[PATCH] 8170639: [Linux] jsig is limited to a maximum of 64 signals
Ao Qi
aoqi at loongson.cn
Tue Mar 5 10:25:51 UTC 2019
Hi David,
Webrev: http://cr.openjdk.java.net/~aoqi/8170639/webrev.03
What about this version? Am I understanding correctly? I think this
version is indeed much better. I also fixed a problem in my previous
version:( The code was only put into #ifdef SUPPORTS_CLOCK_MONOTONIC
block.
Done tests:
build: linux-x86_64-{server, minimal, zero}-{fastdebug, release},
solaris-x86_64-server-release
jtreg: linux-x86_64-server-release: hotspot:tier1
I am doing other tests. Seems good so far.
Thanks,
Ao Qi
On Tue, Mar 5, 2019 at 10:45 AM David Holmes <david.holmes at oracle.com> wrote:
>
> On 5/03/2019 12:22 pm, Ao Qi wrote:
> >
> >
> > David Holmes <david.holmes at oracle.com <mailto:david.holmes at oracle.com>>
> > 于2019年3月1日 周五下午12:18写道：
> >
> > Hi,
> >
> > On 28/02/2019 9:01 pm, Ao Qi wrote:
> > > Hi,
> > >
> > > This version is more consolidated than my first version in this
> > > thread: http://cr.openjdk.java.net/~aoqi/8170639/webrev.01/. I filed
> > > my first version here:
> > > http://cr.openjdk.java.net/~aoqi/8170639/webrev.00/
> > >
> > > I fixed the linux and bsd using sigset_t, so jsig is not limited to a
> > > maximum of 64 signals for linux and bsd. The logic of aix and solaris
> > > is not changed.
> >
> > Thanks for doing this. Overall this is a much better approach.
> >
> > I have two requests.
> >
> > There are too many ifdefs for solaris in the os_posix.cpp code. I
> > hadn't
> > realized the difference between Solaris and the other *NIX platforms in
> > this area (allowing for real-time signal chaining). Please restore the
> > Solaris code and put one ifndef solaris around the new code is
> > os_posix.[ch]pp.
> >
> >
> > Hi David,
> >
> > Thanks for your review and advice.
> >
> > I think the best way is to eliminate ifdefs for solaris, but as you said
> > in a previous email [1]: "SIGRTMAX is a macro not a constant so you
> > can't declare a static array using it. You would need to malloc the
> > array as done on Solaris." So I have to use ifdefs for solaris, I did
> > not find a way to eliminate it. I have used one ifndef solaris as you
> > request.
>
> What I was suggesting was to leave os_solaris.cpp alone completely for
> this change, and have the new os_posix.* functions defined in an
> "#ifndef SOLARIS" block.
>
> Thanks,
> David
>
> PS. I will be away for a few days after today.
>
> > There's no need for a separate os::posix::init_sigs() API, just do the
> > signal set initialization in os::posix::init_2();
> >
> >
> > I have done it.
> >
> > Webrev: http://cr.openjdk.java.net/~aoqi/8170639/webrev.02/
> >
> > Tested:
> > build tests
> > linux-x86_64-minimal-fastdebug
> > linux-x86_64-zero-fastdebug
> > linux-x86_64-server-fastdebug
> > linux-x86_64-minimal-release
> > linux-x86_64-zero-release
> > linux-x86_64-server-release
> > solaris-x86_64-server-release
> > solaris-x86_64-server-fastdebug
> > linux-mips64el-zero-release
> > linux-mips64el-zero-fastdebug
> >
> > jtreg tests
> > linux-x86_64-server-release: tier1,
> > hotspot-tier1(JAVA_OPTIONS=-XX:-UseSignalChaining),
> > hotspot-tier1(JAVA_OPTIONS=-XX:+AllowUserSignalHandlers)
> > solaris-x86_64-server-release: hotspot-tier1,
> > hotspot-tier1(JAVA_OPTIONS=-XX:-UseSignalChaining)
> >
> > Thanks,
> > Ao Qi
> >
> > [1]
> > https://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2018-March/027219.html
> >
> >
> > Thanks,
> > David
> > -----
> >
> > > The tests I did:
> > >
> > > build tests：
> > > linux-x86_64-server-release
> > > linux-x86_64-server-fastdebug
> > > linux-x86_64-zero-release
> > > linux-x86_64-zero-fastdebug
> > > linux-x86_64-minimal-release
> > > linux-x86_64-minimal-fastdebug
> > > solaris-x86_64-server-release
> > > solaris-x86_64-server-fastdebug
> > > linux-mips64el-zero-release
> > > linux-mips64el-zero-fastdebug
> > >
> > > jtreg tests：
> > > linux-x86_64-server-release: tier1, tier2, tier3
> > > linux-x86_64-server-fastdebug: tier1
> > > solaris-x86_64-server-release: hotspot-tier1
> > >
> > > No regression was found. Could you please review this version?
