1. 28 Apr, 2009 2 commits
    • Roger Quadros's avatar
      Bluetooth: Ensure that HCI sysfs add/del is preempt safe · f3784d83
      Roger Quadros authored
      
      
      Use a different work_struct variables for add_conn() and del_conn() and
      use single work queue instead of two for adding and deleting connections.
      
      It eliminates the following error on a preemptible kernel:
      
      [  204.358032] Unable to handle kernel NULL pointer dereference at virtual address 0000000c
      [  204.370697] pgd = c0004000
      [  204.373443] [0000000c] *pgd=00000000
      [  204.378601] Internal error: Oops: 17 [#1] PREEMPT
      [  204.383361] Modules linked in: vfat fat rfcomm sco l2cap sd_mod scsi_mod iphb pvr2d drm omaplfb ps
      [  204.438537] CPU: 0    Not tainted  (2.6.28-maemo2 #1)
      [  204.443664] PC is at klist_put+0x2c/0xb4
      [  204.447601] LR is at klist_put+0x18/0xb4
      [  204.451568] pc : [<c0270f08>]    lr : [<c0270ef4>]    psr: a0000113
      [  204.451568] sp : cf1b3f10  ip : cf1b3f10  fp : cf1b3f2c
      [  204.463104] r10: 00000000  r9 : 00000000  r8 : bf08029c
      [  204.468353] r7 : c7869200  r6 : cfbe2690  r5 : c78692c8  r4 : 00000001
      [  204.474945] r3 : 00000001  r2 : cf1b2000  r1 : 00000001  r0 : 00000000
      [  204.481506] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM Segment kernel
      [  204.488861] Control: 10c5387d  Table: 887fc018  DAC: 00000017
      [  204.494628] Process btdelconn (pid: 515, stack limit = 0xcf1b22e0)
      Signed-off-by: default avatarRoger Quadros <ext-roger.quadros@nokia.com>
      Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
      f3784d83
    • Eric Dumazet's avatar
      net: Avoid extra wakeups of threads blocked in wait_for_packet() · bf368e4e
      Eric Dumazet authored
      In 2.6.25 we added UDP mem accounting.
      
      This unfortunatly added a penalty when a frame is transmitted, since
      we have at TX completion time to call sock_wfree() to perform necessary
      memory accounting. This calls sock_def_write_space() and utimately
      scheduler if any thread is waiting on the socket.
      Thread(s) waiting for an incoming frame was scheduled, then had to sleep
      again as event was meaningless.
      
      (All threads waiting on a socket are using same sk_sleep anchor)
      
      This adds lot of extra wakeups and increases latencies, as noted
      by Christoph Lameter, and slows down softirq handler.
      
      Reference : http://marc.info/?l=linux-netdev&m=124060437012283&w=2 
      
      Fortunatly, Davide Libenzi recently added concept of keyed wakeups
      into kernel, and particularly for sockets (see commit
      37e5540b
      
       
      epoll keyed wakeups: make sockets use keyed wakeups)
      
      Davide goal was to optimize epoll, but this new wakeup infrastructure
      can help non epoll users as well, if they care to setup an appropriate
      handler.
      
      This patch introduces new DEFINE_WAIT_FUNC() helper and uses it
      in wait_for_packet(), so that only relevant event can wakeup a thread
      blocked in this function.
      
      Trace of function calls from bnx2 TX completion bnx2_poll_work() is :
      __kfree_skb()
       skb_release_head_state()
        sock_wfree()
         sock_def_write_space()
          __wake_up_sync_key()
           __wake_up_common()
            receiver_wake_function() : Stops here since thread is waiting for an INPUT
      Reported-by: default avatarChristoph Lameter <cl@linux.com>
      Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bf368e4e
  2. 27 Apr, 2009 12 commits
  3. 25 Apr, 2009 2 commits
  4. 24 Apr, 2009 4 commits
  5. 22 Apr, 2009 10 commits
  6. 21 Apr, 2009 10 commits