Re: [PATCH v3 03/54] selftests/mm: migration: make nthreads represent number of working threads

Thu, 30 Apr 2026 06:21:51 -0700 

On 2026-04-28 16:41, Mike Rapoport wrote:

From: "Mike Rapoport (Microsoft)" <[email protected]>

Fixture setup sets self->nthreads to number of available CPUs minus 1
and then each test creates 'self->nthreads - 1' threads or processes, so
essentially nthreads counts the worker tasks and the main task.

Make nthreads represent the number of spawned tasks to simplify
thread/process creation and teardown.

While on it, make the fixture setup skip the tests if there are not
enough CPUs or NUMA nodes instead of checking this in each test.

Signed-off-by: Mike Rapoport (Microsoft) <[email protected]>


Reviewed-by: Luiz Capitulino <[email protected]>


---
  tools/testing/selftests/mm/migration.c | 47 +++++++++-----------------
  1 file changed, 16 insertions(+), 31 deletions(-)

diff --git a/tools/testing/selftests/mm/migration.c 
b/tools/testing/selftests/mm/migration.c
index 7e547d945e1a..3630f2fb0800 100644
--- a/tools/testing/selftests/mm/migration.c
+++ b/tools/testing/selftests/mm/migration.c
@@ -38,7 +38,7 @@ FIXTURE_SETUP(migration)
if (numa_available() < 0) 
                SKIP(return, "NUMA not available");
-       self->nthreads = numa_num_task_cpus() - 1;
+       self->nthreads = numa_num_task_cpus() - 2;
        self->n1 = -1;
        self->n2 = -1;
@@ -52,6 +52,9 @@ FIXTURE_SETUP(migration) 
                        }
                }
+ if (self->nthreads < 1 || self->n1 < 0 || self->n2 < 0) 
+               SKIP(return, "Not enough threads or NUMA nodes available");
+
        self->threads = malloc(self->nthreads * sizeof(*self->threads));
        ASSERT_NE(self->threads, NULL);
        self->pids = malloc(self->nthreads * sizeof(*self->pids));
@@ -127,20 +130,17 @@ TEST_F_TIMEOUT(migration, private_anon, 2*RUNTIME)
        uint64_t *ptr;
        int i;
- if (self->nthreads < 2 || self->n1 < 0 || self->n2 < 0) 
-               SKIP(return, "Not enough threads or NUMA nodes available");
-
        ptr = mmap(NULL, TWOMEG, PROT_READ | PROT_WRITE,
                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
        ASSERT_NE(ptr, MAP_FAILED);
memset(ptr, 0xde, TWOMEG); 
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                if (pthread_create(&self->threads[i], NULL, access_mem, ptr))
                        perror("Couldn't create thread");
ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0); 
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                ASSERT_EQ(pthread_cancel(self->threads[i]), 0);
  }
@@ -153,15 +153,12 @@ TEST_F_TIMEOUT(migration, shared_anon, 2*RUNTIME) 
        uint64_t *ptr;
        int i;
- if (self->nthreads < 2 || self->n1 < 0 || self->n2 < 0) 
-               SKIP(return, "Not enough threads or NUMA nodes available");
-
        ptr = mmap(NULL, TWOMEG, PROT_READ | PROT_WRITE,
                MAP_SHARED | MAP_ANONYMOUS, -1, 0);
        ASSERT_NE(ptr, MAP_FAILED);
memset(ptr, 0xde, TWOMEG); 
-       for (i = 0; i < self->nthreads - 1; i++) {
+       for (i = 0; i < self->nthreads; i++) {
                pid = fork();
                if (!pid) {
                        prctl(PR_SET_PDEATHSIG, SIGHUP);
@@ -175,7 +172,7 @@ TEST_F_TIMEOUT(migration, shared_anon, 2*RUNTIME)
        }
ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0); 
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                ASSERT_EQ(kill(self->pids[i], SIGTERM), 0);
  }
@@ -195,9 +192,6 @@ TEST_F_TIMEOUT(migration, private_anon_thp, 2*RUNTIME) 
        if (!pmdsize)
                SKIP(return, "Reading PMD pagesize failed");
- if (self->nthreads < 2 || self->n1 < 0 || self->n2 < 0) 
-               SKIP(return, "Not enough threads or NUMA nodes available");
-
        ptr = mmap(NULL, 2 * pmdsize, PROT_READ | PROT_WRITE,