> > >
> > > On Fri, Jan 25, 2019 at 10:56 PM Magnus Ihse Bursie
> > > <magnus.ihse.bursie at oracle.com
> > <mailto:magnus.ihse.bursie at oracle.com>> wrote:
> > >>
> > >> On 2018-12-18 01:33, David Holmes wrote:
> > >>> On 18/12/2018 9:57 am, Ao Qi wrote:
> > >>>> Hi,
> > >>>>
> > >>>> On Tue, Dec 18, 2018 at 4:32 AM David Holmes
> > >>>> <david.holmes at oracle.com <mailto:david.holmes at oracle.com>> wrote:
> > >>>>>
> > >>>>> On 17/12/2018 9:48 pm, Ao Qi wrote:
> > >>>>>> Hi David Holmes,
> > >>>>>>
> > >>>>>> Thanks for your reply. It makes sense. Is it possible to create
> > >>>>>> another bug ID to fix the problem?
> > >>>>>
> > >>>>> I'd prefer to see this fixed properly than point fixed on
> > linux for an
> > >>>>> unsupported platform.
> > >>>>
> > >>>> I thought the problem is "[Linux] jsig is limited to a maximum
> > of 64
> > >>>> signals" and the patch was intended to fixed this problem. It just
> > >>>> didn't use "A better solution", but I think it is better than the
> > >>>> current situation.
> > >>>
> > >>> Better for you but I would prefer to see an overall better
> > solution.
> > >>> It really shouldn't be very difficult. Compare the AIX version with
> > >>> your improved Linux version, reconcile any differences, and
> > make it a
> > >>> shared posix version, then confirm it works on OS X and Solaris.
> > >>>
> > >>>> Is zero/mips (or all platforms having more than 64 signals) a
> > >>>> unsupported platform?
> > >>>
> > >>> Yes. We make allowances for Zero as it can support a vast range of
> > >>> platforms for which no native OpenJDK port exists (in the case
> > of MIPS
> > >>> that port seems inactive), but in general we don't go out of
> > our way
> > >>> to make changes in the main code that only benefit such platforms.
> > >>>
> > >>> I'm subtly trying to coerce you into making the change I'd like
> > to see
> > >>> here. ;-) I can assist with build/test on other POSIX platforms.
> > >> If you are going down that route, I recommend looking at
> > >> src/java.base/unix/native/libjsig/jsig.c for inspiration. It was
> > >> recently unified across all unix platforms we currently support,
> > so any
> > >> special treatment there for a specific platform (I think
> > solaris, macosx
> > >> and aix have some special stuff going on), is likely to apply to the
> > >> signal handling inside the VM as well. On the other hand, general
> > >> solutions that worked in jsig.c is likely to work as well in the VM.
> > >>
> > >
> > > Hi Magnus,
> > >
> > > Thanks for you information and advise. That is very helpful.
> > > Difference between hotspot/os/${os_name}/os_${os_name}.cpp is much
> > > more than the difference between ${os_name}/native/libjsig/jsig.c, so
> > > it is difficult to unify all the jsig related codes into os_posix.hpp
> > > and os_posix.cpp. Maybe I would try to do it in another issue.
