1. 03 7月, 2013 1 次提交
    • D
      sync: don't block the flusher thread waiting on IO · 7747bd4b
      Dave Chinner 提交于
      When sync does it's WB_SYNC_ALL writeback, it issues data Io and
      then immediately waits for IO completion. This is done in the
      context of the flusher thread, and hence completely ties up the
      flusher thread for the backing device until all the dirty inodes
      have been synced. On filesystems that are dirtying inodes constantly
      and quickly, this means the flusher thread can be tied up for
      minutes per sync call and hence badly affect system level write IO
      performance as the page cache cannot be cleaned quickly.
      
      We already have a wait loop for IO completion for sync(2), so cut
      this out of the flusher thread and delegate it to wait_sb_inodes().
      Hence we can do rapid IO submission, and then wait for it all to
      complete.
      
      Effect of sync on fsmark before the patch:
      
      FSUse%        Count         Size    Files/sec     App Overhead
      .....
           0       640000         4096      35154.6          1026984
           0       720000         4096      36740.3          1023844
           0       800000         4096      36184.6           916599
           0       880000         4096       1282.7          1054367
           0       960000         4096       3951.3           918773
           0      1040000         4096      40646.2           996448
           0      1120000         4096      43610.1           895647
           0      1200000         4096      40333.1           921048
      
      And a single sync pass took:
      
        real    0m52.407s
        user    0m0.000s
        sys     0m0.090s
      
      After the patch, there is no impact on fsmark results, and each
      individual sync(2) operation run concurrently with the same fsmark
      workload takes roughly 7s:
      
        real    0m6.930s
        user    0m0.000s
        sys     0m0.039s
      
      IOWs, sync is 7-8x faster on a busy filesystem and does not have an
      adverse impact on ongoing async data write operations.
      Signed-off-by: NDave Chinner <dchinner@redhat.com>
      Reviewed-by: NJan Kara <jack@suse.cz>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7747bd4b
  2. 01 7月, 2013 2 次提交
    • T
      jbd2: invalidate handle if jbd2_journal_restart() fails · 41a5b913
      Theodore Ts'o 提交于
      If jbd2_journal_restart() fails the handle will have been disconnected
      from the current transaction.  In this situation, the handle must not
      be used for for any jbd2 function other than jbd2_journal_stop().
      Enforce this with by treating a handle which has a NULL transaction
      pointer as an aborted handle, and issue a kernel warning if
      jbd2_journal_extent(), jbd2_journal_get_write_access(),
      jbd2_journal_dirty_metadata(), etc. is called with an invalid handle.
      
      This commit also fixes a bug where jbd2_journal_stop() would trip over
      a kernel jbd2 assertion check when trying to free an invalid handle.
      
      Also move the responsibility of setting current->journal_info to
      start_this_handle(), simplifying the three users of this function.
      Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
      Reported-by: NYounger Liu <younger.liu@huawei.com>
      Cc: Jan Kara <jack@suse.cz>
      41a5b913
    • T
      ext4: translate flag bits to strings in tracepoints · 21ddd568
      Theodore Ts'o 提交于
      Translate the bitfields used in various flags argument to strings to
      make the tracepoint output more human-readable.
      Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
      21ddd568
  3. 29 6月, 2013 8 次提交
  4. 27 6月, 2013 1 次提交
    • N
      net: fix kernel deadlock with interface rename and netdev name retrieval. · 5dbe7c17
      Nicolas Schichan 提交于
      When the kernel (compiled with CONFIG_PREEMPT=n) is performing the
      rename of a network interface, it can end up waiting for a workqueue
      to complete. If userland is able to invoke a SIOCGIFNAME ioctl or a
      SO_BINDTODEVICE getsockopt in between, the kernel will deadlock due to
      the fact that read_secklock_begin() will spin forever waiting for the
      writer process (the one doing the interface rename) to update the
      devnet_rename_seq sequence.
      
