Date: Mon, 24 Sep 2007 11:37:31 +0200 From: "Attilio Rao" <attilio@freebsd.org> To: "Jung-uk Kim" <jkim@freebsd.org> Cc: freebsd-acpi@freebsd.org, freebsd-current@freebsd.org Subject: Re: [PATCH] OsdSynch.c modernization Message-ID: <3bbf2fe10709240237u790de351wddb81b0c511d7435@mail.gmail.com> In-Reply-To: <200709211827.29763.jkim@FreeBSD.org> References: <200709181516.11207.jkim@FreeBSD.org> <200709211715.17940.jhb@freebsd.org> <200709211827.29763.jkim@FreeBSD.org>
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2007/9/22, Jung-uk Kim <jkim@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 UMA uses its own internal locking scheme which includes blocking mutexes so you cannot maintain a spinlock over its functions. You can however use a blocking mutex instead than a sx lock, that with the help of adaptive spinning emulates a lot better spinlocks behaviour. Attilio -- Peace can only be achieved by understanding - A. Einstein
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