> > >
> > > Cheers,
> > > Ao Qi
> > >
> > >> /Magnus
> > >>>
> > >>> Cheers,
> > >>> David
> > >>>
> > >>>> Cheers,
> > >>>> Ao Qi
> > >>>>>
> > >>>>> Thanks,
> > >>>>> David
> > >>>>>
> > >>>>>> Cheers,
> > >>>>>> Ao Qi
> > >>>>>>
> > >>>>>> On Mon, Dec 17, 2018 at 7:30 PM David Holmes
> > >>>>>> <david.holmes at oracle.com <mailto:david.holmes at oracle.com>>
> > wrote:
> > >>>>>>>
> > >>>>>>> Thanks for reminding me about the rest of the discussion. The
> > >>>>>>> point of
> > >>>>>>> the RFE I filed was to examine if we could get a
> > consolidated POSIX
> > >>>>>>> version using sigset_t. I'd rather see that than a point
> > fix for
> > >>>>>>> Linux.
> > >>>>>>>
> > >>>>>>> Thanks,
> > >>>>>>> David
> > >>>>>>>
> > >>>>>>> On 17/12/2018 6:50 pm, Ao Qi wrote:
> > >>>>>>>> Hi David Holmes,
> > >>>>>>>>
> > >>>>>>>> I am not sure what is the specific issue of "NSIG not being
> > >>>>>>>> defined".
> > >>>>>>>> Do you mean the issue mentioned in "but I found that NSIG was
> > >>>>>>>> missing
> > >>>>>>>> from signal.h on some architectures, mips being among
> > them"[1]? If
> > >>>>>>>> yes, James Cowgill answered this in [2]. I check it on
> > MIPS, NSIG is
> > >>>>>>>> defined in signal.h and it is 128.
> > >>>>>>>>
> > >>>>>>>> Cheers,
> > >>>>>>>> Ao Qi
> > >>>>>>>>
> > >>>>>>>> [1]
> > >>>>>>>>
> > http://mail.openjdk.java.net/pipermail/hotspot-dev/2016-November/025401.html
> > >>>>>>>> [2]
> > >>>>>>>>
> > http://mail.openjdk.java.net/pipermail/hotspot-dev/2016-December/025416.html
> > >>>>>>>>
> > >>>>>>>> On Mon, Dec 17, 2018 at 8:02 AM David Holmes
> > >>>>>>>> <david.holmes at oracle.com <mailto:david.holmes at oracle.com>>
> > wrote:
> > >>>>>>>>>
> > >>>>>>>>> Hi,
> > >>>>>>>>>
> > >>>>>>>>> Was the issue of NSIG not being defined resolved?
> > >>>>>>>>>
> > >>>>>>>>> Thanks,
> > >>>>>>>>> David
> > >>>>>>>>>
> > >>>>>>>>> On 14/12/2018 10:23 pm, Ao Qi wrote:
> > >>>>>>>>>> Hi all,
> > >>>>>>>>>>
> > >>>>>>>>>> Zero does not build on Linux MIPS (actually all Linux of
> > NSIG >
> > >>>>>>>>>> 64)
> > >>>>>>>>>> since OpenJDK 9, because NISG is 128 on MIPS and can not be
> > >>>>>>>>>> encoded in
> > >>>>>>>>>> uint64_t sigs. James Cowgill from Debian tried to push a
> > patch
> > >>>>>>>>>> fixing
> > >>>>>>>>>> this[1] but it seems he failed. I would like to try again to
> > >>>>>>>>>> request
> > >>>>>>>>>> fixing this in http://hg.openjdk.java.net/jdk/jdk. This was
> > >>>>>>>>>> fixed in
> > >>>>>>>>>> AIX implementation.
> > >>>>>>>>>>
> > >>>>>>>>>> After applying this patch, zero can be built on MIPS (Debian
> > >>>>>>>>>> testing).
> > >>>>>>>>>> I've run the jtreg tests [2] on x86 Linux.
