From: Ivan Kanis <expire-by-2010-08-11@kanis.fr>
To: Nguyen Thai Ngoc Duy <pclouds@gmail.com>, jaredhance@gmail.com
Cc: Avery Pennarun <apenwarr@gmail.com>,
jnareb@gmail.com, git <git@vger.kernel.org>
Subject: Re: Git server eats all memory
Date: Fri, 06 Aug 2010 19:23:17 +0200 [thread overview]
Message-ID: <87hbj74pve.fsf@kanis.fr> (raw)
In-Reply-To: <AANLkTi=tf51FWkZZFw9cF=pcCyadgp7a9EXK=KQ6GSQS@mail.gmail.com> (Nguyen Thai Ngoc Duy's message of "Fri, 6 Aug 2010 11:51:33 +1000")
Nguyen Thai Ngoc Duy <pclouds@gmail.com> wrote:
> Naah, git pack-objects needs list of commit tips. Try
> git for-each-ref|cut -c 1-40|git pack-objects --all --stdout > /dev/null
Jared Hance <jaredhance@gmail.com> wrote:
> I would look in the code for malloc calls that don't have a free call,
> or spots where free calls might not be hit.
Hello Jared and Nguyen,
Thank you Nguyen for your command. I can now reproduce the problem
without needing the network. I have been following Jared lead today on
a potential memory leak. Here is what I found out.
I downloaded the latest release of git 1.7.2.1 and compiled it with
debugging support. I ran valgrind on the command and found two memory
leaks. I put the output at the bottom of the e-mail as it's not very
interesting. I patched one of the leak in pack_objects.c but got the
same problem: over 4G of memory consumption for a 4G repository.
I've come to the conclusion that it's not a memory leak.
This afternoon I put macro around the following functions: xmalloc
xmallocz, xrealloc, xcalloc and xmmap. It reported the line of code and
size passed in each functions. I then run the result through a script
that totaled the amount used by each bit of code.
Here are the top 3 consumers:
| function | source | size in M |
|----------+----------------------------+-----------|
| xrealloc | builtin/pack-objects.c:690 | 86 |
| xmallocz | patch-delta.c:36 | 301 |
| xmmap | sha1_file.c:772 | 4393 |
I expected the malloc to take 4G but was surprised it didn't. It seems
to be mmap taking all the memory. I am not familiar with that function,
it looks like it's mapping memory to a file... Is it reasonable to mmap
so much memory?
Today I chatted with someone on freenode #git and he reported the same
problem on his 2G repository, I am glad I am not the only one seeing
this ;)
I tried reading the code but it's going over my head. I'll look at is
some more next monday.
If anyone is familiar with the code source of git I would love to have
some insight into this.
Take care,
Ivan Kanis
PS: output of valgrind --leak-check=full
65 bytes in 1 blocks are definitely lost in loss record 4 of 7
at 0x4C2260E: malloc (vg_replace_malloc.c:207)
by 0x4C22797: realloc (vg_replace_malloc.c:429)
by 0x4C600D: xrealloc (wrapper.c:80)
by 0x4B7939: strbuf_grow (strbuf.c:70)
by 0x4B80BA: strbuf_addf (strbuf.c:201)
by 0x4832EF: system_path (exec_cmd.c:37)
by 0x483411: setup_path (exec_cmd.c:104)
by 0x404AF2: main (git.c:536)
512 bytes in 1 blocks are definitely lost in loss record 5 of 8
at 0x4C203E4: calloc (vg_replace_malloc.c:397)
by 0x4C5F9D: xcalloc (wrapper.c:96)
by 0x445741: cmd_pack_objects (pack-objects.c:2117)
by 0x4048EE: handle_internal_command (git.c:270)
by 0x404B03: main (git.c:470)
--
http://kanis.fr
Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
next prev parent reply other threads:[~2010-08-06 17:23 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-04 14:57 Git server eats all memory Ivan Kanis
2010-08-04 15:55 ` Matthieu Moy
2010-08-04 17:50 ` Ivan Kanis
2010-08-04 20:12 ` Avery Pennarun
2010-08-05 6:33 ` Ivan Kanis
2010-08-05 22:45 ` Jared Hance
2010-08-06 1:37 ` Nguyen Thai Ngoc Duy
2010-08-06 1:51 ` Nguyen Thai Ngoc Duy
2010-08-06 11:34 ` Jakub Narebski
2010-08-06 17:23 ` Ivan Kanis [this message]
2010-08-07 6:42 ` Dmitry Potapov
2010-08-09 10:12 ` Excessive mmap [was Git server eats all memory] Ivan Kanis
2010-08-09 12:35 ` Dmitry Potapov
2010-08-09 16:34 ` Ivan Kanis
2010-08-09 16:50 ` Avery Pennarun
2010-08-09 17:45 ` Tomas Carnecky
2010-08-09 18:17 ` Avery Pennarun
2010-08-09 21:28 ` Dmitry Potapov
2010-08-11 15:47 ` Ivan Kanis
2010-08-11 16:35 ` Avery Pennarun
[not found] ` <wes4oetv31i.fsf@kanis.fr>
2010-08-17 17:07 ` Dmitry Potapov
2018-06-20 14:53 ` Duy Nguyen
[not found] ` <AANLkTi=yeTh2tKn9t_=iZbdB5VLrfCPZ2_fBpYdf9wta@mail.gmail.com>
[not found] ` <wesbp9cnnag.fsf@kanis.fr>
2010-08-09 9:57 ` Git server eats all memory Nguyen Thai Ngoc Duy
2010-08-09 17:38 ` Ivan Kanis
2010-08-10 0:46 ` Robin H. Johnson
2010-08-10 2:31 ` Sverre Rabbelier
2010-08-11 10:30 ` Sam Vilain
2010-08-11 15:54 ` Ivan Kanis
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