Re: [LTP] [PATCH v6 1/2] cpuset02: Convert the test6 from cpuset_memory_testset.sh to C code

Petr Vorel
2025-03-25T13:36:35Z

> Hi!
> > diff --git a/lib/tst_cgroup.c b/lib/tst_cgroup.c
> > index 73b696c58..545c779e7 100644
> > --- a/lib/tst_cgroup.c
> > +++ b/lib/tst_cgroup.c
> > @@ -204,6 +204,7 @@ static const struct cgroup_file cpuset_ctrl_files[] = {
> > { "cpuset.cpus", "cpuset.cpus", CTRL_CPUSET },
> > { "cpuset.mems", "cpuset.mems", CTRL_CPUSET },
> > { "cpuset.memory_migrate", "cpuset.memory_migrate", CTRL_CPUSET },
> > + { "cpuset.sched_load_balance", "cpuset.sched_load_balance", CTRL_CPUSET },
> > { }
> > };

> > diff --git a/runtest/mm b/runtest/mm
> > index d8e62af81..5af29b0ea 100644
> > --- a/runtest/mm
> > +++ b/runtest/mm
> > @@ -75,6 +75,7 @@ ksm06_2 ksm06 -n 8000
> > ksm07 ksm07

> > cpuset01 cpuset01
> > +cpuset02 cpuset02

> > oom01 oom01
> > oom02 oom02
> > diff --git a/testcases/kernel/mem/.gitignore b/testcases/kernel/mem/.gitignore
> > index 699e022fb..e24e96001 100644
> > --- a/testcases/kernel/mem/.gitignore
> > +++ b/testcases/kernel/mem/.gitignore
> > @@ -1,4 +1,5 @@
> > /cpuset/cpuset01
> > +/cpuset/cpuset02
> > /hugetlb/hugefallocate/hugefallocate01
> > /hugetlb/hugefallocate/hugefallocate02
> > /hugetlb/hugefork/hugefork01
> > diff --git a/testcases/kernel/mem/cpuset/Makefile b/testcases/kernel/mem/cpuset/Makefile
> > index bac13e02b..7010c7be4 100644
> > --- a/testcases/kernel/mem/cpuset/Makefile
> > +++ b/testcases/kernel/mem/cpuset/Makefile
> > @@ -19,6 +19,11 @@

> > top_srcdir ?= ../../../..

> > +LTPLIBS = numa
> > +
> > include $(top_srcdir)/include/mk/testcases.mk
> > include $(top_srcdir)/testcases/kernel/include/lib.mk
> > +
> > +cpuset02: LTPLDLIBS = -lltpnuma
> > +
> > include $(top_srcdir)/include/mk/generic_leaf_target.mk
> > diff --git a/testcases/kernel/mem/cpuset/cpuset02.c b/testcases/kernel/mem/cpuset/cpuset02.c
> > new file mode 100644
> > index 000000000..f43d8e98a
> > --- /dev/null
> > +++ b/testcases/kernel/mem/cpuset/cpuset02.c
> > @@ -0,0 +1,139 @@
> > +// SPDX-License-Identifier: LGPL-2.1-or-later
> > +/*
> > + * Copyright (c) 2009 FUJITSU LIMITED Miao Xie <miaox@cn.fujitsu.com>
> > + * Copyright (c) 2023 SUSE LLC <wegao@suse.com>
> > + */
> > +
> > +/*\
> > + * Test checks cpuset.mems works with hugepage file.
> > + */
> > +
> > +#define _GNU_SOURCE
> > +#include <stdio.h>
> > +#include <sys/mount.h>
> > +#include <limits.h>
> > +#include <sys/param.h>
> > +#include <sys/types.h>
> > +#include "tst_test.h"
> > +
> > +#ifdef HAVE_NUMA_V2
> > +#include <numa.h>
> > +#include <numaif.h>
> > +#include <errno.h>
> > +#include "tst_numa.h"
> > +#include "tst_safe_stdio.h"
> > +#include "numa_helper.h"
> > +
> > +#define MNTPOINT "hugetlbfs/"
> > +#define HUGE_PAGE_FILE MNTPOINT "hugepagefile"
> > +#define PAGES_ALLOCATED 16u
> > +
> > +static long hpage_size;
> > +static struct tst_nodemap *node;
> > +static struct tst_cg_group *cg_cpuset_0;
> > +
> > +static void touch_memory_and_check_node(char *p, int size)
> > +{
> > + int i;
> > + int node = -1;
> > + long ret;
> > + int pagesize = sysconf(_SC_PAGESIZE);
> > +
> > + for (i = 0; i < size; i += pagesize)
> > + p[i] = 0xef;
> > +
> > + ret = get_mempolicy(&node, NULL, 0, p, MPOL_F_NODE | MPOL_F_ADDR);
> > + if (ret < 0)
> > + tst_brk(TBROK | TERRNO, "get_mempolicy() failed");
> > +
> > + if (node == 0)
> > + tst_res(TPASS, "check node pass");
> > + else
> > + tst_res(TFAIL, "check node failed");
> > +}
> > +
> > +static void child(void)
> > +{
> > + char *p;
> > + int fd_hugepage;
> > +
> > + TST_CHECKPOINT_WAIT(0);
> > +
> > + fd_hugepage = SAFE_OPEN(HUGE_PAGE_FILE, O_CREAT | O_RDWR, 0755);
> > + p = SAFE_MMAP(NULL, hpage_size, PROT_WRITE | PROT_READ,
> > + MAP_SHARED, fd_hugepage, 0);
> > +
> > + touch_memory_and_check_node(p, hpage_size);
> > +
> > + SAFE_MUNMAP(p, hpage_size);
> > + SAFE_CLOSE(fd_hugepage);
> > +
> > + TST_CHECKPOINT_WAKE(1);
> > +}
> > +
> > +static void run_test(void)
> > +{
> > + int pid;
> > +
> > + cg_cpuset_0 = tst_cg_group_mk(tst_cg, "0");
> > +
> > + SAFE_CG_PRINT(cg_cpuset_0, "cpuset.cpus", "0");
> > + SAFE_CG_PRINT(cg_cpuset_0, "cpuset.mems", "0");
> > + SAFE_CG_PRINT(cg_cpuset_0, "cpuset.sched_load_balance", "0");