> > >>>>>>>>>>
> > >>>>>>>>>> [1]
> > >>>>>>>>>>
> > http://mail.openjdk.java.net/pipermail/hotspot-dev/2016-November/025399.html
> > >>>>>>>>>> [2]
> > >>>>>>>>>>
> > https://download.java.net/openjdk/testresults/12/docs/howtoruntests.html
> > >>>>>>>>>>
> > >>>>>>>>>>
> > >>>>>>>>>> Cheers,
> > >>>>>>>>>> Ao Qi
> > >>>>>>>>>>
> > >>>>>>>>>> $ hg export -r 52869
> > >>>>>>>>>> # HG changeset patch
> > >>>>>>>>>> # User aoqi
> > >>>>>>>>>> # Date 1544089853 0
> > >>>>>>>>>> # Thu Dec 06 09:50:53 2018 +0000
> > >>>>>>>>>> # Node ID 3eea22b79dc3a4bf26616bde1acb587e3f56e6fe
> > >>>>>>>>>> # Parent b4982a22926b4ddf1a7b1f770e4d42ce8c1dd575
> > >>>>>>>>>> 8170639: [Linux] jsig is limited to a maximum of 64 signals
> > >>>>>>>>>>
> > >>>>>>>>>> diff -r b4982a22926b -r 3eea22b79dc3
> > >>>>>>>>>> src/hotspot/os/linux/os_linux.cpp
> > >>>>>>>>>> --- a/src/hotspot/os/linux/os_linux.cpp Thu Dec 06 11:54:39
> > >>>>>>>>>> 2018 +0530
> > >>>>>>>>>> +++ b/src/hotspot/os/linux/os_linux.cpp Thu Dec 06 09:50:53
> > >>>>>>>>>> 2018 +0000
> > >>>>>>>>>> @@ -4434,10 +4434,7 @@
> > >>>>>>>>>>
> > >>>>>>>>>> // For signal-chaining
> > >>>>>>>>>> struct sigaction sigact[NSIG];
> > >>>>>>>>>> -uint64_t sigs = 0;
> > >>>>>>>>>> -#if (64 < NSIG-1)
> > >>>>>>>>>> -#error "Not all signals can be encoded in sigs. Adapt
> > its type!"
> > >>>>>>>>>> -#endif
> > >>>>>>>>>> +sigset_t sigs;
> > >>>>>>>>>> bool os::Linux::libjsig_is_loaded = false;
> > >>>>>>>>>> typedef struct sigaction *(*get_signal_t)(int);
> > >>>>>>>>>> get_signal_t os::Linux::get_signal_action = NULL;
> > >>>>>>>>>> @@ -4516,7 +4513,7 @@
> > >>>>>>>>>> }
> > >>>>>>>>>>
> > >>>>>>>>>> struct sigaction*
> > os::Linux::get_preinstalled_handler(int
> > >>>>>>>>>> sig) {
> > >>>>>>>>>> - if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
> > >>>>>>>>>> + if (sigismember(&sigs, sig)) {
> > >>>>>>>>>> return &sigact[sig];
> > >>>>>>>>>> }
> > >>>>>>>>>> return NULL;
> > >>>>>>>>>> @@ -4525,7 +4522,7 @@
> > >>>>>>>>>> void os::Linux::save_preinstalled_handler(int sig,
> > struct
> > >>>>>>>>>> sigaction& oldAct) {
> > >>>>>>>>>> assert(sig > 0 && sig < NSIG, "vm signal out of
> > expected
> > >>>>>>>>>> range");
> > >>>>>>>>>> sigact[sig] = oldAct;
> > >>>>>>>>>> - sigs |= (uint64_t)1 << (sig-1);
> > >>>>>>>>>> + sigaddset(&sigs, sig);
> > >>>>>>>>>> }
> > >>>>>>>>>>
> > >>>>>>>>>> // for diagnostic
> > >>>>>>>>>> @@ -4616,6 +4613,7 @@
> > >>>>>>>>>> (*begin_signal_setting)();
> > >>>>>>>>>> }
> > >>>>>>>>>>
> > >>>>>>>>>> + ::sigemptyset(&sigs);
> > >>>>>>>>>> set_signal_handler(SIGSEGV, true);
> > >>>>>>>>>> set_signal_handler(SIGPIPE, true);
> > >>>>>>>>>> set_signal_handler(SIGBUS, true);
> > >>>>>>>>>>
> > >>
> >
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