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Date: Sat, 25 Nov 2000 12:32:16 -0800 (PST)
Organization: BSD, Inc.
From: John Baldwin <jhb@FreeBSD.ORG>
To: Jake Burkholder <jburkhol@home.com>
Subject: Re: uidinfo patches, review please.
Cc: smp@FreeBSD.ORG, Alfred Perlstein <bright@wintelcom.net>
Sender: owner-freebsd-smp@FreeBSD.ORG
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X-Loop: FreeBSD.org
On 25-Nov-00 Jake Burkholder wrote:
>>
>> On 25-Nov-00 Alfred Perlstein wrote:
>> > Protect the uidinfo structures.
>> >
>> > My only concern is that I must now include sys/mutex.h in
>> > sys/resourcevar.h, I didn't notice any userland utils using
>> > this file, I'm going to try to do a buildworld.
>> >
>> > A kernel with this patch boots and seems to run multiuser
>> > fine.
>
> Looks ok to me.
>
>>
>> I'll try and test this on Monday. Have you compiled a kernel with WITNESS
>> turned on? You probably want to add an explicit lock order of:
>>
>> "uidinfo hash", "uidinfo struct", NULL
>>
>> to the order_list in the witness code to make sure those locks aren't gotten
>> out of order as well. Looks ok to me though for the most part (see comments
>
> Kernel boots with WITNESS enabled, I also added this to the order list;
> make buildworld is chugging away on my SMP box.
Cool.
>> > @@ -735,9 +744,13 @@
>> > printf("freeing uidinfo: uid = %d, proccnt = %ld\n",
>> > uip->ui_uid, uip->ui_proccnt);
>> > LIST_REMOVE(uip, ui_hash);
>> > + mtx_destroy(&uip->ui_mtx);
>> > + mtx_exit(&uidhash_mtx, MTX_DEF);
>>
>> You should mtx_exit(&uip->ui_mtx) before destroying it here.
>
> This isn't strictly necessary, mtx_destroy handles destroying a
> held mutex. I suppose it saves a locked bus op.
Well, I'd rather have it for correctness' sake.
--
John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/
PGP Key: http://www.Baldwin.cx/~john/pgpkey.asc
"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
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