      This patch fixes the problem by adding a helper (netdev_get_name())
      and using it in the code handling the SIOCGIFNAME ioctl and
      SO_BINDTODEVICE setsockopt.
      
      The netdev_get_name() helper uses raw_seqcount_begin() to avoid
      spinning forever, waiting for devnet_rename_seq->sequence to become
      even. cond_resched() is used in the contended case, before retrying
      the access to give the writer process a chance to finish.
      
      The use of raw_seqcount_begin() will incur some unneeded work in the
      reader process in the contended case, but this is better than
      deadlocking the system.
      Signed-off-by: NNicolas Schichan <nschichan@freebox.fr>
      Acked-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      5dbe7c17
  5. 26 6月, 2013 2 次提交
  6. 25 6月, 2013 2 次提交
  7. 24 6月, 2013 3 次提交
    • R
      ACPI / dock / PCI: Synchronous handling of dock events for PCI devices · 21a31013
      Rafael J. Wysocki 提交于
      The interactions between the ACPI dock driver and the ACPI-based PCI
      hotplug (acpiphp) are currently problematic because of ordering
      issues during hot-remove operations.
      
      First of all, the current ACPI glue code expects that physical
      devices will always be deleted before deleting the companion ACPI
      device objects.  Otherwise, acpi_unbind_one() will fail with a
      warning message printed to the kernel log, for example:
      
      [  185.026073] usb usb5: Oops, 'acpi_handle' corrupt
      [  185.035150] pci 0000:1b:00.0: Oops, 'acpi_handle' corrupt
      [  185.035515] pci 0000:18:02.0: Oops, 'acpi_handle' corrupt
      [  180.013656]  port1: Oops, 'acpi_handle' corrupt
      
      This means, in particular, that struct pci_dev objects have to
      be deleted before the struct acpi_device objects they are "glued"
      with.
      
      Now, the following happens the during the undocking of an ACPI-based
      dock station:
       1) hotplug_dock_devices() invokes registered hotplug callbacks to
          destroy physical devices associated with the ACPI device objects
          depending on the dock station.  It calls dd->ops->handler() for
          each of those device objects.
       2) For PCI devices dd->ops->handler() points to
          handle_hotplug_event_func() that queues up a separate work item
          to execute _handle_hotplug_event_func() for the given device and
          returns immediately.  That work item will be executed later.
       3) hotplug_dock_devices() calls dock_remove_acpi_device() for each
          device depending on the dock station.  This runs acpi_bus_trim()
          for each of them, which causes the underlying ACPI device object
          to be destroyed, but the work items queued up by
          handle_hotplug_event_func() haven't been started yet.
       4) _handle_hotplug_event_func() queued up in step 2) are executed
          and cause the above failure to happen, because the PCI devices
          they handle do not have the companion ACPI device objects any
          more (those objects have been deleted in step 3).
      
      The possible breakage doesn't end here, though, because
      hotplug_dock_devices() may return before at least some of the
      _handle_hotplug_event_func() work items spawned by it have a
      chance to complete and then undock() will cause _DCK to be
      evaluated and that will cause the devices handled by the
      _handle_hotplug_event_func() to go away possibly while they are
      being accessed.
      
      This means that dd->ops->handler() for PCI devices should not point
      to handle_hotplug_event_func().  Instead, it should point to a
      function that will do the work of _handle_hotplug_event_func()
      synchronously.  For this reason, introduce such a function,
      hotplug_event_func(), and modity acpiphp_dock_ops to point to
      it as the handler.
      
      Unfortunately, however, this is not sufficient, because if the dock
      code were not changed further, hotplug_event_func() would now
      deadlock with hotplug_dock_devices() that called it, since it would
      run unregister_hotplug_dock_device() which in turn would attempt to
      acquire the dock station's hp_lock mutex already acquired by
      hotplug_dock_devices().
      
