is vfs.lookup_shared unsafe in 7.3?

[cronfy]

>> Hello,
>>
>> Trying to overtake high server load (sudden peaks of 15%us/85%sy, LA >
>> 40, very slow lstat() at these moments, looks like some kind of lock
>> contention) I enabled vfs.lookup_shared=1 on two servers today. One is
>> FreeBSD-7.3 kernel csup'ed and built Sep  9 2010 and other is
>> FreeBSD-7.3 csup'ed and built Jul 16 2010.
>>
>> The server with more fresh kernel is running nice and does not show
>> high load anymore. But on the second server it did not help. More,
>> after a few hours of work with vfs.lookup_shared=1 I noticed processes
>> stucked in "ufs" state. I tried to kill them with no luck. Disabling
>> vfs.lookup_shared freezed the whole system.
>>
>> So, is vfs.lookup_shared=1 unsafe in 7.3? Did it become more stable
>> between 16 Jul and 9 Sep (is it the reason why first system is still
>> running?), or should I expect that it will freeze in a near time too?
>>
>> Thanks in advance!
>
> No, 7.3 has a bug that can cause these hangs that is probably made worse by
> vfs.lookup_shared=1, but can occur even if it is disabled.  You want
> these fixes applied (in order, one of them reverts part of another):

Thank you for the fix and for the explanation, that's exactly what I
wanted to know. Just to be sure: do these patches completely fix the
bug with hangs (even without vfs.lookup_shared=1)?

-- 
// cronfy