From: Jeff King <peff@peff.net>
To: Dennis Kaarsemaker <dennis@kaarsemaker.net>
Cc: Konstantin Ryabitsev <konstantin@linuxfoundation.org>,
git@vger.kernel.org
Subject: Re: [PATCH 0/2] fix http deadlock on giant ref negotiations
Date: Fri, 15 May 2015 04:38:43 -0400 [thread overview]
Message-ID: <20150515083843.GA16910@peff.net> (raw)
In-Reply-To: <1431675680.14042.39.camel@kaarsemaker.net>
On Fri, May 15, 2015 at 09:41:20AM +0200, Dennis Kaarsemaker wrote:
> > I have no clue how to write a test that would trigger this reliably
> > without requiring a gigantic test fixture. However, I did confirm that
> > it fixes the problem on the chromium case you provided (which otherwise
> > deadlocks reliably for me).
>
> This looks similar to the failure I posted about alst year in
> http://thread.gmane.org/gmane.comp.version-control.git/258514
>
> Though the issue is different, it has the same 'hanging git fetch'
> symptom due to the deadlock between upload-pack and http-backend.
Thanks, I think it is the same issue (in the end I was replicating not
with `--reference`, but just by doing a fetch from the other
repository). And our solutions are essentially the same. I do prefer
mine because:
1. It keeps the buffering logic in http-backend; the half-duplex
nature is an http detail.
2. I think it's better to buffer the request rather than the response,
for the reasons I stated in the commit message.
> The patch I sent back then is suboptimal, as it can cause larger packs
> than necessary (we still use it though, as the alternative is a
> non-working git), but it does include a test you may be able to use to
> verify your fix, if this is indeed the same issue.
I applied the test from your patch, but couldn't get it to fail even
with stock git. The test above it shrunk a bit, but I was able to tweak
yours to generate tags from 2001..100000, which I thought would have
worked. I suspect it's something silly like the size not being quite
big enough for the pipe buffer on my system, or something like that.
Though I couldn't get it to fail even with 200,000 tags, so perhaps it's
something else.
-Peff
next prev parent reply other threads:[~2015-05-15 8:38 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-13 21:04 Clone hangs when done over http with --reference Konstantin Ryabitsev
2015-05-14 0:47 ` Jeff King
2015-05-14 1:02 ` [PATCH] http-backend: fix die recursion with custom handler Jeff King
2015-05-15 6:20 ` Jeff King
2015-05-14 17:08 ` Clone hangs when done over http with --reference Konstantin Ryabitsev
2015-05-14 19:52 ` Jeff King
2015-05-15 6:29 ` [PATCH 0/2] fix http deadlock on giant ref negotiations Jeff King
2015-05-15 6:29 ` [PATCH 1/2] http-backend: fix die recursion with custom handler Jeff King
2015-05-15 6:33 ` [PATCH 2/2] http-backend: spool ref negotiation requests to buffer Jeff King
2015-05-15 18:22 ` Junio C Hamano
2015-05-15 18:28 ` Konstantin Ryabitsev
2015-05-20 7:35 ` [PATCH v2 0/3] fix http deadlock on giant ref negotiations Jeff King
2015-05-20 7:36 ` [PATCH v2 1/3] http-backend: fix die recursion with custom handler Jeff King
2015-05-20 7:36 ` [PATCH v2 2/3] t5551: factor out tag creation Jeff King
2015-05-20 7:37 ` [PATCH v2 3/3] http-backend: spool ref negotiation requests to buffer Jeff King
2015-05-26 2:07 ` Konstantin Ryabitsev
2015-05-26 2:24 ` Jeff King
2015-05-26 3:43 ` Junio C Hamano
2015-05-15 19:16 ` [PATCH 2/2] " Jeff King
2015-05-15 7:41 ` [PATCH 0/2] fix http deadlock on giant ref negotiations Dennis Kaarsemaker
2015-05-15 8:38 ` Jeff King [this message]
2015-05-15 8:44 ` Dennis Kaarsemaker
2015-05-15 8:53 ` Jeff King
2015-05-15 9:11 ` Dennis Kaarsemaker
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