      To resolve that deadlock use the observation that
      unregister_hotplug_dock_device() won't need to acquire hp_lock
      if PCI bridges the devices on the dock station depend on are
      prevented from being removed prematurely while the first loop in
      hotplug_dock_devices() is in progress.
      
      To make that possible, introduce a mechanism by which the callers of
      register_hotplug_dock_device() can provide "init" and "release"
      routines that will be executed, respectively, during the addition
      and removal of the physical device object associated with the
      given ACPI device handle.  Make acpiphp use two new functions,
      acpiphp_dock_init() and acpiphp_dock_release(), that call
      get_bridge() and put_bridge(), respectively, on the acpiphp bridge
      holding the given device, for this purpose.
      
      In addition to that, remove the dock station's list of
      "hotplug devices" and make the dock code always walk the whole list
      of "dependent devices" instead in such a way that the loops in
      hotplug_dock_devices() and dock_event() (replacing the loops over
      "hotplug devices") will take references to the list entries that
      register_hotplug_dock_device() has been called for.  That prevents
      the "release" routines associated with those entries from being
      called while the given entry is being processed and for PCI
      devices this means that their bridges won't be removed (by a
      concurrent thread) while hotplug_event_func() handling them is
      being executed.
      
      This change is based on two earlier patches from Jiang Liu.
      
      References: https://bugzilla.kernel.org/show_bug.cgi?id=59501Reported-and-tested-by: NAlexander E. Patrakov <patrakov@gmail.com>
      Tracked-down-by: NJiang Liu <jiang.liu@huawei.com>
      Tested-by: NIllya Klymov <xanf@xanf.me>
      Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      Acked-by: NYinghai Lu <yinghai@kernel.org>
      Cc: 3.9+ <stable@vger.kernel.org>
      21a31013
    • M
      ARM: edma: Add EDMA crossbar event mux support · 2646a0e5
      Matt Porter 提交于
      EDMA supports a cross bar which provides ability
      to mux additional events into physical channels
      present in the channel controller.
      
      This is required when the number of events present
      in the system are more than number of available
      physical channels.
      
      Changes by Joel:
      * Split EDMA xbar support out of original EDMA DT parsing patch
      to keep it easier for review.
      * Rewrite shift and offset calculation.
      Suggested-by: NSekhar Nori <nsekhar@ti.com>
      Suggested by: Andy Shevchenko <andy.shevchenko@gmail.com>
      Signed-off-by: NJoel A Fernandes <joelagnel@ti.com>
      Acked-by: NArnd Bergmann <arnd@arndb.de>
      [nsekhar@ti.com: fix checkpatch errors and a minor coding improvement]
      Signed-off-by: NSekhar Nori <nsekhar@ti.com>
      2646a0e5
    • M
      ARM: edma: Add DT and runtime PM support to the private EDMA API · 6cba4355
      Matt Porter 提交于
      Adds support for parsing the TI EDMA DT data into the required EDMA
      private API platform data. Enables runtime PM support to initialize
      the EDMA hwmod. Enables build on OMAP.
      
      Changes by Joel:
      * Setup default one-to-one mapping for queue_priority and queue_tc
      mapping as discussed in [1].
      * Split out xbar stuff to separate patch. [1]
      * Dropped unused DT helper to convert to array
      * Fixed dangling pointer issue with Sekhar's changes
      
      [1] https://patchwork.kernel.org/patch/2226761/Signed-off-by: NMatt Porter <mporter@ti.com>
      [nsekhar@ti.com: fix checkpatch errors, build breakages. Introduce
      edma_setup_info_from_dt() as part of that effort]
      Signed-off-by: NJoel A Fernandes <joelagnel@ti.com>
      Acked-by: NArnd Bergmann <arnd@arndb.de>
      Signed-off-by: NSekhar Nori <nsekhar@ti.com>
      6cba4355
  8. 20 6月, 2013 5 次提交
  9. 19 6月, 2013 9 次提交
    • D
      FS-Cache: The retrieval remaining-pages counter needs to be atomic_t · 1bb4b7f9
      David Howells 提交于
      struct fscache_retrieval contains a count of the number of pages that still
      need some processing (n_pages).  This is decremented as the pages are
      processed.
      
