Giant lock gone? (was: Re: ...focus, longevity, and lifecycle)

[Greg 'groggy' Lehey]

On Wednesday, 18 January 2012 at 19:58:19 -0500, Dieter BSD wrote:
>> The original goal for 5.0 was to completely remove the Giant lock (and
>> do other cool SMP-related stuff). Eventually it was realized that this
>> was too big a goal to fully accomplish in 5.0 (albeit too late in the
>> process) and the goal was changed to do the basic framework for the new
>> SMP model; and lay the groundwork for "some things run under Giant for
>> now, and we'll remove it from them ASAP." That actually turned out to
>> last through 6, making 7 the realization of what 5.0 was supposed to be.
>
> So you are saying that the Giant lock was completely removed in 7.0?

Giant is still there in 9.0.

It's a pity you didn't say who you were quoting there.  To my
knowledge we never intended to completely remove Giant in 5.x.  We
realised from the start that it would take a long time.  See
http://www.lemis.com/grog/diary-jun2000.php for what we decided 12
years ago.  Point 6 suggests removing the "Giant Kernel Spinlock", but
that is misleading.  We did that, and we gave the name Giant to the
"blocking mutex for the kernel".  Previously Giant didn't have a name,
because it was the only one.

Greg
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