Re: [kselftests] compaction_test is blocked

[Li Zhijian]

On 2018å02æ11æ 13:44, Li Zhijian wrote:
> On 02/10/2018 05:11 AM, Dan Rue wrote:
> > On Fri, Feb 09, 2018 at 03:53:59PM +0800, Li Zhijian wrote:
> > > Hi
> > >
> > > kselftests is integrated Intel 0Day project.
> > > Sometimes we found compaction_test is blocked for more than 1 hours 
> > > until i kill it.
> > >
> > > Try to figure out where it is running, i added some log to this case.
> > >
> > > the test log is like:
> > > -------------------
> > > Â [Â 111.750543] main: 248
> > > Â [Â 111.750544]-
> > > Â [ 111.750821] check_compaction: 98
> > > Â [Â 111.750822]-
> > > Â [Â 111.751102] check_compaction: 105
> > > Â [Â 111.751103]-
> > > Â [Â 111.751362] check_compaction: 111
> > > Â [Â 111.751363]-
> > > Â [Â 111.751621] check_compaction: 118
> > > Â [Â 111.751622]-
> > > Â [Â 111.751879] check_compaction: 123
> > > Â [Â 111.751880]-
> > > -------------------
> > > 118ÂÂÂÂÂÂÂÂ fprintf(stderr, "%s: %d\n", __func__, __LINE__);
> > > 119ÂÂÂÂÂÂÂÂ lseek(fd, 0, SEEK_SET);
> > > 120
> > > 121ÂÂÂÂÂÂÂÂ /* Request a large number of huge pages. The Kernel will 
> > > allocate
> > > 122ÂÂÂÂÂÂÂÂÂÂÂ as much as it can */
> > > 123ÂÂÂÂÂÂÂÂ fprintf(stderr, "%s: %d\n", __func__, __LINE__);ÂÂÂÂÂÂÂÂ 
> > > <<<======== the last line we can catch.
> > > 124ÂÂÂÂÂÂÂÂ if (write(fd, "100000", (6*sizeof(char))) != 
> > > (6*sizeof(char))) {ÂÂÂÂÂÂÂ <<<<============ blocking position
> > > 125ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ perror("Failed to write 100000 to 
> > > /proc/sys/vm/nr_hugepages\n");
> > > 126ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ goto close_fd;
> > > 127ÂÂÂÂÂÂÂÂ }
> > > 128
> > > 129ÂÂÂÂÂÂÂÂ lseek(fd, 0, SEEK_SET);
> > > 130
> > > 131ÂÂÂÂÂÂÂÂ fprintf(stderr, "%s: %d\n", __func__, __LINE__);
> > > 132ÂÂÂÂÂÂÂÂ if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {
> > > 133ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ perror("Failed to re-read from 
> > > /proc/sys/vm/nr_hugepages\n");
> > > 134ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ goto close_fd;
> > > 135ÂÂÂÂÂÂÂÂ }
> > > -------------------
> > >
> > > According to above log and code, it most likely it is blocking at 
> > > the writing operation.
> > >
> > > my environment is like:
> > > OS: debian
> > > kernel: v4.15
> > > model: Ivytown Ivy Bridge-EP
> > > nr_cpu: 48
> > > memory: 64G
> > Hi Zhijian,
> >
> > Please try this patch in mainline:
> >
> > ÂÂÂÂ 4c1baad22390 kselftest: fix OOM in memory compaction test
>
> Hi Dan
>
> Thanks for your replies.
>
> I run this case on v4.15, looks this patch is already merged to v4.15.
> lizhijian@inn:~/linux$ git describe 4c1baad
> v4.15-rc2-2-g4c1baad223906

My mistake, this path is not contained by v4.15 yet.
i will have a try.

Thanks



> Thanks
>
> > Dan
> >
> > > NOTE: 0Day can reproduce this issue in 20% on 0Day.
> > >
> > > Anybody can help have a look?
> > >
> > > Thanks
> > > Zhjian
> > >
> > >
> > >
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