From: Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org>
To: GCC Patches <gcc-patches@gcc.gnu.org>
Cc: Mike Stump <mikestump@comcast.net>
Subject: Re: [PATCH] Fix detection of setrlimit in libstdc++ testsuite
Date: Thu, 10 Dec 2015 13:48:00 -0000 [thread overview]
Message-ID: <9B4A743A-A0A2-4B3F-8564-36685071C1C8@linaro.org> (raw)
In-Reply-To: <28F74808-E037-4192-BB5E-A0492BE31172@linaro.org>
> On Nov 11, 2015, at 7:56 PM, Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org> wrote:
>
> Hi,
>
> This patch fixes an obscure cross-testing problem that crashed (OOMed) our boards at Linaro. Several tests in libstdc++ (e.g., [1]) limit themselves to some reasonable amount of RAM and then try to allocate 32 gigs. Unfortunately, the configure test that checks presence of setrlimit is rather strange: if target is native, then try compile file with call to setrlimit -- if compilation succeeds, then use setrlimit, otherwise, ignore setrlimit. The strange part is that the compilation check is done only for native targets, as if cross-toolchains can't generate working executables. [This is rather odd, and I might be missing some underlaying caveat.]
>
> Therefore, when testing a cross toolchain, the test [1] still tries to allocate 32GB of RAM with no setrlimit restrictions. On most targets that people use for cross-testing this is not an issue because either
> - the target is 32-bit, so there is no 32GB user-space to speak of, or
> - the target board has small amount of RAM and no swap, so allocation immediately fails, or
> - the target board has plenty of RAM, so allocating 32GB is not an issue.
>
> However, if one is testing on a 64-bit board with 16GB or RAM and 16GB of swap, then one gets into an obscure near-OOM swapping condition. This is exactly the case with cross-testing aarch64-linux-gnu toolchains on APM Mustang.
>
> The attached patch removes "native" restriction from configure test for setrlimit. This enables setrlimit restrictions on the testsuite, and the test [1] expectedly fails to allocate 32GB due to setrlimit restriction.
>
> I have tested it on x86_64-linux-gnu and i686-linux-gnu native toolchains, and aarch64-linux-gnu and arm-linux-gnueabi[hf] cross-toolchains with no regressions [*].
>
> OK to commit?
>
> I didn't go as far as enabling setenv/locale tests when cross-testing libstdc++ because I remember of issues with generating locales in cross-built glibc. In any case, locale tests are unlikely to OOM the test board the way that absence of setrlimit does.
>
> [1] 27_io/ios_base/storage/2.cc
>
> [*] Cross-testing using user-mode QEMU made 27_io/fpos/14775.cc execution test to FAIL. This test uses setrlimit set max file size, and is misbehaving only under QEMU. I believe this a QEMU issue with not handling setrlimit correctly.
>
Ping.
--
Maxim Kuvyrkov
www.linaro.org
next prev parent reply other threads:[~2015-12-10 13:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-11 16:56 Maxim Kuvyrkov
2015-12-10 13:48 ` Maxim Kuvyrkov [this message]
2016-03-02 10:08 ` Maxim Kuvyrkov
2016-03-02 17:38 ` Mike Stump
2016-03-04 15:27 ` Jonathan Wakely
2016-04-05 11:20 ` Jonathan Wakely
2016-08-31 11:22 ` Maxim Kuvyrkov
2016-08-31 13:23 ` Jonathan Wakely
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