[LTP] [PATCH V2 2/3] mm/ksm: extend 'max_page_sharing' before ksm testing
Li Wang
liwang@redhat.com
Wed Mar 23 05:25:56 CET 2016
This kernel commit (de39e60a6, ksm: introduce ksm_max_page_sharing per page...)
introduced a new KSM sysfs knob '/sys/kernel/mm/ksm/max_page_sharing' in linux-next.
The runtime value of 'max_page_sharing' will affect pages_shared/pages_sharing,
because this enforces a deduplication limit to avoid the virtual memory rmap lists
to grow too large.
ltp/ksm0* tests can easily get failures on that kernel like:
-----
ksm01 0 TINFO : wait for all children to stop.
ksm01 0 TINFO : KSM merging...
ksm01 0 TINFO : resume all children.
ksm01 0 TINFO : child 2 stops.
...
ksm01 0 TINFO : run is 1.
ksm01 0 TINFO : pages_shared is 384.
ksm01 1 TFAIL : mem.c:238: pages_shared is not 2.
ksm01 0 TINFO : pages_sharing is 97920.
ksm01 2 TFAIL : mem.c:238: pages_sharing is not 98302.
ksm01 0 TINFO : pages_volatile is 0.
ksm01 0 TINFO : pages_unshared is 0.
ksm01 0 TINFO : sleep_millisecs is 0.
ksm01 0 TINFO : pages_to_scan is 98304.
This patch is intened to extend the 'max_page_sharing' value dynamically to
make tests pass.
Signed-off-by: Li Wang <liwang@redhat.com>
---
testcases/kernel/mem/include/mem.h | 3 +++
testcases/kernel/mem/ksm/ksm01.c | 4 ++++
testcases/kernel/mem/ksm/ksm02.c | 3 +++
testcases/kernel/mem/ksm/ksm03.c | 4 ++++
testcases/kernel/mem/ksm/ksm04.c | 4 ++++
testcases/kernel/mem/ksm/ksm06.c | 4 ++++
testcases/kernel/mem/lib/mem.c | 22 +++++++++++++++++++++-
7 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/testcases/kernel/mem/include/mem.h b/testcases/kernel/mem/include/mem.h
index 43988fe..69d08dd 100644
--- a/testcases/kernel/mem/include/mem.h
+++ b/testcases/kernel/mem/include/mem.h
@@ -43,7 +43,10 @@ void testoom(int mempolicy, int lite, int retcode, int allow_sigkill);
/* KSM */
#define PATH_KSM "/sys/kernel/mm/ksm/"
+int max_page_sharing;
+void save_max_page_sharing(void);
+void restore_max_page_sharing(void);
void test_ksm_merge_across_nodes(unsigned long nr_pages);
/* THP */
diff --git a/testcases/kernel/mem/ksm/ksm01.c b/testcases/kernel/mem/ksm/ksm01.c
index b62df06..824881c 100644
--- a/testcases/kernel/mem/ksm/ksm01.c
+++ b/testcases/kernel/mem/ksm/ksm01.c
@@ -106,6 +106,8 @@ void setup(void)
if (access(PATH_KSM, F_OK) == -1)
tst_brkm(TCONF, NULL, "KSM configuration is not enabled");
+ save_max_page_sharing();
+
/*
* kernel commit 90bd6fd introduced a new KSM sysfs knob
* /sys/kernel/mm/ksm/merge_across_nodes, setting it to '0'
@@ -128,4 +130,6 @@ void cleanup(void)
if (access(PATH_KSM "merge_across_nodes", F_OK) == 0)
FILE_PRINTF(PATH_KSM "merge_across_nodes",
"%d", merge_across_nodes);
+
+ restore_max_page_sharing();
}
diff --git a/testcases/kernel/mem/ksm/ksm02.c b/testcases/kernel/mem/ksm/ksm02.c
index 537ec01..6274f8a 100644
--- a/testcases/kernel/mem/ksm/ksm02.c
+++ b/testcases/kernel/mem/ksm/ksm02.c
@@ -125,6 +125,8 @@ void cleanup(void)
FILE_PRINTF(PATH_KSM "merge_across_nodes",
"%d", merge_across_nodes);
+ restore_max_page_sharing();
+
umount_mem(CPATH, CPATH_NEW);
}
@@ -136,6 +138,7 @@ void setup(void)
tst_brkm(TCONF, NULL, "2.6.32 or greater kernel required");
if (access(PATH_KSM, F_OK) == -1)
tst_brkm(TCONF, NULL, "KSM configuration is not enabled");
+ save_max_page_sharing();
if (access(PATH_KSM "merge_across_nodes", F_OK) == 0) {
SAFE_FILE_SCANF(NULL, PATH_KSM "merge_across_nodes",
diff --git a/testcases/kernel/mem/ksm/ksm03.c b/testcases/kernel/mem/ksm/ksm03.c
index b73e023..979222a 100644