      However, this needs to be atomic as fscache_retrieval_complete() (I think) just
      occasionally may be called from cachefiles_read_backing_file() and
      cachefiles_read_copier() simultaneously.
      
      This happens when an fscache_read_or_alloc_pages() request containing a lot of
      pages (say a couple of hundred) is being processed.  The read on each backing
      page is dispatched individually because we need to insert a monitor into the
      waitqueue to catch when the read completes.  However, under low-memory
      conditions, we might be forced to wait in the allocator - and this gives the
      I/O on the backing page a chance to complete first.
      
      When the I/O completes, fscache_enqueue_retrieval() chucks the retrieval onto
      the workqueue without waiting for the operation to finish the initial I/O
      dispatch (we want to release any pages we can as soon as we can), thus both can
      end up running simultaneously and potentially attempting to partially complete
      the retrieval simultaneously (ENOMEM may occur, backing pages may already be in
      the page cache).
      
      This was demonstrated by parallelling the non-atomic counter with an atomic
      counter and printing both of them when the assertion fails.  At this point, the
      atomic counter has reached zero, but the non-atomic counter has not.
      
      To fix this, make the counter an atomic_t.
      
      This results in the following bug appearing
      
      	FS-Cache: Assertion failed
      	3 == 5 is false
      	------------[ cut here ]------------
      	kernel BUG at fs/fscache/operation.c:421!
      
      or
      
      	FS-Cache: Assertion failed
      	3 == 5 is false
      	------------[ cut here ]------------
      	kernel BUG at fs/fscache/operation.c:414!
      
      With a backtrace like the following:
      
      RIP: 0010:[<ffffffffa0211b1d>] fscache_put_operation+0x1ad/0x240 [fscache]
      Call Trace:
       [<ffffffffa0213185>] fscache_retrieval_work+0x55/0x270 [fscache]
       [<ffffffffa0213130>] ? fscache_retrieval_work+0x0/0x270 [fscache]
       [<ffffffff81090b10>] worker_thread+0x170/0x2a0
       [<ffffffff81096d10>] ? autoremove_wake_function+0x0/0x40
       [<ffffffff810909a0>] ? worker_thread+0x0/0x2a0
       [<ffffffff81096966>] kthread+0x96/0xa0
       [<ffffffff8100c0ca>] child_rip+0xa/0x20
       [<ffffffff810968d0>] ? kthread+0x0/0xa0
       [<ffffffff8100c0c0>] ? child_rip+0x0/0x20
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Reviewed-and-tested-By: NMilosz Tanski <milosz@adfin.com>
      Acked-by: NJeff Layton <jlayton@redhat.com>
      1bb4b7f9
    • D
      FS-Cache: Simplify cookie retention for fscache_objects, fixing oops · 1362729b
      David Howells 提交于
      Simplify the way fscache cache objects retain their cookie.  The way I
      implemented the cookie storage handling made synchronisation a pain (ie. the
      object state machine can't rely on the cookie actually still being there).
      
      Instead of the the object being detached from the cookie and the cookie being
      freed in __fscache_relinquish_cookie(), we defer both operations:
      
       (*) The detachment of the object from the list in the cookie now takes place
           in fscache_drop_object() and is thus governed by the object state machine
           (fscache_detach_from_cookie() has been removed).
      
       (*) The release of the cookie is now in fscache_object_destroy() - which is
           called by the cache backend just before it frees the object.
      
      This means that the fscache_cookie struct is now available to the cache all the
      way through from ->alloc_object() to ->drop_object() and ->put_object() -
      meaning that it's no longer necessary to take object->lock to guarantee access.
      