> Here you are locking the process to node0 but that does not necessarily
> means that the node0 has enough memory or CPUs. You have to choose a
> node from the nodemap that you got in the setup.

> Also if you want to have a node with CPU, so that you can lock the
> process there, you need to add TST_NUMA_CPU flag to the
> tst_get_nodemap(). And yes, there are machines that can have node with
> just memory or just CPU.

> However in the touch_memory_and_check_node() we just check a node the
> memory was allocated on. So I do not think that we need to lock the
> process on a particular CPU. And I do not think that we need the se the
> sched_load_balance either.

[ commenting old version, there is v7 already ]

Thanks for catching these. For a record original shell test does not set
cpuset.cpus, only cpuset.mems.

> > + SAFE_FILE_PRINTF("/proc/sys/vm/nr_hugepages", "%d", 2 * node->cnt);

> What is this needed for and why is there the 2*node->cnt useful for? As
> far as I can tell, we allocate a single page on a given node.

For a record, shell test does:

echo $((2*$nr_mems)) > /proc/sys/vm/nr_hugepages

I don't have deep understanding of hugetlbpage and NUMA, but kernel hugetlbpage
allows more huge pages in the kernel's huge page pool:
https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt

echo 20 > /proc/sys/vm/nr_hugepages

Kind regards,
Petr

> > + pid = SAFE_FORK();
> > +
> > + if (!pid) {
> > + child();
> > + return;
> > + }
> > +
> > + SAFE_CG_PRINTF(cg_cpuset_0, "cgroup.procs", "%d", pid);

> We can just get rid of all the checkpoints if this is done by the child
> process before it calls the child() function.

> > + TST_CHECKPOINT_WAKE(0);
> > + TST_CHECKPOINT_WAIT(1);
> > +
> > + SAFE_WAITPID(pid, NULL, 0);

> We should not wait processes if we are not interested in their return
> value. Such children are collected automatically by the test library.

> > + cg_cpuset_0 = tst_cg_group_rm(cg_cpuset_0);
> > +}
> > +
> > +static void setup(void)
> > +{
> > + node = tst_get_nodemap(TST_NUMA_MEM, PAGES_ALLOCATED * getpagesize() / 1024);
> ^
> Why is this here? The
> child in the test
> allocates just a single
> page.
> > + if (node->cnt <= 1)
> > + tst_brk(TCONF, "test requires NUMA system");
> > +
> > + hpage_size = SAFE_READ_MEMINFO(MEMINFO_HPAGE_SIZE)*1024;
> > +}
> > +
> > +static void cleanup(void)
> > +{
> > + if (cg_cpuset_0)
> > + cg_cpuset_0 = tst_cg_group_rm(cg_cpuset_0);
> > +}
> > +
> > +static struct tst_test test = {
> > + .needs_root = 1,
> > + .runs_script = 1,
> > + .mntpoint = MNTPOINT,
> > + .needs_hugetlbfs = 1,
> > + .setup = setup,
> > + .forks_child = 1,
> > + .cleanup = cleanup,
> > + .test_all = run_test,
> > + .hugepages = {3, TST_NEEDS},
> > + .needs_checkpoints = 1,
> > + .needs_cgroup_ver = TST_CG_V1,
> > + .needs_cgroup_ctrls = (const char *const []){ "cpuset", NULL },
> > + .save_restore = (const struct tst_path_val[]) {
> > + {"/proc/sys/vm/nr_hugepages", NULL, TST_SR_TBROK},
> > + {}
> > + },
> > +};
> > +
> > +#else
> > +TST_TEST_TCONF(NUMA_ERROR_MSG);
> > +#endif
> > --
> > 2.35.3

> > --
> > Mailing list info: https://lists.linux.it/listinfo/ltp