target/linux/s3c24xx/patches-2.6.26/1213-sdio-use-interruptible-sleep-in-kthread-main-loops.patch

   1 From cba59b243d542f3de9c534d99b2f3f33e50b3ebb Mon Sep 17 00:00:00 2001
   2 From: Jason Uhlenkott <jasonuhl@jasonuhl.org>
   3 Date: Fri, 25 Jul 2008 23:06:20 +0100
   4 Subject: [PATCH] sdio: use interruptible sleep in kthread main loops
   5
   6 My FreeRunner's load average was leveling off at 2.00 as a result of
   7 these two kernel threads:
   8
   9 SDIO Helper   D c02b4500     0   255      2
  10 [<c02b4298>] (schedule+0x0/0x2d4) from [<c02b4040>] (__down+0x100/0x158)
  11 [<c02b3f40>] (__down+0x0/0x158) from [<c02b3e2c>] (__down_failed+0xc/0x20)
  12  r7:00000000 r6:c01fbd64 r5:c7cb7134 r4:c7d58000
  13 [<c01fa6fc>] (CardDetectHelperFunction+0x0/0x1ac) from [<c01fbd80>] (HelperLaunch+0x1c/0x28)
  14  r5:c7cb7134 r4:c7cb7134
  15 [<c01fbd64>] (HelperLaunch+0x0/0x28) from [<c005bbd0>] (kthread+0x60/0x94)
  16  r4:c7d58000
  17 [<c005bb70>] (kthread+0x0/0x94) from [<c0048f7c>] (do_exit+0x0/0x744)
  18  r6:00000000 r5:00000000 r4:00000000
  19
  20 SDIO Helper   D c02b4500     0   259      2
  21 [<c02b4298>] (schedule+0x0/0x2d4) from [<c02b4040>] (__down+0x100/0x158)
  22 [<c02b3f40>] (__down+0x0/0x158) from [<c02b3e2c>] (__down_failed+0xc/0x20)
  23  r7:c0382bb4 r6:c0382b34 r5:c7d5a000 r4:00000001
  24 [<c01f9104>] (SDIOIrqHelperFunction+0x0/0x29c) from [<c01fbd80>] (HelperLaunch+0x1c/0x28)
  25  r8:00000000 r7:00000000 r6:c01fbd64 r5:c0382bb4 r4:c0382bb4
  26 [<c01fbd64>] (HelperLaunch+0x0/0x28) from [<c005bbd0>] (kthread+0x60/0x94)
  27  r4:c7d5a000
  28 [<c005bb70>] (kthread+0x0/0x94) from [<c0048f7c>] (do_exit+0x0/0x744)
  29  r6:00000000 r5:00000000 r4:00000000
  30
  31 This fixes them to use interruptible sleep primitives while waiting in
  32 their main loops, as is conventional for kernel threads.  They can't
  33 actually be interrupted since kernel threads ignore all signals, but
  34 by sleeping this way they get classified as long term waiters, and
  35 don't get counted as running for purposes of load average calculation.
  36
  37 This is intended as a minimal fix.  In the longer term, it'd probably
  38 make sense to replace the semaphores with completions or something,
  39 and to do away with some of these StudlyCapped wrapper functions.
  40
  41 Signed-off-by: Jason Uhlenkott <jasonuhl@jasonuhl.org>
  42 --
  43
  44 This is untested, but what could possibly go wrong?  ;)
  45 ---
  46  include/linux/sdio/ctsystem_linux.h |    2 +-
  47  1 files changed, 1 insertions(+), 1 deletions(-)
  48
  49 diff --git a/include/linux/sdio/ctsystem_linux.h b/include/linux/sdio/ctsystem_linux.h
  50 index 0de89a6..c9e44f2 100644
  51 --- a/include/linux/sdio/ctsystem_linux.h
  52 +++ b/include/linux/sdio/ctsystem_linux.h
  53 @@ -968,7 +968,7 @@ typedef struct _OSKERNEL_HELPER {
  54          }
  55
  56  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
  57 -#define SD_WAIT_FOR_WAKEUP(p)   SignalWait(&(p)->WakeSignal);
  58 +#define SD_WAIT_FOR_WAKEUP(p)   SignalWaitInterruptible(&(p)->WakeSignal);
  59
  60  #define CT_LE16_TO_CPU_ENDIAN(x) __le16_to_cpu(x)
  61  #define CT_LE32_TO_CPU_ENDIAN(x) __le32_to_cpu(x)
  62 --
  63 1.5.6.3
  64