Re: [kselftests] compaction_test is blocked
From: Li Zhijian
Date: Mon Feb 12 2018 - 04:58:58 EST
On 2018å02æ12æ 11:26, Li Zhijian wrote:
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:
-------------------
 [ 111.750543] main: 248
 [ 111.750544]-
 [ 111.750821] check_compaction: 98
 [ 111.750822]-
 [ 111.751102] check_compaction: 105
 [ 111.751103]-
 [ 111.751362] check_compaction: 111
 [ 111.751363]-
 [ 111.751621] check_compaction: 118
 [ 111.751622]-
 [ 111.751879] check_compaction: 123
 [ 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.
Hi Dan,
I ran this case on this commit 4c1baad22390, this issue still occurs.
root@ivb44 ~# dmesg | tail -n 30
[Â 105.825870] main: 247
[Â 105.825994] main: 242
[Â 105.826130] main: 247
[Â 105.826250] main: 242
[Â 105.826394] main: 247
[Â 105.826506] main: 242
[Â 105.826617] main: 247
[Â 105.826728] main: 242
[Â 105.826840] main: 247
[Â 105.826950] main: 250
[Â 105.827272] check_compaction: 98
[Â 105.827589] check_compaction: 105
[Â 105.827849] check_compaction: 111
[Â 105.828152] check_compaction: 118
[Â 105.828451] check_compaction: 123
the runtime code is like
-------------------
110
111ÂÂÂÂÂÂÂÂ fprintf(stderr, "%s: %d\n", __func__, __LINE__);
112ÂÂÂÂÂÂÂÂ /* Start with the initial condition of 0 huge pages*/
113ÂÂÂÂÂÂÂÂ if (write(fd, "0", sizeof(char)) != sizeof(char)) {
114ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ perror("Failed to write 0 to
/proc/sys/vm/nr_hugepages\n");
115ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ goto close_fd;
116 }
117
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__);
124ÂÂÂÂÂÂÂÂ if (write(fd, "100000", (6*sizeof(char))) !=
(6*sizeof(char))) {
125ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ perror("Failed to write 100000 to
/proc/sys/vm/nr_hugepages\n");
126ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ goto close_fd;
127ÂÂÂÂÂÂÂÂ }
-------------------
Thanks
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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