move_pages() is best effort and can temporarily fail when concurrent faults race with page unmapping. A busy shared-anon workload can exhaust the current 100 retries long before the intended 20-second runtime and produce a false failure.
Use the full runtime as the retry window. Since the initial page location is unknown, require it to reach both alternating NUMA targets to confirm that cross-node migration made progress despite transient contention. Signed-off-by: Muhammad Usama Anjum <[email protected]> --- Changes since v1: - Retry per-page failures for the full runtime - Verify that both alternating NUMA targets are reached --- tools/testing/selftests/mm/migration.c | 39 ++++++++++++++------------ 1 file changed, 21 insertions(+), 18 deletions(-) diff --git a/tools/testing/selftests/mm/migration.c b/tools/testing/selftests/mm/migration.c index 29f7492453d43..4d55a424058a9 100644 --- a/tools/testing/selftests/mm/migration.c +++ b/tools/testing/selftests/mm/migration.c @@ -7,7 +7,7 @@ #include "kselftest_harness.h" #include "hugepage_settings.h" -#include <strings.h> +#include <string.h> #include <pthread.h> #include <numa.h> #include <numaif.h> @@ -20,7 +20,6 @@ #define TWOMEG (2<<20) #define RUNTIME (20) -#define MAX_RETRIES 100 #define ALIGN(x, a) (((x) + (a - 1)) & (~((a) - 1))) HUGETLB_SETUP_DEFAULT_PAGES(1) @@ -110,7 +109,7 @@ int migrate(uint64_t *ptr, int n1, int n2) int ret, tmp; int status = 0; struct timespec ts1, ts2; - int failures = 0; + int success = 0; if (clock_gettime(CLOCK_MONOTONIC, &ts1)) return -1; @@ -119,29 +118,33 @@ int migrate(uint64_t *ptr, int n1, int n2) if (clock_gettime(CLOCK_MONOTONIC, &ts2)) return -1; - if (ts2.tv_sec - ts1.tv_sec >= RUNTIME) - return 0; + if (ts2.tv_sec - ts1.tv_sec >= RUNTIME) { + /* Reaching both targets verifies a cross-node move. */ + if (success >= 2) + return 0; + else + return -2; + } ret = move_pages(0, 1, (void **) &ptr, &n2, &status, MPOL_MF_MOVE_ALL); - if (ret) { - if (ret > 0) { - /* Migration is best effort; try again */ - if (++failures < MAX_RETRIES) - continue; - printf("Didn't migrate %d pages\n", ret); - } - else - perror("Couldn't migrate pages"); - return -2; + if (ret < 0) { + perror("Couldn't migrate pages"); + return ret; } - failures = 0; + /* Migration is best effort. Try again */ + if (ret > 0 || status < 0) + continue; + if (status != n2) { + printf("Page is on node %d instead of target node %d\n", + status, n2); + return status; + } + success++; tmp = n2; n2 = n1; n1 = tmp; } - - return 0; } void *access_mem(void *ptr) -- 2.47.3
