Re: [PATCH] convert: avoid malloc of original file size

From: Jeff King <peff@peff.net>
Date: Mar 8, 2019, 02:52 UTC
Message-ID: <20190308025237.GA12304@sigill.intra.peff.net>
In-Reply-To: <xmqqa7i6kvgf.fsf@gitster-ct.c.googlers.com>

On Fri, Mar 08, 2019 at 10:26:24AM +0900, Junio C Hamano wrote:

Show 12 quoted lines

> Jeff King <peff@peff.net> writes:
> 
> > As discussed there, I do think this only solves half the problem, as the
> > smudge filter has the same issue in reverse. That's more complicated to
> > fix, and AFAIK nobody is working on it. But I don't think there's any
> > reason not to pick up this part in the meantime.
> 
> Yeah, I agree that the reverse direction shares the same issue.
> 
> I am not sure 0 is a good initial value in this direction, either;
> I'd rather clip to min(len, core.bigfilethreshold) or something like
> that, to avoid regressing the more normal use cases.

That was my initial thought, too, but Joey's benchmarks show that it doesn't seem to make a big difference either way. In his numbers it did get measurable for a 1GB file, but we'd still not use "hint == len" in that case (we'd probably do one or two doublings to get there).

I also think running a real (non-condensing) filter on a 1GB file is already a pretty unlikely corner case.

> But let's queue this and see what happens.

Sounds good to me.

-Peff