1. 23 Mar, 2011 34 commits
  2. 22 Mar, 2011 6 commits
    • Linus Torvalds's avatar
      tty: stop using "delayed_work" in the tty layer · f23eb2b2
      Linus Torvalds authored
      
      Using delayed-work for tty flip buffers ends up causing us to wait for
      the next tick to complete some actions.  That's usually not all that
      noticeable, but for certain latency-critical workloads it ends up being
      totally unacceptable.
      
      As an extreme case of this, passing a token back-and-forth over a pty
      will take two ticks per iteration, so even just a thousand iterations
      will take 8 seconds assuming a common 250Hz configuration.
      
      Avoiding the whole delayed work issue brings that ping-pong test-case
      down to 0.009s on my machine.
      
      In more practical terms, this latency has been a performance problem for
      things like dive computer simulators (simulating the serial interface
      using the ptys) and for other environments (Alan mentions a CP/M emulator).
      Reported-by: default avatarJef Driesen <jefdriesen@telenet.be>
      Acked-by: default avatarGreg KH <gregkh@suse.de>
      Acked-by: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f23eb2b2
    • Christoph Lameter's avatar
      slub: Add statistics for this_cmpxchg_double failures · 4fdccdfb
      Christoph Lameter authored
      
      Add some statistics for debugging.
      Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
      Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
      4fdccdfb
    • Yehuda Sadeh's avatar
      libceph: add lingering request and watch/notify event framework · a40c4f10
      Yehuda Sadeh authored
      
      Lingering requests are requests that are sent to the OSD normally but
      tracked also after we get a successful request.  This keeps the OSD
      connection open and resends the original request if the object moves to
      another OSD.  The OSD can then send notification messages back to us
      if another client initiates a notify.
      
      This framework will be used by RBD so that the client gets notification
      when a snapshot is created by another node or tool.
      Signed-off-by: default avatarYehuda Sadeh <yehuda@hq.newdream.net>
      Signed-off-by: default avatarSage Weil <sage@newdream.net>
      a40c4f10
    • Simon Horman's avatar
      IPVS: Use global mutex in ip_vs_app.c · 736561a0
      Simon Horman authored
      
      As part of the work to make IPVS network namespace aware
      __ip_vs_app_mutex was replaced by a per-namespace lock,
      ipvs->app_mutex. ipvs->app_key is also supplied for debugging purposes.
      
      Unfortunately this implementation results in ipvs->app_key residing
      in non-static storage which at the very least causes a lockdep warning.
      
      This patch takes the rather heavy-handed approach of reinstating
      __ip_vs_app_mutex which will cover access to the ipvs->list_head
      of all network namespaces.
      
      [   12.610000] IPVS: Creating netns size=2456 id=0
      [   12.630000] IPVS: Registered protocols (TCP, UDP, SCTP, AH, ESP)
      [   12.640000] BUG: key ffff880003bbf1a0 not in .data!
      [   12.640000] ------------[ cut here ]------------
      [   12.640000] WARNING: at kernel/lockdep.c:2701 lockdep_init_map+0x37b/0x570()
      [   12.640000] Hardware name: Bochs
      [   12.640000] Pid: 1, comm: swapper Tainted: G        W 2.6.38-kexec-06330-g69b7efe-dirty #122
      [   12.650000] Call Trace:
      [   12.650000]  [<ffffffff8102e685>] warn_slowpath_common+0x75/0xb0
      [   12.650000]  [<ffffffff8102e6d5>] warn_slowpath_null+0x15/0x20
      [   12.650000]  [<ffffffff8105967b>] lockdep_init_map+0x37b/0x570
      [   12.650000]  [<ffffffff8105829d>] ? trace_hardirqs_on+0xd/0x10
      [   12.650000]  [<ffffffff81055ad8>] debug_mutex_init+0x38/0x50
      [   12.650000]  [<ffffffff8104bc4c>] __mutex_init+0x5c/0x70
      [   12.650000]  [<ffffffff81685ee7>] __ip_vs_app_init+0x64/0x86
      [   12.660000]  [<ffffffff81685a3b>] ? ip_vs_init+0x0/0xff
      [   12.660000]  [<ffffffff811b1c33>] T.620+0x43/0x170
      [   12.660000]  [<ffffffff811b1e9a>] ? register_pernet_subsys+0x1a/0x40
      [   12.660000]  [<ffffffff81685a3b>] ? ip_vs_init+0x0/0xff
      [   12.660000]  [<ffffffff81685a3b>] ? ip_vs_init+0x0/0xff
      [   12.660000]  [<ffffffff811b1db7>] register_pernet_operations+0x57/0xb0
      [   12.660000]  [<ffffffff81685a3b>] ? ip_vs_init+0x0/0xff
      [   12.670000]  [<ffffffff811b1ea9>] register_pernet_subsys+0x29/0x40
      [   12.670000]  [<ffffffff81685f19>] ip_vs_app_init+0x10/0x12
      [   12.670000]  [<ffffffff81685a87>] ip_vs_init+0x4c/0xff
      [   12.670000]  [<ffffffff8166562c>] do_one_initcall+0x7a/0x12e
      [   12.670000]  [<ffffffff8166583e>] kernel_init+0x13e/0x1c2
      [   12.670000]  [<ffffffff8128c134>] kernel_thread_helper+0x4/0x10
      [   12.670000]  [<ffffffff8128ad40>] ? restore_args+0x0/0x30
      [   12.680000]  [<ffffffff81665700>] ? kernel_init+0x0/0x1c2
      [   12.680000]  [<ffffffff8128c130>] ? kernel_thread_helper+0x0/0x1global0
      Signed-off-by: default avatarSimon Horman <horms@verge.net.au>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Julian Anastasov <ja@ssi.bg>
      Cc: Hans Schillstrom <hans@schillstrom.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      736561a0
    • Eric Dumazet's avatar
      snmp: SNMP_UPD_PO_STATS_BH() always called from softirq · 20246a80
      Eric Dumazet authored
      
