Re: [LTP] [PATCH] mem/hugeshmat: new case for hugepage leak inspection

[Li Wang <liwang@redhat.com>]

> ----- Original Message -----
> > From: "Li Wang" <liwang@redhat.com>
> > To: "Jan Stancek" <jstancek@redhat.com>
> > Cc: ltp-list@lists.sourceforge.net
> > Sent: Sunday, 4 January, 2015 4:10:38 AM
> > Subject: Re: [LTP] [PATCH] mem/hugeshmat: new case for hugepage leak
> > inspection
> > 
> > The regression has a long history, Patch in upstream 2.6.20-rc1
> > GIT: 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa.
> > https://lkml.org/lkml/2012/4/16/129
> 
> And fix is presumably this commit:
> 
> ommit c5c99429fa57dcf6e05203ebe3676db1ec646793
> Author: Larry Woodman <lwoodman@redhat.com>
> Date:   Thu Jan 24 05:49:25 2008 -0800
>     fix hugepages leak due to pagetable page sharing
> 
> It'd be nice to include this information somewhere in testcase or commit
> message.
> More comments below:
...
> > > > +int shared_hugepage(void)
> > > > +{
> > > > +	pid_t pid;
> > > > +	int status, shmid;
> > > > +	size_t size = (size_t)SIZE;
> > > > +	void *buf;
> > > > +
> > > > +	shmid = shmget(IPC_PRIVATE, size, SHM_HUGETLB | IPC_CREAT | 0777);
> > > > +	if (shmid < 0)
> > > > +		tst_brkm(TBROK | TERRNO, cleanup, "shmget");
> > > > +
> > > > +	buf = shmat(shmid, (void *)BOUNDARY, SHM_RND | 0777);
> 
> Does it make a difference where you attach shared segment? I'm slightly
> worried,
> that absolute address you picked may already be in use on some
> distros/arches.

Hi Jan,

Thank you for reviewing my stupid patch. :)

Actually I also don't know why using absolute address here, I doubt this 
manner are similar with the BZ occurred environment. The sleep(3) below as well.

Since the original case is too old to found out who is the author. I hope someone 
now could provide any useful discussion here, if not, I still feel we can use these 
code to cover the regression. What do you think?


A new patch:

Subject: [PATCH] mem/hugeshmat: new case for hugepage leak inspection

Description of Problem:
	When over 1GB shared memory was alocated in hugepage, the hugepage
	is not released though process finished.

The fix is this commit:
	commit c5c99429fa57dcf6e05203ebe3676db1ec646793
	Author: Larry Woodman <lwoodman@redhat.com>
	Date:   Thu Jan 24 05:49:25 2008 -0800
    	fix hugepages leak due to pagetable page sharing

Signed-off-by: Li Wang <liwang@redhat.com>
Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
 runtest/hugetlb                                    |   1 +
 testcases/kernel/mem/.gitignore                    |   1 +
 .../kernel/mem/hugetlb/hugeshmat/hugeshmat04.c     | 166 +++++++++++++++++++++
 3 files changed, 168 insertions(+)
 create mode 100644 testcases/kernel/mem/hugetlb/hugeshmat/hugeshmat04.c

diff --git a/runtest/hugetlb b/runtest/hugetlb
index 3eaf14c..805141d 100644
--- a/runtest/hugetlb
+++ b/runtest/hugetlb
@@ -10,6 +10,7 @@ hugemmap05_3 hugemmap05 -s -m
 hugeshmat01 hugeshmat01 -i 5
 hugeshmat02 hugeshmat02 -i 5
 hugeshmat03 hugeshmat03 -i 5
+hugeshmat04 hugeshamt04 -i 5
 
