[LTP] [PATCH] swapon01: swapon01: prevent OOM happening in swap process

Li Wang liwang@redhat.com
Fri Mar 15 09:36:43 CET 2024


On Fri, Mar 15, 2024 at 3:44 PM Wei Gao <wegao@suse.com> wrote:

> On Fri, Mar 15, 2024 at 02:24:48PM +0800, Li Wang wrote:
> > Here we take many ways to prevent the OOM happening with
> > run the swapon test:
> >
> >   * shrink the pollute memory size
> >   * increase swapfile size
> >   * setting swap max for Cgroup
> >   * setting test oom_score_adj to -1000
> >
> > Reproted-by: Wei Gao <wegao@suse.com>
> > Signed-off-by: Li Wang <liwang@redhat.com>
> > ---
> >
> > Notes:
> >     Hi Wei,
> >
> >        Could you please test this patch and post the output messages?
> tst_device.c:97: TINFO: Found free device 1 '/dev/loop1'
> tst_test.c:1741: TINFO: LTP version: 20240129-94-g8f14b06e0
> tst_test.c:1627: TINFO: Timeout per run is 0h 00m 30s
> tst_supported_fs_types.c:97: TINFO: Kernel supports ext2
> tst_supported_fs_types.c:62: TINFO: mkfs.ext2 does exist
> tst_supported_fs_types.c:97: TINFO: Kernel supports ext3
> tst_supported_fs_types.c:62: TINFO: mkfs.ext3 does exist
> tst_supported_fs_types.c:97: TINFO: Kernel supports ext4
> tst_supported_fs_types.c:62: TINFO: mkfs.ext4 does exist
> tst_supported_fs_types.c:97: TINFO: Kernel supports xfs
> tst_supported_fs_types.c:62: TINFO: mkfs.xfs does exist
> tst_supported_fs_types.c:97: TINFO: Kernel supports btrfs
> tst_supported_fs_types.c:62: TINFO: mkfs.btrfs does exist
> tst_supported_fs_types.c:105: TINFO: Skipping bcachefs because of FUSE
> blacklist
> tst_supported_fs_types.c:97: TINFO: Kernel supports vfat
> tst_supported_fs_types.c:62: TINFO: mkfs.vfat does exist
> tst_supported_fs_types.c:97: TINFO: Kernel supports exfat
> tst_supported_fs_types.c:58: TINFO: mkfs.exfat does not exist
> tst_supported_fs_types.c:128: TINFO: Filesystem ntfs is not supported
> tst_supported_fs_types.c:97: TINFO: Kernel supports tmpfs
> tst_supported_fs_types.c:49: TINFO: mkfs is not needed for tmpfs
> tst_test.c:1701: TINFO: === Testing on ext2 ===
> tst_test.c:1118: TINFO: Formatting /dev/loop1 with ext2 opts='' extra
> opts=''
> mke2fs 1.47.0 (5-Feb-2023)
> tst_test.c:1132: TINFO: Mounting /dev/loop1 to /tmp/LTP_swafHGLPe/mntpoint
> fstyp=ext2 flags=0
> tst_ioctl.c:26: TINFO: FIBMAP ioctl is supported
> swapon01.c:27: TPASS: tst_syscall(__NR_swapon, SWAP_FILE, 0) passed
> swapon01.c:30: TINFO: SwapCached: 0 Kb
> tst_test.c:1701: TINFO: === Testing on ext3 ===
> tst_test.c:1118: TINFO: Formatting /dev/loop1 with ext3 opts='' extra
> opts=''
> mke2fs 1.47.0 (5-Feb-2023)
> tst_test.c:1132: TINFO: Mounting /dev/loop1 to /tmp/LTP_swafHGLPe/mntpoint
> fstyp=ext3 flags=0
> tst_ioctl.c:26: TINFO: FIBMAP ioctl is supported
> swapon01.c:27: TPASS: tst_syscall(__NR_swapon, SWAP_FILE, 0) passed
> swapon01.c:30: TINFO: SwapCached: 0 Kb
> tst_test.c:1701: TINFO: === Testing on ext4 ===
> tst_test.c:1118: TINFO: Formatting /dev/loop1 with ext4 opts='' extra
> opts=''
> mke2fs 1.47.0 (5-Feb-2023)
> tst_test.c:1132: TINFO: Mounting /dev/loop1 to /tmp/LTP_swafHGLPe/mntpoint
> fstyp=ext4 flags=0
> tst_ioctl.c:26: TINFO: FIBMAP ioctl is supported
> swapon01.c:27: TPASS: tst_syscall(__NR_swapon, SWAP_FILE, 0) passed
> swapon01.c:30: TINFO: SwapCached: 0 Kb
> tst_test.c:1701: TINFO: === Testing on xfs ===
> tst_test.c:1118: TINFO: Formatting /dev/loop1 with xfs opts='' extra
> opts=''
> tst_test.c:1132: TINFO: Mounting /dev/loop1 to /tmp/LTP_swafHGLPe/mntpoint
> fstyp=xfs flags=0
> tst_ioctl.c:26: TINFO: FIBMAP ioctl is supported
> swapon01.c:27: TPASS: tst_syscall(__NR_swapon, SWAP_FILE, 0) passed
> swapon01.c:30: TINFO: SwapCached: 0 Kb
> tst_test.c:1701: TINFO: === Testing on btrfs ===
> tst_test.c:1118: TINFO: Formatting /dev/loop1 with btrfs opts='' extra
> opts=''
> tst_test.c:1132: TINFO: Mounting /dev/loop1 to /tmp/LTP_swafHGLPe/mntpoint
> fstyp=btrfs flags=0
> libswap.c:42: TINFO: FS_NOCOW_FL attribute set on mntpoint/swapfile01
> tst_ioctl.c:21: TINFO: FIBMAP ioctl is NOT supported: EINVAL (22)
> libswap.c:125: TINFO: File 'mntpoint/swapfile01' is not contiguous
> libswap.c:42: TINFO: FS_NOCOW_FL attribute set on mntpoint/swapfile01
> swapon01.c:27: TPASS: tst_syscall(__NR_swapon, SWAP_FILE, 0) passed
> swapon01.c:30: TINFO: SwapCached: 0 Kb
> tst_test.c:1701: TINFO: === Testing on vfat ===
> tst_test.c:1118: TINFO: Formatting /dev/loop1 with vfat opts='' extra
> opts=''
> tst_test.c:1132: TINFO: Mounting /dev/loop1 to /tmp/LTP_swafHGLPe/mntpoint
> fstyp=vfat flags=0
> tst_ioctl.c:26: TINFO: FIBMAP ioctl is supported
> swapon01.c:27: TPASS: tst_syscall(__NR_swapon, SWAP_FILE, 0) passed
>


