Re: [patch] preempt-timing-on-2.6.8-rc2-O2

Lee Revell
2004-08-08T04:21:20Z

On Sat, 2004-08-07 at 22:48, William Lee Irwin III wrote:

> It's probably actually a false positive. What I was explaining was why,
> if it were in fact a non-preemptible critical section, it wouldn't cause
> xruns.
>

These two seem to be real. It looks like get_user_pages is still
problematic in 2.6.8-rc2.

(jackd/6219): 10943us non-preemptible critical section violated 1000 us preempt threshold starting at kmap_atomic+0x10/0x60 and ending at kunmap_atomic+0x8/0x20
[<c0106717>] dump_stack+0x17/0x20
[<c0113eec>] dec_preempt_count+0x3c/0x50
[<c0111ce8>] kunmap_atomic+0x8/0x20
[<c013e2cb>] do_anonymous_page+0x8b/0x190
[<c013e41e>] do_no_page+0x4e/0x310
[<c013e8a1>] handle_mm_fault+0xc1/0x170
[<c013d280>] get_user_pages+0x110/0x380
[<c013e9f8>] make_pages_present+0x68/0x90
[<c0140196>] do_mmap_pgoff+0x3e6/0x620
[<c010b656>] sys_mmap2+0x76/0xb0
[<c01060b7>] syscall_call+0x7/0xb
ALSA /home/rlrevell/cvs/alsa/alsa-driver/alsa-kernel/core/pcm_lib.c:139: XRUN: pcmC0D2c
[<c0106717>] dump_stack+0x17/0x20
[<de93d64b>] snd_pcm_period_elapsed+0x27b/0x3e0 [snd_pcm]
[<de9791d1>] snd_emu10k1_interrupt+0xd1/0x3c0 [snd_emu10k1]
[<c011a7d3>] generic_handle_IRQ_event+0x33/0x60
[<c01079c2>] do_IRQ+0xb2/0x180
[<c01062d8>] common_interrupt+0x18/0x20
[<c0113e18>] __touch_preempt_timing+0x8/0x20
[<c0113ea2>] inc_preempt_count+0x32/0x40
[<c014cb8e>] fget+0x1e/0x60
[<c015ecdd>] do_pollfd+0x2d/0xa0
[<c015edaf>] do_poll+0x5f/0xc0
[<c015ef41>] sys_poll+0x131/0x220
[<c01060b7>] syscall_call+0x7/0xb
(gnome-terminal/914): 10738us non-preemptible critical section violated 1000 us preempt threshold starting at fget+0x1e/0x60 and ending at fget+0x3d/0x60
[<c0106717>] dump_stack+0x17/0x20
[<c0113eec>] dec_preempt_count+0x3c/0x50
[<c014cbad>] fget+0x3d/0x60
[<c015ecdd>] do_pollfd+0x2d/0xa0
[<c015edaf>] do_poll+0x5f/0xc0
[<c015ef41>] sys_poll+0x131/0x220
[<c01060b7>] syscall_call+0x7/0xb

Lee