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    Subject[RT] scheduling and oprofile
    I've been trying to use oprofile on an RT kernel to look at some
    performance issues. While running I notice the following sent to
    the console:

    BUG: scheduling with irqs disabled: java/0x00000000/4521
    caller is rt_mutex_slowlock+0x156/0x1dd
    [<c032051a>] schedule+0x65/0xd2 (8)
    [<c0321338>] rt_mutex_slowlock+0x156/0x1dd (12)
    [<c032142a>] rt_mutex_lock+0x24/0x28 (72)
    [<c0134904>] rt_down_read+0x38/0x3b (20)
    [<c0322a89>] do_page_fault+0xe3/0x52d (12)
    [<c03229a6>] do_page_fault+0x0/0x52d (76)
    [<c01033bb>] error_code+0x4f/0x54 (8)
    [<c01ce6d0>] __copy_from_user_ll+0x55/0x7c (44)
    [<f89be7ef>] dump_user_backtrace+0x2e/0x56 [oprofile] (24)
    [<c0134869>] rt_up_read+0x3e/0x41 (20)
    [<f89be864>] x86_backtrace+0x4a/0x5a [oprofile] (20)
    [<f89bd53a>] oprofile_add_sample+0x73/0x89 [oprofile] (20)
    [<f89beea3>] athlon_check_ctrs+0x22/0x4a [oprofile] (32)
    [<f89be8c5>] nmi_callback+0x18/0x1b [oprofile] (28)
    [<c01041ff>] do_nmi+0x24/0x33 (12)
    [<c0103462>] nmi_stack_correct+0x1d/0x22 (16)

    It seems strange to me that oprofile would be calling
    '__copy_from_user_ll' in this context. I can see why the
    changes made for RT locking expose this. But, doesn't this
    issue also exist on non-RT (default) kernels? What happens
    when we generate a page fault in this context on non-RT kernels?

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      Last update: 2006-10-23 23:25    [W:0.024 / U:38.148 seconds]
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