      We dont need to test if we run from softirq context, we definitely are.
      
      This saves few instructions in ip_rcv() & ip_rcv_finish()
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      20246a80
    • Wei Yongjun's avatar
      xfrm: Fix initialize repl field of struct xfrm_state · a454f0cc
      Wei Yongjun authored
      Commit 'xfrm: Move IPsec replay detection functions to a separate file'
        (9fdc4883
      
      )
      introduce repl field to struct xfrm_state, and only initialize it
      under SA's netlink create path, the other path, such as pf_key,
      ipcomp/ipcomp6 etc, the repl field remaining uninitialize. So if
      the SA is created by pf_key, any input packet with SA's encryption
      algorithm will cause panic.
      
          int xfrm_input()
          {
              ...
              x->repl->advance(x, seq);
              ...
          }
      
      This patch fixed it by introduce new function __xfrm_init_state().
      
      Pid: 0, comm: swapper Not tainted 2.6.38-next+ #14 Bochs Bochs
      EIP: 0060:[<c078e5d5>] EFLAGS: 00010206 CPU: 0
      EIP is at xfrm_input+0x31c/0x4cc
      EAX: dd839c00 EBX: 00000084 ECX: 00000000 EDX: 01000000
      ESI: dd839c00 EDI: de3a0780 EBP: dec1de88 ESP: dec1de64
       DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
      Process swapper (pid: 0, ti=dec1c000 task=c09c0f20 task.ti=c0992000)
      Stack:
       00000000 00000000 00000002 c0ba27c0 00100000 01000000 de3a0798 c0ba27c0
       00000033 dec1de98 c0786848 00000000 de3a0780 dec1dea4 c0786868 00000000
       dec1debc c074ee56 e1da6b8c de3a0780 c074ed44 de3a07a8 dec1decc c074ef32
      Call Trace:
       [<c0786848>] xfrm4_rcv_encap+0x22/0x27
       [<c0786868>] xfrm4_rcv+0x1b/0x1d
       [<c074ee56>] ip_local_deliver_finish+0x112/0x1b1
       [<c074ed44>] ? ip_local_deliver_finish+0x0/0x1b1
       [<c074ef32>] NF_HOOK.clone.1+0x3d/0x44
       [<c074ef77>] ip_local_deliver+0x3e/0x44
       [<c074ed44>] ? ip_local_deliver_finish+0x0/0x1b1
       [<c074ec03>] ip_rcv_finish+0x30a/0x332
       [<c074e8f9>] ? ip_rcv_finish+0x0/0x332
       [<c074ef32>] NF_HOOK.clone.1+0x3d/0x44
       [<c074f188>] ip_rcv+0x20b/0x247
       [<c074e8f9>] ? ip_rcv_finish+0x0/0x332
       [<c072797d>] __netif_receive_skb+0x373/0x399
       [<c0727bc1>] netif_receive_skb+0x4b/0x51
       [<e0817e2a>] cp_rx_poll+0x210/0x2c4 [8139cp]
       [<c072818f>] net_rx_action+0x9a/0x17d
       [<c0445b5c>] __do_softirq+0xa1/0x149
       [<c0445abb>] ? __do_softirq+0x0/0x149
      Signed-off-by: default avatarWei Yongjun <yjwei@cn.fujitsu.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a454f0cc