> swapon01.c:30: TINFO: SwapCached: 0 Kb
>

That's my concern here, with shrinking the polluted memory size,
swapping is not triggered, this is not what we expected.

And could you `cat /proc/sys/vm/swappiness` before doing the test?

An improved V2 (with setting swappiness to 60 percent):

--- a/testcases/kernel/syscalls/swapon/swapon01.c
+++ b/testcases/kernel/syscalls/swapon/swapon01.c
@@ -26,7 +26,7 @@ static void verify_swapon(void)
 {
        TST_EXP_PASS(tst_syscall(__NR_swapon, SWAP_FILE, 0));

-       tst_pollute_memory(TESTMEM, 0x41);
+       tst_pollute_memory(TESTMEM * 9/10, 0x41);
        tst_res(TINFO, "SwapCached: %ld Kb",
SAFE_READ_MEMINFO("SwapCached:"));

        if (TST_PASS && tst_syscall(__NR_swapoff, SWAP_FILE) != 0) {
@@ -37,11 +37,25 @@ static void verify_swapon(void)

 static void setup(void)
 {
+       tst_enable_oom_protection(0);
        is_swap_supported(SWAP_FILE);
-       make_swapfile(SWAP_FILE, 10, 0);
+       make_swapfile(SWAP_FILE, 1024, 0);

