[PATCH] OsdSynch.c modernization
John Baldwin
jhb at freebsd.org
Mon Sep 24 09:13:25 PDT 2007
2007/9/22, Jung-uk Kim <jkim at freebsd.org>:
> I thought exactly the same when I started rewriting it (almost half
> year ago!). I have tried all of the above, spent numerous sleepless
> nights, and miserably failed. :-(
>
> Spin mutex is too restrictive (e.g., it cannot be used with other
> locks gracefully). critical_enter() causes:
>
> panic: blockable sleep lock (sleep mutex) 32 @
> /usr/src/sys/vm/uma_core.c:1830 cpuid = 0
> KDB: enter: panic
> [thread pid 21 tid 100013 ]
> Stopped at kdb_enter+0x32: leave
However, disabling interrupts while you block on other locks is just as bad,
we just don't assert for it. Better would be to fix ACPI-CA to not try to
malloc() while holding a spin lock. You should be able to see where it is
doing that via the stack trace. If the malloc is using M_NOWAIT you will be
far better off using a plain mutex and just not disabling interrupts.
--
John Baldwin
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