Re: git-revert is a memory hog

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 29, 2008, 22:36 UTC
Message-ID: <7vfxwgmf87.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <20080129222007.GA3985@coredump.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 10 quoted lines

> On Wed, Jan 30, 2008 at 08:51:09AM +1100, Linus Torvalds wrote:
>
>> I definitely can reproduce it, it's horrid.
>> 
>> This is from "top" fairly late in the game, but with the thing not even 
>> done yet. Current git, pretty much fully (and fairly aggressively) packed 
>> current kernel repo, and using "diff.renamelmit=0".
>
> Hrm, setting diff.renamelimit to 0 lets me reproduce (I thought I tried
> it before, but clearly not...).

Hmph. But I wonder why this part does not trigger, even when you have renamelimit set to 0.

	/*
	 * This basically does a test for the rename matrix not
	 * growing larger than a "rename_limit" square matrix, ie:
	 *
	 *    rename_dst_nr * rename_src_nr > rename_limit * rename_limit
	 *
	 * but handles the potential overflow case specially (and we
	 * assume at least 32-bit integers)
	 */
	if (rename_limit <= 0 || rename_limit > 32767)
		rename_limit = 32767;
	if (rename_dst_nr > rename_limit && rename_src_nr > rename_limit)
		goto cleanup;
	if (rename_dst_nr * rename_src_nr > rename_limit * rename_limit)
		goto cleanup;

I wonder if the second one for the overflow avoidance should be using || instead of &&, though.