Re: git-revert is a memory hog

From: Jeff King <peff@peff.net>
Date: Jan 29, 2008, 22:54 UTC
Message-ID: <20080129225428.GC4586@coredump.intra.peff.net>
In-Reply-To: <alpine.LFD.1.00.0801300945310.3378@www.l.google.com>

On Wed, Jan 30, 2008 at 09:49:44AM +1100, Linus Torvalds wrote:

Show 6 quoted lines

> But  the
> 
>         if (rename_limit <= 0 || rename_limit > 32767)
>                 rename_limit = 32767;
> 
> which is there purely to avoid overflow in 32-bit multiplication should

Ah, right, that first conditional handles the overflow. Then what is the second one doing? If they are both larger than the rename limit, then won't there square by definition be larger than the square of the rename limit? I.e., can't we just get rid of the second conditional?

> Or, better yet (which was what I was hoping for originally), we'd just 
> make the inexact rename detection be linear-size/time rather than O(m*n). 
> But those patches never really came together, so we do need to limit it 
> more aggressively.

I had trouble getting the memory usage to a reasonable level. The hash tables were just getting enormous.

-Peff