Re: require_ulimit_v_(): tests skipped with enable-single-binary

[Dmitry V. Levin]

On Thu, Oct 08, 2015 at 03:17:58AM +0300, Dmitry V. Levin wrote:
> On Tue, Sep 22, 2015 at 03:13:54AM +0200, Bernhard Voelker wrote:
> > On 09/21/2015 02:56 AM, Pádraig Brady wrote:
> > > On 21/09/15 00:47, Bernhard Voelker wrote:
> > >> >From 1335ab2713aab020564275c49fdb3e92bb9a207b Mon Sep 17 00:00:00 2001
> > >> From: Bernhard Voelker <m...@bernhard-voelker.de>
> > >> Date: Mon, 21 Sep 2015 01:40:33 +0200
> > >> Subject: [PATCH] maint: use adaptive approach for `ulimit -v` based tests
> > >>
> > >> When configured with either 'symlinks' or 'shebangs' as value for
> > >> the --enable-single-binary option, tests based on `ulimit -v` are
> > >> skipped.  The reason is that the multicall 'coreutils' binary requires
> > >> much more memory due to shared libraries being loaded, and the size of
> > >> the 'date' binary (~290KiB) compared to the multicall binary (~5MiB),
> > >> of course.  Finally, in the case of 'shebangs', the starting shell
> > >> requires more memory, too
> > >>
> > >> Instead of using hard-coded values for the memory limit, use an
> > >> adaptive approach: first determine the amount of memory for a similar,
> > >> yet more trivial command, and then do the real test run using that
> > > 
> > > s/command/invocation of the command/
> > > 
> > > I can't find any significant issues with the patch at all.
> > 
> > Thanks, I'll push with that change tomorrow.
> 
> This approach is very fragile.  It actually failed tests/misc/head-c
> on an x86 box with the following diagnostics:
> 
> 
> $ (ulimit -v 2048 && src/head -c1 < /dev/null; echo $?)
> 0
> $ (ulimit -v 2048 && src/head --bytes=-2147483647 < /dev/null; echo $?)
> src/head: memory exhausted
> 1
> $ (ulimit -v $((2048+128)) && src/head --bytes=-2147483647 < /dev/null; echo 
> $?)
> 0

I've ended up with the following workaround:

diff --git a/init.cfg b/init.cfg
index f71f94c..b199302 100644
--- a/init.cfg
+++ b/init.cfg
@@ -156,7 +156,7 @@ get_min_ulimit_v_()
       prev_v=$v
       for v in $( seq $(($prev_v-1000)) -1000 1000 ); do
         ( ulimit -v $v && "$@" ) >/dev/null \
-          || { echo $prev_v; return 0; }
+          || { echo $(($prev_v+256)); return 0; }
         prev_v=$v
       done
     fi


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