From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: git@vger•kernel.org
Subject: Re: [RFC/PATCH] pkt-line: allow writing of LARGE_PACKET_MAX buffers
Date: Tue, 09 Dec 2014 14:41:51 -0800 [thread overview]
Message-ID: <xmqqa92wla34.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <20141209180916.GA26873@peff.net> (Jeff King's message of "Tue, 9 Dec 2014 13:09:16 -0500")
Jeff King <peff@peff•net> writes:
> On Tue, Dec 09, 2014 at 12:49:58PM -0500, Jeff King wrote:
>
>> Another option would be to use a static strbuf. Then we're only wasting
>> heap, and even then only as much as we need (we'd still manually cap it
>> at LARGE_PACKET_MAX since that's what the protocol dictates). This would
>> also make packet_buf_write more efficient (right now it formats into a
>> static buffer, and then copies the result into a strbuf; probably not
>> measurably important, but silly nonetheless).
>
> Below is what that would look like. It's obviously a much more invasive
> change, but I think the result is nice.
Yes, indeed. Is there any reason why we shouldn't go with this
variant, other than "it touches a bit more lines" that I am not
seeing?
> Let's switch to using a strbuf, with a hard-limit of
> LARGE_PACKET_MAX (which is specified by the protocol). This
> matches the size of the readers, as of 74543a0 (pkt-line:
> provide a LARGE_PACKET_MAX static buffer, 2013-02-20).
> Versions of git older than that will complain about our
> large packets, but it's really no worse than the current
> behavior. Right now the sender barfs with "impossibly long
> line" trying to send the packet, and afterwards the reader
> will barf with "protocol error: bad line length %d", which
> is arguably better anyway.
Anything older than 1.8.3 is affected by this, but only when the
sending side has to send a large packet. It is between failing
because the sender cannot send a large packet and failing because
the receiver does not expect such a large packet to come, and either
way the whole operation will fail anyway, so there is no net loss.
next prev parent reply other threads:[~2014-12-09 22:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-09 17:49 [RFC/PATCH] pkt-line: allow writing of LARGE_PACKET_MAX buffers Jeff King
2014-12-09 18:09 ` Jeff King
2014-12-09 22:41 ` Junio C Hamano [this message]
2014-12-10 4:36 ` Michael Blume
2014-12-10 7:34 ` [PATCH v3] " Jeff King
2014-12-10 8:36 ` Eric Sunshine
2014-12-10 9:42 ` Eric Sunshine
2014-12-10 9:49 ` Eric Sunshine
2014-12-10 9:53 ` Jeff King
2014-12-10 10:39 ` [PATCH 0/3] convert read_packed_refs to use strbuf Jeff King
2014-12-10 10:40 ` [PATCH 1/3] read_packed_refs: use a strbuf for reading lines Jeff King
2014-12-10 10:40 ` [PATCH 2/3] read_packed_refs: pass strbuf to parse_ref_line Jeff King
2014-12-10 10:40 ` [PATCH 3/3] read_packed_refs: use skip_prefix instead of static array Jeff King
2014-12-10 17:43 ` [PATCH 0/3] convert read_packed_refs to use strbuf Junio C Hamano
2014-12-10 9:47 ` [PATCH v4] pkt-line: allow writing of LARGE_PACKET_MAX buffers Jeff King
2014-12-10 9:56 ` Eric Sunshine
2014-12-10 20:14 ` Eric Sunshine
2014-12-10 21:06 ` Jeff King
2014-12-09 19:58 ` [RFC/PATCH] " Johannes Sixt
2014-12-09 20:00 ` Jeff King
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