      However, __fscache_relinquish_cookie() doesn't wait for the object to go all
      the way through to destruction before letting the netfs proceed.  That would
      massively slow down the netfs.  Since __fscache_relinquish_cookie() leaves the
      cookie around, in must therefore break all attachments to the netfs - which
      includes ->def, ->netfs_data and any outstanding page read/writes.
      
      To handle this, struct fscache_cookie now has an n_active counter:
      
       (1) This starts off initialised to 1.
      
       (2) Any time the cache needs to get at the netfs data, it calls
           fscache_use_cookie() to increment it - if it is not zero.  If it was zero,
           then access is not permitted.
      
       (3) When the cache has finished with the data, it calls fscache_unuse_cookie()
           to decrement it.  This does a wake-up on it if it reaches 0.
      
       (4) __fscache_relinquish_cookie() decrements n_active and then waits for it to
           reach 0.  The initialisation to 1 in step (1) ensures that we only get
           wake ups when we're trying to get rid of the cookie.
      
      This leaves __fscache_relinquish_cookie() a lot simpler.
      
      
      ***
      This fixes a problem in the current code whereby if fscache_invalidate() is
      followed sufficiently quickly by fscache_relinquish_cookie() then it is
      possible for __fscache_relinquish_cookie() to have detached the cookie from the
      object and cleared the pointer before a thread is dispatched to process the
      invalidation state in the object state machine.
      
      Since the pending write clearance was deferred to the invalidation state to
      make it asynchronous, we need to either wait in relinquishment for the stores
      tree to be cleared in the invalidation state or we need to handle the clearance
      in relinquishment.
      
      Further, if the relinquishment code does clear the tree, then the invalidation
      state need to make the clearance contingent on still having the cookie to hand
      (since that's where the tree is rooted) and we have to prevent the cookie from
      disappearing for the duration.
      
      This can lead to an oops like the following:
      
      BUG: unable to handle kernel NULL pointer dereference at 000000000000000c
      ...
      RIP: 0010:[<ffffffff8151023e>] _spin_lock+0xe/0x30
      ...
      CR2: 000000000000000c ...
      ...
      Process kslowd002 (...)
      ....
      Call Trace:
       [<ffffffffa01c3278>] fscache_invalidate_writes+0x38/0xd0 [fscache]
       [<ffffffff810096f0>] ? __switch_to+0xd0/0x320
       [<ffffffff8105e759>] ? find_busiest_queue+0x69/0x150
       [<ffffffff8110ddd4>] ? slow_work_enqueue+0x104/0x180
       [<ffffffffa01c1303>] fscache_object_slow_work_execute+0x5e3/0x9d0 [fscache]
       [<ffffffff81096b67>] ? bit_waitqueue+0x17/0xd0
       [<ffffffff8110e233>] slow_work_execute+0x233/0x310
       [<ffffffff8110e515>] slow_work_thread+0x205/0x360
       [<ffffffff81096ca0>] ? autoremove_wake_function+0x0/0x40
       [<ffffffff8110e310>] ? slow_work_thread+0x0/0x360
       [<ffffffff81096936>] kthread+0x96/0xa0
       [<ffffffff8100c0ca>] child_rip+0xa/0x20
       [<ffffffff810968a0>] ? kthread+0x0/0xa0
       [<ffffffff8100c0c0>] ? child_rip+0x0/0x20
      
      The parameter to fscache_invalidate_writes() was object->cookie which is NULL.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Tested-By: NMilosz Tanski <milosz@adfin.com>
      Acked-by: NJeff Layton <jlayton@redhat.com>
      1362729b
    • D
      FS-Cache: Fix object state machine to have separate work and wait states · caaef690
      David Howells 提交于
      Fix object state machine to have separate work and wait states as that makes
      it easier to envision.
      
      There are now three kinds of state:
      
       (1) Work state.  This is an execution state.  No event processing is performed
           by a work state.  The function attached to a work state returns a pointer
           indicating the next state to which the OSM should transition.  Returning
           NO_TRANSIT repeats the current state, but goes back to the scheduler
           first.
      