        SAFE_CG_PRINTF(tst_cg, "cgroup.procs", "%d", getpid());
        SAFE_CG_PRINTF(tst_cg, "memory.max", "%lu", TESTMEM);
+
+       if (SAFE_CG_HAS(tst_cg, "memory.swap.max"))
+               SAFE_CG_PRINTF(tst_cg, "memory.swap.max", "%ld", TESTMEM *
2);
+
+       if (SAFE_CG_HAS(tst_cg, "memory.swappiness"))
+               SAFE_CG_PRINT(tst_cg, "memory.swappiness", "60");
+       else
+               FILE_PRINTF("/proc/sys/vm/swappiness", "%d", 60);
+}
+
+static void cleanup(void)
+{
+       tst_disable_oom_protection(0);
 }

 static struct tst_test test = {
@@ -50,6 +64,12 @@ static struct tst_test test = {
        .needs_root = 1,
        .all_filesystems = 1,
        .needs_cgroup_ctrls = (const char *const []){ "memory", NULL },
+       .save_restore = (const struct tst_path_val[]) {
+               {"/proc/sys/vm/swappiness", NULL,
+                       TST_SR_SKIP_MISSING | TST_SR_TCONF_RO},
+               {}
+       },
        .test_all = verify_swapon,
-       .setup = setup
+       .setup = setup,
+       .cleanup = cleanup
 };




> tst_test.c:1701: TINFO: === Testing on tmpfs ===
> tst_test.c:1118: TINFO: Skipping mkfs for TMPFS filesystem
> tst_test.c:1098: TINFO: Limiting tmpfs size to 32MB
> tst_test.c:1132: TINFO: Mounting ltp-tmpfs to /tmp/LTP_swafHGLPe/mntpoint
> fstyp=tmpfs flags=0
> tst_ioctl.c:21: TINFO: FIBMAP ioctl is NOT supported: EINVAL (22)
> libswap.c:214: TCONF: Swapfile on tmpfs not implemented
>
> Summary:
> passed   6
> failed   0
> broken   0
> skipped  1
> warnings 0
>
>
> >        Thanks!!
> >
> >  testcases/kernel/syscalls/swapon/swapon01.c | 17 ++++++++++++++---
> >  1 file changed, 14 insertions(+), 3 deletions(-)
> >
> > diff --git a/testcases/kernel/syscalls/swapon/swapon01.c
> b/testcases/kernel/syscalls/swapon/swapon01.c
> > index d406e4bd9..b4fc02d6e 100644
> > --- a/testcases/kernel/syscalls/swapon/swapon01.c
> > +++ b/testcases/kernel/syscalls/swapon/swapon01.c
> > @@ -26,7 +26,7 @@ static void verify_swapon(void)
> >  {
> >       TST_EXP_PASS(tst_syscall(__NR_swapon, SWAP_FILE, 0));
> >
> > -     tst_pollute_memory(TESTMEM, 0x41);
> > +     tst_pollute_memory(TESTMEM * 9/10, 0x41);
> >       tst_res(TINFO, "SwapCached: %ld Kb",
> SAFE_READ_MEMINFO("SwapCached:"));
> >
> >       if (TST_PASS && tst_syscall(__NR_swapoff, SWAP_FILE) != 0) {
> > @@ -37,11 +37,21 @@ static void verify_swapon(void)
> >
> >  static void setup(void)
> >  {
> > +     tst_enable_oom_protection(0);
> >       is_swap_supported(SWAP_FILE);
> > -     make_swapfile(SWAP_FILE, 10, 0);
> > +     make_swapfile(SWAP_FILE, 1024, 0);
> >
> >       SAFE_CG_PRINTF(tst_cg, "cgroup.procs", "%d", getpid());
> >       SAFE_CG_PRINTF(tst_cg, "memory.max", "%lu", TESTMEM);
> > +     if (TST_CG_VER_IS_V1(tst_cg, "memory"))
> > +             SAFE_CG_PRINTF(tst_cg, "memory.swap.max", "%lu", ~0UL);
> > +     else
> > +             SAFE_CG_PRINT(tst_cg, "memory.swap.max", "max");
> > +}
> > +
> > +static void cleanup(void)
> > +{
> > +     tst_disable_oom_protection(0);
> >  }
> >
> >  static struct tst_test test = {
> > @@ -51,5 +61,6 @@ static struct tst_test test = {
> >       .all_filesystems = 1,
> >       .needs_cgroup_ctrls = (const char *const []){ "memory", NULL },
> >       .test_all = verify_swapon,
> > -     .setup = setup
> > +     .setup = setup,
> > +     .cleanup = cleanup
> >  };
> > --
> > 2.40.1
> >
>
>

-- 
Regards,
Li Wang


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