From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug alb_break_llc() decides whether to break LLC preference during active load balance. It does so by testing that every runnable fair task on the source rq prefers its LLC: env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable But the two counters cover different sets. nr_pref_llc_running is updated in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued, so it follows queued tasks. h_nr_runnable is updated in set_delayed()/ clear_delayed() and drops delay-dequeued tasks. So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks, alb_break_llc() returns false, and active balance is free to pull a task off its preferred LLC. Active balance only moves runnable tasks, and this is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB skips the per-task test in can_migrate_task(). The runnable set is the one we want. Fix it on the counter side. A task should be counted in nr_pref_llc_running exactly while it is both queued on its preferred LLC (pref_llc_queued) and runnable (!sched_delayed). Define that membership once in task_pref_llc_runnable(), and adjust the counter only through pref_llc_running_inc()/pref_llc_running_dec() from the four sites that change either input: account_llc_enqueue(), account_llc_dequeue(), set_delayed() and clear_delayed(). Gating every update on the same predicate keeps the delay, wake and dequeue paths from double-counting or underflowing; see the comments at those sites for the ordering. nr_llc_running and sd->llc_counts are not touched and stay on queued semantics. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC") Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/ Reported-by: Zhan Xusheng Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- tools/testing/selftests/kselftest.h | 490 ++++++++++++++++++++++++++++++++++++ 1 file changed, 490 insertions(+) create mode 100644 tools/testing/selftests/kselftest.h (limited to 'tools/testing/selftests/kselftest.h') diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h new file mode 100644 index 000000000..ae18c491a --- /dev/null +++ b/tools/testing/selftests/kselftest.h @@ -0,0 +1,490 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * kselftest.h: low-level kselftest framework to include from + * selftest programs. When possible, please use + * kselftest_harness.h instead. + * + * Copyright (c) 2014 Shuah Khan + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * + * Using this API consists of first counting how many tests your code + * has to run, and then starting up the reporting: + * + * ksft_print_header(); + * ksft_set_plan(total_number_of_tests); + * + * For each test, report any progress, debugging, etc with: + * + * ksft_print_msg(fmt, ...); + * ksft_perror(msg); + * + * and finally report the pass/fail/skip/xfail/xpass state of the test + * with one of: + * + * ksft_test_result(condition, fmt, ...); + * ksft_test_result_report(result, fmt, ...); + * ksft_test_result_pass(fmt, ...); + * ksft_test_result_fail(fmt, ...); + * ksft_test_result_skip(fmt, ...); + * ksft_test_result_xfail(fmt, ...); + * ksft_test_result_xpass(fmt, ...); + * ksft_test_result_error(fmt, ...); + * ksft_test_result_code(exit_code, test_name, fmt, ...); + * + * When all tests are finished, clean up and exit the program with one of: + * + * ksft_finished(); + * ksft_exit(condition); + * ksft_exit_pass(); + * ksft_exit_fail(); + * + * If the program wants to report details on why the entire program has + * failed, it can instead exit with a message (this is usually done when + * the program is aborting before finishing all tests): + * + * ksft_exit_fail_msg(fmt, ...); + * ksft_exit_fail_perror(msg); + * + */ +#ifndef __KSELFTEST_H +#define __KSELFTEST_H + +#ifndef NOLIBC +#include +#include +#include +#include +#include +#include +#include +#include +#endif + +#ifndef ARRAY_SIZE +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) +#endif + +#if defined(__i386__) || defined(__x86_64__) /* arch */ +/* + * gcc cpuid.h provides __cpuid_count() since v4.4. + * Clang/LLVM cpuid.h provides __cpuid_count() since v3.4.0. + * + * Provide local define for tests needing __cpuid_count() because + * selftests need to work in older environments that do not yet + * have __cpuid_count(). + */ +#ifndef __cpuid_count +#define __cpuid_count(level, count, a, b, c, d) \ + __asm__ __volatile__ ("cpuid\n\t" \ + : "=a" (a), "=b" (b), "=c" (c), "=d" (d) \ + : "0" (level), "2" (count)) +#endif +#endif /* end arch */ + +/* define kselftest exit codes */ +#define KSFT_PASS 0 +#define KSFT_FAIL 1 +#define KSFT_XFAIL 2 +#define KSFT_XPASS 3 +#define KSFT_SKIP 4 + +#ifndef __noreturn +#define __noreturn __attribute__((__noreturn__)) +#endif +#define __printf(a, b) __attribute__((format(printf, a, b))) + +#ifndef __always_unused +#define __always_unused __attribute__((__unused__)) +#endif + +#ifndef __maybe_unused +#define __maybe_unused __attribute__((__unused__)) +#endif + +/* counters */ +struct ksft_count { + unsigned int ksft_pass; + unsigned int ksft_fail; + unsigned int ksft_xfail; + unsigned int ksft_xpass; + unsigned int ksft_xskip; + unsigned int ksft_error; +}; + +static struct ksft_count ksft_cnt; +static unsigned int ksft_plan; +static bool ksft_debug_enabled; + +static inline unsigned int ksft_test_num(void) +{ + return ksft_cnt.ksft_pass + ksft_cnt.ksft_fail + + ksft_cnt.ksft_xfail + ksft_cnt.ksft_xpass + + ksft_cnt.ksft_xskip + ksft_cnt.ksft_error; +} + +static inline void ksft_inc_pass_cnt(void) { ksft_cnt.ksft_pass++; } +static inline void ksft_inc_fail_cnt(void) { ksft_cnt.ksft_fail++; } +static inline void ksft_inc_xfail_cnt(void) { ksft_cnt.ksft_xfail++; } +static inline void ksft_inc_xpass_cnt(void) { ksft_cnt.ksft_xpass++; } +static inline void ksft_inc_xskip_cnt(void) { ksft_cnt.ksft_xskip++; } +static inline void ksft_inc_error_cnt(void) { ksft_cnt.ksft_error++; } + +static inline int ksft_get_pass_cnt(void) { return ksft_cnt.ksft_pass; } +static inline int ksft_get_fail_cnt(void) { return ksft_cnt.ksft_fail; } +static inline int ksft_get_xfail_cnt(void) { return ksft_cnt.ksft_xfail; } +static inline int ksft_get_xpass_cnt(void) { return ksft_cnt.ksft_xpass; } +static inline int ksft_get_xskip_cnt(void) { return ksft_cnt.ksft_xskip; } +static inline int ksft_get_error_cnt(void) { return ksft_cnt.ksft_error; } + +static inline void ksft_print_header(void) +{ + /* + * Force line buffering; If stdout is not connected to a terminal, it + * will otherwise default to fully buffered, which can cause output + * duplication if there is content in the buffer when fork()ing. If + * there is a crash, line buffering also means the most recent output + * line will be visible. + */ + setvbuf(stdout, NULL, _IOLBF, 0); + + if (!(getenv("KSFT_TAP_LEVEL"))) + printf("TAP version 13\n"); +} + +static inline void ksft_set_plan(unsigned int plan) +{ + ksft_plan = plan; + printf("1..%u\n", ksft_plan); +} + +static inline void ksft_print_cnts(void) +{ + if (ksft_cnt.ksft_xskip > 0) + printf( + "# %u skipped test(s) detected. Consider enabling relevant config options to improve coverage.