       (2) Wait state.  This is an event processing state.  No execution is
           performed by a wait state.  Wait states are just tables of "if event X
           occurs, clear it and transition to state Y".  The dispatcher returns to
           the scheduler if none of the events in which the wait state has an
           interest are currently pending.
      
       (3) Out-of-band state.  This is a special work state.  Transitions to normal
           states can be overridden when an unexpected event occurs (eg. I/O error).
           Instead the dispatcher disables and clears the OOB event and transits to
           the specified work state.  This then acts as an ordinary work state,
           though object->state points to the overridden destination.  Returning
           NO_TRANSIT resumes the overridden transition.
      
      In addition, the states have names in their definitions, so there's no need for
      tables of state names.  Further, the EV_REQUEUE event is no longer necessary as
      that is automatic for work states.
      
      Since the states are now separate structs rather than values in an enum, it's
      not possible to use comparisons other than (non-)equality between them, so use
      some object->flags to indicate what phase an object is in.
      
      The EV_RELEASE, EV_RETIRE and EV_WITHDRAW events have been squished into one
      (EV_KILL).  An object flag now carries the information about retirement.
      
      Similarly, the RELEASING, RECYCLING and WITHDRAWING states have been merged
      into an KILL_OBJECT state and additional states have been added for handling
      waiting dependent objects (JUMPSTART_DEPS and KILL_DEPENDENTS).
      
      A state has also been added for synchronising with parent object initialisation
      (WAIT_FOR_PARENT) and another for initiating look up (PARENT_READY).
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Tested-By: NMilosz Tanski <milosz@adfin.com>
      Acked-by: NJeff Layton <jlayton@redhat.com>
      caaef690
    • D
      FS-Cache: Wrap checks on object state · 493f7bc1
      David Howells 提交于
      Wrap checks on object state (mostly outside of fs/fscache/object.c) with
      inline functions so that the mechanism can be replaced.
      
      Some of the state checks within object.c are left as-is as they will be
      replaced.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Tested-By: NMilosz Tanski <milosz@adfin.com>
      Acked-by: NJeff Layton <jlayton@redhat.com>
      493f7bc1
    • D
      FS-Cache: Uninline fscache_object_init() · 610be24e
      David Howells 提交于
      Uninline fscache_object_init() so as not to expose some of the FS-Cache
      internals to the cache backend.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Tested-By: NMilosz Tanski <milosz@adfin.com>
      Acked-by: NJeff Layton <jlayton@redhat.com>
      610be24e
    • S
      tracing/context-tracking: Add preempt_schedule_context() for tracing · 29bb9e5a
      Steven Rostedt 提交于
      Dave Jones hit the following bug report:
      
       ===============================
       [ INFO: suspicious RCU usage. ]
       3.10.0-rc2+ #1 Not tainted
       -------------------------------
       include/linux/rcupdate.h:771 rcu_read_lock() used illegally while idle!
       other info that might help us debug this:
       RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0
       RCU used illegally from extended quiescent state!
       2 locks held by cc1/63645:
        #0:  (&rq->lock){-.-.-.}, at: [<ffffffff816b39fd>] __schedule+0xed/0x9b0
        #1:  (rcu_read_lock){.+.+..}, at: [<ffffffff8109d645>] cpuacct_charge+0x5/0x1f0
      