--- a/testcases/kernel/mem/ksm/ksm03.c
+++ b/testcases/kernel/mem/ksm/ksm03.c
@@ -113,6 +113,8 @@ void setup(void)
SAFE_FILE_PRINTF(NULL, PATH_KSM "merge_across_nodes", "1");
}
+ save_max_page_sharing();
+
mount_mem("memcg", "cgroup", "memory", MEMCG_PATH, MEMCG_PATH_NEW);
tst_sig(FORK, DEF_HANDLER, NULL);
TEST_PAUSE;
@@ -124,5 +126,7 @@ void cleanup(void)
FILE_PRINTF(PATH_KSM "merge_across_nodes",
"%d", merge_across_nodes);
+ restore_max_page_sharing();
+
umount_mem(MEMCG_PATH, MEMCG_PATH_NEW);
}
diff --git a/testcases/kernel/mem/ksm/ksm04.c b/testcases/kernel/mem/ksm/ksm04.c
index 0c1d4e0..4beeed6 100644
--- a/testcases/kernel/mem/ksm/ksm04.c
+++ b/testcases/kernel/mem/ksm/ksm04.c
@@ -127,6 +127,8 @@ void cleanup(void)
FILE_PRINTF(PATH_KSM "merge_across_nodes",
"%d", merge_across_nodes);
+ restore_max_page_sharing();
+
umount_mem(CPATH, CPATH_NEW);
umount_mem(MEMCG_PATH, MEMCG_PATH_NEW);
}
@@ -146,6 +148,8 @@ void setup(void)
SAFE_FILE_PRINTF(NULL, PATH_KSM "merge_across_nodes", "1");
}
+ save_max_page_sharing();
+
tst_sig(FORK, DEF_HANDLER, cleanup);
TEST_PAUSE;
mount_mem("cpuset", "cpuset", NULL, CPATH, CPATH_NEW);
diff --git a/testcases/kernel/mem/ksm/ksm06.c b/testcases/kernel/mem/ksm/ksm06.c
index 02d304f..2092746 100644
--- a/testcases/kernel/mem/ksm/ksm06.c
+++ b/testcases/kernel/mem/ksm/ksm06.c
@@ -105,6 +105,8 @@ void setup(void)
SAFE_FILE_SCANF(NULL, PATH_KSM "sleep_millisecs",
"%d", &sleep_millisecs);
+ save_max_page_sharing();
+
tst_sig(FORK, DEF_HANDLER, cleanup);
TEST_PAUSE;
}
@@ -116,6 +118,8 @@ void cleanup(void)
FILE_PRINTF(PATH_KSM "sleep_millisecs",
"%d", sleep_millisecs);
FILE_PRINTF(PATH_KSM "run", "%d", run);
+
+ restore_max_page_sharing();
}
static void usage(void)
diff --git a/testcases/kernel/mem/lib/mem.c b/testcases/kernel/mem/lib/mem.c
index 7b5bb35..084e5a4 100644
--- a/testcases/kernel/mem/lib/mem.c
+++ b/testcases/kernel/mem/lib/mem.c
@@ -230,6 +230,20 @@ void testoom(int mempolicy, int lite, int retcode, int allow_sigkill)
/* KSM */
+void save_max_page_sharing(void)
+{
+ if (access(PATH_KSM "max_page_sharing", F_OK) == 0)
+ SAFE_FILE_SCANF(NULL, PATH_KSM "max_page_sharing",
+ "%d", &max_page_sharing);
+}
+
+void restore_max_page_sharing(void)
+{
+ if (access(PATH_KSM "max_page_sharing", F_OK) == 0)
+ FILE_PRINTF(PATH_KSM "max_page_sharing",
+ "%d", max_page_sharing);
+}
+
static void check(char *path, long int value)
{
char fullpath[BUFSIZ];
@@ -502,9 +516,12 @@ void create_same_memory(int size, int num, int unit)
stop_ksm_children(child, num);
tst_resm(TINFO, "KSM merging...");
+ if (access(PATH_KSM "max_page_sharing", F_OK) == 0)
+ SAFE_FILE_PRINTF(cleanup, PATH_KSM "max_page_sharing",
+ "%ld", size * pages * num);
SAFE_FILE_PRINTF(cleanup, PATH_KSM "run", "1");
SAFE_FILE_PRINTF(cleanup, PATH_KSM "pages_to_scan", "%ld",
- size * pages *num);
+ size * pages * num);
SAFE_FILE_PRINTF(cleanup, PATH_KSM "sleep_millisecs", "0");
resume_ksm_children(child, num);
@@ -595,6 +612,9 @@ void test_ksm_merge_across_nodes(unsigned long nr_pages)
SAFE_FILE_PRINTF(cleanup, PATH_KSM "sleep_millisecs", "0");
SAFE_FILE_PRINTF(cleanup, PATH_KSM "pages_to_scan", "%ld",
nr_pages * num_nodes);
+ if (access(PATH_KSM "max_page_sharing", F_OK) == 0)
+ SAFE_FILE_PRINTF(cleanup, PATH_KSM "max_page_sharing",
+ "%ld", nr_pages * num_nodes);
/*
* merge_across_nodes setting can be changed only when there
* are no ksm shared pages in system, so set run 2 to unmerge
--
1.8.3.1
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