git-send-email-paulmck@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      d9f1bb6a
  3. 25 2月, 2010 8 次提交
    • J
      tracing: Fix ftrace_event_call alignment for use with gcc 4.5 · 86c38a31
      Jeff Mahoney 提交于
      GCC 4.5 introduces behavior that forces the alignment of structures to
       use the largest possible value. The default value is 32 bytes, so if
       some structures are defined with a 4-byte alignment and others aren't
       declared with an alignment constraint at all - it will align at 32-bytes.
      
       For things like the ftrace events, this results in a non-standard array.
       When initializing the ftrace subsystem, we traverse the _ftrace_events
       section and call the initialization callback for each event. When the
       structures are misaligned, we could be treating another part of the
       structure (or the zeroed out space between them) as a function pointer.
      
       This patch forces the alignment for all the ftrace_event_call structures
       to 4 bytes.
      
       Without this patch, the kernel fails to boot very early when built with
       gcc 4.5.
      
       It's trivial to check the alignment of the members of the array, so it
       might be worthwhile to add something to the build system to do that
       automatically. Unfortunately, that only covers this case. I've asked one
       of the gcc developers about adding a warning when this condition is seen.
      
      Cc: stable@kernel.org
      Signed-off-by: NJeff Mahoney <jeffm@suse.com>
      LKML-Reference: <4B85770B.6010901@suse.com>
      Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      86c38a31
    • P
      rcu: Accelerate grace period if last non-dynticked CPU · 8bd93a2c
      Paul E. McKenney 提交于
      Currently, rcu_needs_cpu() simply checks whether the current CPU
      has an outstanding RCU callback, which means that the last CPU
      to go into dyntick-idle mode might wait a few ticks for the
      relevant grace periods to complete.  However, if all the other
      CPUs are in dyntick-idle mode, and if this CPU is in a quiescent
      state (which it is for RCU-bh and RCU-sched any time that we are
      considering going into dyntick-idle mode), then the grace period
      is instantly complete.
      
      This patch therefore repeatedly invokes the RCU grace-period
      machinery in order to force any needed grace periods to complete
      quickly.  It does so a limited number of times in order to
      prevent starvation by an RCU callback function that might pass
      itself to call_rcu().
      
      However, if any CPU other than the current one is not in
      dyntick-idle mode, fall back to simply checking (with fix to bug
      noted by Lai Jiangshan).  Also, take advantage of last
      grace-period forcing, the opportunity to do so noted by Steve
      Rostedt.  And apply simplified #ifdef condition suggested by
      Frederic Weisbecker.
      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
      LKML-Reference: <1266887105-1528-15-git-send-email-paulmck@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      8bd93a2c
    • P
      vfs: Abstract rcu_dereference_check for files-fdtable use · af61b96b
      Paul E. McKenney 提交于
      Create an rcu_dereference_check_fdtable() that encapsulates the
      rcu_dereference_check() condition for fcheck_files() use.  This
      has the beneficial side-effect of getting rid of a very long
      line.
      Suggested-by: NPeter Zijlstra <peterz@infradead.org>
      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
      LKML-Reference: <1266887105-1528-9-git-send-email-paulmck@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      af61b96b
    • P
      vfs: Apply lockdep-based checking to rcu_dereference() uses · 7dc52157
      Paul E. McKenney 提交于
      Add lockdep-ified RCU primitives to alloc_fd(), files_fdtable()
      and fcheck_files().
      
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      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: Alexander Viro <viro@zeniv.linux.org.uk>
      LKML-Reference: <1266887105-1528-8-git-send-email-paulmck@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      7dc52157
    • P
      sched: Use lockdep-based checking on rcu_dereference() · d11c563d
      Paul E. McKenney 提交于
      Update the rcu_dereference() usages to take advantage of the new
      lockdep-based checking.
      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
      LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com>
      [ -v2: fix allmodconfig missing symbol export build failure on x86 ]
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      d11c563d
    • P
      net: Add checking to rcu_dereference() primitives · a898def2
      Paul E. McKenney 提交于
      Update rcu_dereference() primitives to use new lockdep-based
      checking. The rcu_dereference() in __in6_dev_get() may be
      protected either by rcu_read_lock() or RTNL, per Eric Dumazet.
      The rcu_dereference() in __sk_free() is protected by the fact
      that it is never reached if an update could change it.  Check
      for this by using rcu_dereference_check() to verify that the
      struct sock's ->sk_wmem_alloc counter is zero.
      Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
      Acked-by: NDavid S. Miller <davem@davemloft.net>
      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
      LKML-Reference: <1266887105-1528-5-git-send-email-paulmck@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      a898def2
    • P
      rcu: Disable lockdep checking in RCU list-traversal primitives · 3120438a
      Paul E. McKenney 提交于
      The theory is that use of bare rcu_dereference() is more prone
      to error than use of the RCU list-traversal primitives.
      Therefore, disable lockdep RCU read-side critical-section
      checking in these primitives for the time being.  Once all of
      the rcu_dereference() uses have been dealt with, it may be time
      to re-enable lockdep checking for the RCU list-traversal
      primitives.
      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
      LKML-Reference: <1266887105-1528-4-git-send-email-paulmck@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3120438a
    • P
      rcu: Integrate rcu_dereference_check() message into lockdep · 0632eb3d
      Paul E. McKenney 提交于
      Make rcu_dereference_check() print the list of held locks in
      addition to the stack dump to ease debugging.
      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
      LKML-Reference: <1266887105-1528-3-git-send-email-paulmck@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      0632eb3d