       CPU: 1 PID: 63645 Comm: cc1 Not tainted 3.10.0-rc2+ #1 [loadavg: 40.57 27.55 13.39 25/277 64369]
       Hardware name: Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H, BIOS F12a 04/23/2010
        0000000000000000 ffff88010f78fcf8 ffffffff816ae383 ffff88010f78fd28
        ffffffff810b698d ffff88011c092548 000000000023d073 ffff88011c092500
        0000000000000001 ffff88010f78fd60 ffffffff8109d7c5 ffffffff8109d645
       Call Trace:
        [<ffffffff816ae383>] dump_stack+0x19/0x1b
        [<ffffffff810b698d>] lockdep_rcu_suspicious+0xfd/0x130
        [<ffffffff8109d7c5>] cpuacct_charge+0x185/0x1f0
        [<ffffffff8109d645>] ? cpuacct_charge+0x5/0x1f0
        [<ffffffff8108dffc>] update_curr+0xec/0x240
        [<ffffffff8108f528>] put_prev_task_fair+0x228/0x480
        [<ffffffff816b3a71>] __schedule+0x161/0x9b0
        [<ffffffff816b4721>] preempt_schedule+0x51/0x80
        [<ffffffff816b4800>] ? __cond_resched_softirq+0x60/0x60
        [<ffffffff816b6824>] ? retint_careful+0x12/0x2e
        [<ffffffff810ff3cc>] ftrace_ops_control_func+0x1dc/0x210
        [<ffffffff816be280>] ftrace_call+0x5/0x2f
        [<ffffffff816b681d>] ? retint_careful+0xb/0x2e
        [<ffffffff816b4805>] ? schedule_user+0x5/0x70
        [<ffffffff816b4805>] ? schedule_user+0x5/0x70
        [<ffffffff816b6824>] ? retint_careful+0x12/0x2e
       ------------[ cut here ]------------
      
      What happened was that the function tracer traced the schedule_user() code
      that tells RCU that the system is coming back from userspace, and to
      add the CPU back to the RCU monitoring.
      
      Because the function tracer does a preempt_disable/enable_notrace() calls
      the preempt_enable_notrace() checks the NEED_RESCHED flag. If it is set,
      then preempt_schedule() is called. But this is called before the user_exit()
      function can inform the kernel that the CPU is no longer in user mode and
      needs to be accounted for by RCU.
      
      The fix is to create a new preempt_schedule_context() that checks if
      the kernel is still in user mode and if so to switch it to kernel mode
      before calling schedule. It also switches back to user mode coming back
      from schedule in need be.
      
      The only user of this currently is the preempt_enable_notrace(), which is
      only used by the tracing subsystem.
      Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
      Link: http://lkml.kernel.org/r/1369423420.6828.226.camel@gandalf.local.homeSigned-off-by: NIngo Molnar <mingo@kernel.org>
      29bb9e5a
    • F
      ARM: dts: Protect pinctrl headers against multiple inclusions · ac25da7f
      Florian Vaussard 提交于
      Pinctrl headers were not protected with #ifndef.
      Signed-off-by: NFlorian Vaussard <florian.vaussard@epfl.ch>
      Acked-by: NGrant Likely <grant.likely@secretlab.ca>
      Signed-off-by: NBenoit Cousson <benoit.cousson@linaro.org>
      ac25da7f
    • F
      ARM: dts: AM33XX: Specific pinctrl header · 3f2d1658
      Florian Vaussard 提交于
      The pinctrl IP inside the AM33XX family differs slightly from
      what is found on OMAP2+. Define a specific header to take account
      of the differences.
      Signed-off-by: NFlorian Vaussard <florian.vaussard@epfl.ch>
      Tested-by: NAfzal Mohammed <afzal@ti.com>
      Signed-off-by: NBenoit Cousson <benoit.cousson@linaro.org>
      3f2d1658
    • F
      ARM: dts: OMAP2+: Header file for pinctrl constants · 10a3472a
      Florian Vaussard 提交于
      Most of the constants are taken from arch/arm/mach-omap2/mux.h.
      Define some others for the PIN_OUTPUT_* flavours.
      Signed-off-by: NFlorian Vaussard <florian.vaussard@epfl.ch>
      Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
      Reviewed-by: NStephen Warren <swarren@nvidia.com>
      Signed-off-by: NBenoit Cousson <benoit.cousson@linaro.org>
      10a3472a
  10. 18 6月, 2013 7 次提交