 hugeshmctl01 hugeshmctl01 -i 5
 hugeshmctl02 hugeshmctl02 -i 5
diff --git a/testcases/kernel/mem/.gitignore b/testcases/kernel/mem/.gitignore
index f96964c..c531563 100644
--- a/testcases/kernel/mem/.gitignore
+++ b/testcases/kernel/mem/.gitignore
@@ -6,6 +6,7 @@
 /hugetlb/hugeshmat/hugeshmat01
 /hugetlb/hugeshmat/hugeshmat02
 /hugetlb/hugeshmat/hugeshmat03
+/hugetlb/hugeshmat/hugeshmat04
 /hugetlb/hugeshmctl/hugeshmctl01
 /hugetlb/hugeshmctl/hugeshmctl02
 /hugetlb/hugeshmctl/hugeshmctl03
diff --git a/testcases/kernel/mem/hugetlb/hugeshmat/hugeshmat04.c b/testcases/kernel/mem/hugetlb/hugeshmat/hugeshmat04.c
new file mode 100644
index 0000000..43e9f3f
--- /dev/null
+++ b/testcases/kernel/mem/hugetlb/hugeshmat/hugeshmat04.c
@@ -0,0 +1,166 @@
+/*
+ *   Copyright (c) Linux Test Project, 2014
+ *
+ *   This program is free software;  you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program;  if not, write to the Free Software
+ *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ *   02110-1301 USA
+ */
+
+/*
+ * NAME
+ * 	hugeshmat04.c
+ *
+ * DESCRIPTION
+ *	hugeshmat04 - test for hugepage leak inspection.
+ *
+ *      Description of Problem:
+ *         When over 1GB shered memory was alocated in hugepage, the hugepage
+ *         is not released though process finished.
+ *
+ *         You need more than 2GB memory in test job
+ *
+ *	Test results:
+ *	   Successed: No regression found.
+ *	   Failed:    Regression detected.
+ *
+ * HISTORY
+ * 	05/2014 - Written by Fujistu Corp.
+ *	12/2014 - Port to LTP by Li Wang.
+ *
+ * RESTRICTIONS
+ * 	test must be run at root
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/shm.h>
+#include <sys/wait.h>
+
+#include "test.h"
+#include "mem.h"
+
+#define SIZE	(1024 * 1024 * 1024)
+#define BOUNDARY (1024 * 1024 * 1024)
+
+char *TCID = "hugeshmat04";
+int TST_TOTAL = 3;
+
+static long huge_total;
+static long huge_free;
+static long huge_free2;
+static long hugepages;
+static long orig_hugepages;
+
+static void shared_hugepage(void);
+
+int main(int ac, char **av)
+{
+	int lc, i;
+	const char *msg;
+
+	msg = parse_opts(ac, av, NULL, NULL);
+	if (msg != NULL)
+		tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);
+
+	setup();
+
+	for (lc = 0; TEST_LOOPING(lc); lc++) {
+		tst_count = 0;
+
+		for (i = 0; i < TST_TOTAL; i++) {
+
+			shared_hugepage();
+			huge_free2 = read_meminfo("HugePages_Free:");
+
+			if (huge_free2 != huge_free)
+				tst_brkm(TFAIL, cleanup,
+					"Test failed. Hugepage leak inspection.");
+			else
+				tst_resm(TPASS, "No regression found.");
+		}
+	}
+
+	cleanup();
+	tst_exit();
+}
+
+void shared_hugepage(void)
+{
+	pid_t pid;
+	int status, shmid;
+	size_t size = (size_t)SIZE;
+	void *buf;
+
+	shmid = shmget(IPC_PRIVATE, size, SHM_HUGETLB | IPC_CREAT | 0777);
+	if (shmid < 0)
+		tst_brkm(TBROK | TERRNO, cleanup, "shmget");
+
+	buf = shmat(shmid, (void *)BOUNDARY, SHM_RND | 0777);
+	if (buf == (void *)-1) {
+		shmctl(shmid, IPC_RMID, NULL);
+		tst_brkm(TBROK | TERRNO, cleanup, "shmat");
+	}
+
+	memset(buf, 2, size);
+	sleep(3);
+	pid = fork();
+
+	if (pid == 0)
+		exit(1);
+	else if (pid < 0)
+		tst_brkm(TBROK | TERRNO, cleanup, "fork");
+
+	wait(&status);
+	shmdt(buf);
+	shmctl(shmid, IPC_RMID, NULL);
+}
+
+void setup(void)
+{
+	long mem_total, hpage_size;
+
+	tst_require_root(NULL);
+
+	mem_total = read_meminfo("MemTotal:") * 1024;
+	if (mem_total < 2L*SIZE) {
+		tst_resm(TINFO, "Total memory should greater than 2G.");
+		tst_exit();
+	}
+
+	orig_hugepages = get_sys_tune("nr_hugepages");
+	hpage_size = read_meminfo("Hugepagesize:") * 1024;
+
+	hugepages = (orig_hugepages * hpage_size + SIZE) / hpage_size;
+	set_sys_tune("nr_hugepages", hugepages, 1);
+
+	huge_total = read_meminfo("HugePages_Total:");
+	huge_free = read_meminfo("HugePages_Free:");
+
+	if (huge_total != hugepages || huge_free != hugepages)
+		tst_brkm(TCONF, cleanup,
+			"Maybe huge pages not enough for test.");
+
+	TEST_PAUSE;
+}
+
+void cleanup(void)
+{
+	TEST_CLEANUP;
+	set_sys_tune("nr_hugepages", orig_hugepages, 0);
+}
-- 
1.8.3.1

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