Re: [PATCH] gc: run pre-detach operations under lock

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 12, 2017, 16:46 UTC
Message-ID: <xmqqvamx1u3i.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20170711090635.swowex7yry7kqb7v@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 6 quoted lines

> Instead, we can do something a bit simpler: take the lock
> only for the duration of the pre-detach work, then detach,
> then take it again for the post-detach work. Technically,
> this means that the post-detach lock could lose to another
> process doing pre-detach work. But in the long run this
> works out.

You might have found this part gross, but I actually don't. It looks like a reasonable practical compromise, and I tried to think of a scenario that this would do a wrong thing but I didn't---it is not like we carry information off-disk from the pre-detach to post-detach work to cause the latter make decisions on it, so this "split into two phrases" looks fairly safe.