Re: [patch] voluntary-preempt-2.6.8.1-P9

[K.R. Foley]

Any idea what is going on here?

dmesg gives me this:


(kswapd0/32): new 305 us maximum-latency critical section.
 => started at: <get_swap_page+0x28/0x280>
 => ended at:   <get_swap_page+0x96/0x280>
 [<c0135dbf>] check_preempt_timing+0x19f/0x240
 [<c0151bf6>] get_swap_page+0x96/0x280
 [<c0151bf6>] get_swap_page+0x96/0x280
 [<c0135f88>] sub_preempt_count+0x48/0x60
 [<c0135f88>] sub_preempt_count+0x48/0x60
 [<c0151bf6>] get_swap_page+0x96/0x280
 [<c015155a>] add_to_swap+0x2a/0xd0
 [<c0142a73>] shrink_list+0x4e3/0x530
 [<c01413a6>] lru_add_drain+0x36/0x70
 [<c0135f88>] sub_preempt_count+0x48/0x60
 [<c0142bc2>] shrink_cache+0x102/0x370
 [<c0135f88>] sub_preempt_count+0x48/0x60
 [<c0142c26>] shrink_cache+0x166/0x370
 [<c014345e>] shrink_zone+0xae/0xe0
 [<c0143871>] balance_pgdat+0x1e1/0x250
 [<c01439a5>] kswapd+0xc5/0xe0
 [<c0117cc0>] autoremove_wake_function+0x0/0x60
 [<c0106336>] ret_from_fork+0x6/0x14
 [<c0117cc0>] autoremove_wake_function+0x0/0x60
 [<c01438e0>] kswapd+0x0/0xe0
 [<c0104505>] kernel_thread_helper+0x5/0x10


The trace actually looks like this:

preemption latency trace v1.0.2
-------------------------------
 latency: 305 us, entries: 2 (2)
    -----------------
    | task: kswapd0/32, uid:0 nice:0 policy:0 rt_prio:0
    -----------------
 => started at: get_swap_page+0x28/0x280
 => ended at:   get_swap_page+0x96/0x280
=======>
00000001 0.000ms (+0.000ms): get_swap_page (add_to_swap)
00000001 0.306ms (+0.306ms): sub_preempt_count (get_swap_page)

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