                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
        ASSERT_NE(ptr, MAP_FAILED);
@@ -205,12 +199,12 @@ TEST_F_TIMEOUT(migration, private_anon_thp, 2*RUNTIME)
        ptr = (uint64_t *) ALIGN((uintptr_t) ptr, pmdsize);
        ASSERT_EQ(madvise(ptr, pmdsize, MADV_HUGEPAGE), 0);
        memset(ptr, 0xde, pmdsize);
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                if (pthread_create(&self->threads[i], NULL, access_mem, ptr))
                        perror("Couldn't create thread");
ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0); 
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                ASSERT_EQ(pthread_cancel(self->threads[i]), 0);
  }
@@ -232,9 +226,6 @@ TEST_F_TIMEOUT(migration, shared_anon_thp, 2*RUNTIME) 
        if (!pmdsize)
                SKIP(return, "Reading PMD pagesize failed");
- if (self->nthreads < 2 || self->n1 < 0 || self->n2 < 0) 
-               SKIP(return, "Not enough threads or NUMA nodes available");
-
        ptr = mmap(NULL, 2 * pmdsize, PROT_READ | PROT_WRITE,
                MAP_SHARED | MAP_ANONYMOUS, -1, 0);
        ASSERT_NE(ptr, MAP_FAILED);
@@ -243,7 +234,7 @@ TEST_F_TIMEOUT(migration, shared_anon_thp, 2*RUNTIME)
        ASSERT_EQ(madvise(ptr, pmdsize, MADV_HUGEPAGE), 0);
memset(ptr, 0xde, pmdsize); 
-       for (i = 0; i < self->nthreads - 1; i++) {
+       for (i = 0; i < self->nthreads; i++) {
                pid = fork();
                if (!pid) {
                        prctl(PR_SET_PDEATHSIG, SIGHUP);
@@ -257,7 +248,7 @@ TEST_F_TIMEOUT(migration, shared_anon_thp, 2*RUNTIME)
        }
ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0); 
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                ASSERT_EQ(kill(self->pids[i], SIGTERM), 0);
  }
@@ -270,9 +261,6 @@ TEST_F_TIMEOUT(migration, private_anon_htlb, 2*RUNTIME) 
        uint64_t *ptr;
        int i;
- if (self->nthreads < 2 || self->n1 < 0 || self->n2 < 0) 
-               SKIP(return, "Not enough threads or NUMA nodes available");
-
        hugepage_size = default_huge_page_size();
        if (!hugepage_size)
                SKIP(return, "Reading HugeTLB pagesize failed\n");
@@ -282,12 +270,12 @@ TEST_F_TIMEOUT(migration, private_anon_htlb, 2*RUNTIME)
        ASSERT_NE(ptr, MAP_FAILED);
memset(ptr, 0xde, hugepage_size); 
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                if (pthread_create(&self->threads[i], NULL, access_mem, ptr))
                        perror("Couldn't create thread");
ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0); 
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                ASSERT_EQ(pthread_cancel(self->threads[i]), 0);
  }
@@ -301,9 +289,6 @@ TEST_F_TIMEOUT(migration, shared_anon_htlb, 2*RUNTIME) 
        uint64_t *ptr;
        int i;
- if (self->nthreads < 2 || self->n1 < 0 || self->n2 < 0) 
-               SKIP(return, "Not enough threads or NUMA nodes available");
-
        hugepage_size = default_huge_page_size();
        if (!hugepage_size)
                SKIP(return, "Reading HugeTLB pagesize failed\n");
@@ -313,7 +298,7 @@ TEST_F_TIMEOUT(migration, shared_anon_htlb, 2*RUNTIME)
        ASSERT_NE(ptr, MAP_FAILED);
memset(ptr, 0xde, hugepage_size); 
-       for (i = 0; i < self->nthreads - 1; i++) {
+       for (i = 0; i < self->nthreads; i++) {
                pid = fork();
                if (!pid) {
                        prctl(PR_SET_PDEATHSIG, SIGHUP);
@@ -327,7 +312,7 @@ TEST_F_TIMEOUT(migration, shared_anon_htlb, 2*RUNTIME)
        }
ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0); 
-       for (i = 0; i < self->nthreads - 1; i++)
+       for (i = 0; i < self->nthreads; i++)
                ASSERT_EQ(kill(self->pids[i], SIGTERM), 0);
  }

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