[LTP] [PATCH 1/3] libltpswap: Add get_maxswapfiles api

Yang Xu
2023-12-05T06:17:25Z

Current, the kernel constant MAX_SWAPFILES value is calculated as below
------------------------------------
//#ifdef CONFIG_DEVICE_PRIVATE
//#define SWP_DEVICE_NUM 4
//#else
//#define SWP_DEVICE_NUM 0
//#endif

//#ifdef CONFIG_MIGRATION
//#define SWP_MIGRATION_NUM 3
//#else
//#define SWP_MIGRATION_NUM 0

//#ifdef CONFIG_MEMORY_FAILURE
//#define SWP_HWPOISON_NUM 1
//#else
//#define SWP_HWPOISON_NUM 0
//#endif

//#define SWP_PTE_MARKER_NUM 1
//#define MAX_SWAPFILES_SHIFT 5

//#define MAX_SWAPFILES \
// ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
// SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \
// SWP_PTE_MARKER_NUM)
------------------------------------

Also, man-pages missed something after 5.14 kernel. I have sent two patches to
add it.

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
---
include/libswap.h | 6 ++++++
libs/libltpswap/libswap.c | 41 +++++++++++++++++++++++++++++++++++++++
2 files changed, 47 insertions(+)

diff --git a/include/libswap.h b/include/libswap.h
index d4b5301a5..2cab1047d 100644
--- a/include/libswap.h
+++ b/include/libswap.h
@@ -21,4 +21,10 @@ int make_swapfile(const char *swapfile, int safe);
* we are testing on.
*/
void is_swap_supported(const char *filename);
+
+/*
+ * Get kernel constant MAX_SWAPFILES value
+ */
+unsigned int get_maxswapfiles(void);
+
#endif /* __LIBSWAP_H__ */
diff --git a/libs/libltpswap/libswap.c b/libs/libltpswap/libswap.c
index a4427736f..54317c627 100644
--- a/libs/libltpswap/libswap.c
+++ b/libs/libltpswap/libswap.c
@@ -11,6 +11,7 @@
#include "tst_test.h"
#include "libswap.h"
#include "lapi/syscalls.h"
+#include "tst_kconfig.h"

/*
* Make a swap file
@@ -63,3 +64,43 @@ void is_swap_supported(const char *filename)
if (TST_RET == -1)
tst_brk(TFAIL | TTERRNO, "swapoff on %s failed", fstype);
}
+
+/*
+ * Get kernel constant MAX_SWAPFILES value
+ */
+unsigned int get_maxswapfiles(void)
+{
+ unsigned int max_swapfile = 32;
+ unsigned int swp_migration_num = 0, swp_hwpoison_num = 0, swp_device_num = 0, swp_pte_marker_num = 0;
+ struct tst_kconfig_var migration_kconfig = TST_KCONFIG_INIT("CONFIG_MIGRATION");
+ struct tst_kconfig_var memory_kconfig = TST_KCONFIG_INIT("CONFIG_MEMORY_FAILURE");
+ struct tst_kconfig_var device_kconfig = TST_KCONFIG_INIT("CONFIG_DEVICE_PRIVATE");
+ struct tst_kconfig_var marker_kconfig = TST_KCONFIG_INIT("CONFIG_PTE_MARKER");
+
+ tst_kconfig_read(&migration_kconfig, 1);
+ tst_kconfig_read(&memory_kconfig, 1);
+ tst_kconfig_read(&device_kconfig, 1);
+ tst_kconfig_read(&marker_kconfig, 1);
+
+ if (migration_kconfig.choice == 'y') {
+ if (tst_kvercmp(5, 19, 0) < 0)
+ swp_migration_num = 2;
+ else
+ swp_migration_num = 3;
+ }
+
+ if (memory_kconfig.choice == 'y')
+ swp_hwpoison_num = 1;
+
+ if (device_kconfig.choice == 'y') {
+ if (tst_kvercmp(5, 14, 0) >= 0)
+ swp_device_num = 4;
+ }
+
+ if (marker_kconfig.choice == 'y') {
+ if (tst_kvercmp(5, 19, 0) < 0)
+ swp_pte_marker_num = 1;
+ }
+
+ return max_swapfile - swp_migration_num - swp_hwpoison_num - swp_device_num - swp_pte_marker_num;
+}
--
2.27.0