Re: [PATCH] handle concurrent pruning of packed objects

From: Junio C Hamano <junkio@cox.net>
Date: Jun 2, 2006, 16:10 UTC
Message-ID: <7vk67zbksv.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <20060602160456.GA8957@coredump.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 9 quoted lines

> That shouldn't make a difference for correctness, even if the old packs
> are still there. If you have an object in two packs, then it doesn't
> matter which one you pull it from. The main impacts I can think of are:
>   1. The old pack may already be mapped, and it would be more efficient
>      to use it. However, the new pack will be mapped on first use, so it
>      will be used from then on.
>   2. The pack list can grow without bound. However, for this to matter,
>      you'd have to do many prunes during the course of a single git
>      command.

I agree 100% on "shouldn't" part. What I wonder is if everybody works correctly if we mmap the same file (all available .idx are mapped all the time, and we map .pack LRU) twice. But I realize we have NO_MMAP configuration for unfortunate platforms to work it around so that wouldn't be a big deal.