\n", + ksft_cnt.ksft_xskip + ); + if (ksft_plan != ksft_test_num()) + printf("# Planned tests != run tests (%u != %u)\n", + ksft_plan, ksft_test_num()); + printf("# Totals: pass:%u fail:%u xfail:%u xpass:%u skip:%u error:%u\n", + ksft_cnt.ksft_pass, ksft_cnt.ksft_fail, + ksft_cnt.ksft_xfail, ksft_cnt.ksft_xpass, + ksft_cnt.ksft_xskip, ksft_cnt.ksft_error); +} + +static inline __printf(1, 2) void ksft_print_msg(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + va_start(args, msg); + printf("# "); + errno = saved_errno; + vprintf(msg, args); + va_end(args); +} + +static inline void ksft_print_dbg_msg(const char *msg, ...) +{ + va_list args; + + if (!ksft_debug_enabled) + return; + + va_start(args, msg); + ksft_print_msg(msg, args); + va_end(args); +} + +static inline void ksft_perror(const char *msg) +{ + ksft_print_msg("%s: %s (%d)\n", msg, strerror(errno), errno); +} + +static inline __printf(1, 2) void ksft_test_result_pass(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + ksft_cnt.ksft_pass++; + + va_start(args, msg); + printf("ok %u ", ksft_test_num()); + errno = saved_errno; + vprintf(msg, args); + va_end(args); +} + +static inline __printf(1, 2) void ksft_test_result_fail(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + ksft_cnt.ksft_fail++; + + va_start(args, msg); + printf("not ok %u ", ksft_test_num()); + errno = saved_errno; + vprintf(msg, args); + va_end(args); +} + +/** + * ksft_test_result() - Report test success based on truth of condition + * + * @condition: if true, report test success, otherwise failure. + */ +#define ksft_test_result(condition, fmt, ...) do { \ + if (!!(condition)) \ + ksft_test_result_pass(fmt, ##__VA_ARGS__);\ + else \ + ksft_test_result_fail(fmt, ##__VA_ARGS__);\ + } while (0) + +static inline __printf(1, 2) void ksft_test_result_xfail(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + ksft_cnt.ksft_xfail++; + + va_start(args, msg); + printf("ok %u # XFAIL ", ksft_test_num()); + errno = saved_errno; + vprintf(msg, args); + va_end(args); +} + +static inline __printf(1, 2) void ksft_test_result_xpass(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + ksft_cnt.ksft_xpass++; + + va_start(args, msg); + printf("ok %u # XPASS ", ksft_test_num()); + errno = saved_errno; + vprintf(msg, args); + va_end(args); +} + +static inline __printf(1, 2) void ksft_test_result_skip(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + ksft_cnt.ksft_xskip++; + + va_start(args, msg); + printf("ok %u # SKIP ", ksft_test_num()); + errno = saved_errno; + vprintf(msg, args); + va_end(args); +} + +/* TODO: how does "error" differ from "fail" or "skip"? */ +static inline __printf(1, 2) void ksft_test_result_error(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + ksft_cnt.ksft_error++; + + va_start(args, msg); + printf("not ok %u # error ", ksft_test_num()); + errno = saved_errno; + vprintf(msg, args); + va_end(args); +} + +static inline __printf(3, 4) +void ksft_test_result_code(int exit_code, const char *test_name, + const char *msg, ...) +{ + const char *tap_code = "ok"; + const char *directive = ""; + int saved_errno = errno; + va_list args; + + switch (exit_code) { + case KSFT_PASS: + ksft_cnt.ksft_pass++; + break; + case KSFT_XFAIL: + directive = " # XFAIL "; + ksft_cnt.ksft_xfail++; + break; + case KSFT_XPASS: + directive = " # XPASS "; + ksft_cnt.ksft_xpass++; + break; + case KSFT_SKIP: + directive = " # SKIP "; + ksft_cnt.ksft_xskip++; + break; + case KSFT_FAIL: + default: + tap_code = "not ok"; + ksft_cnt.ksft_fail++; + break; + } + + /* Docs seem to call for double space if directive is absent */ + if (!directive[0] && msg) + directive = " # "; + + printf("%s %u %s%s", tap_code, ksft_test_num(), test_name, directive); + errno = saved_errno; + if (msg) { + va_start(args, msg); + vprintf(msg, args); + va_end(args); + } + printf("\n"); +} + +/** + * ksft_test_result_report() - Report test result based on a kselftest exit code + * + * @result: a kselftest exit code + */ +#define ksft_test_result_report(result, fmt, ...) do { \ + switch (result) { \ + case KSFT_PASS: \ + ksft_test_result_pass(fmt, ##__VA_ARGS__); \ + break; \ + case KSFT_FAIL: \ + ksft_test_result_fail(fmt, ##__VA_ARGS__); \ + break; \ + case KSFT_XFAIL: \ + ksft_test_result_xfail(fmt, ##__VA_ARGS__); \ + break; \ + case KSFT_XPASS: \ + ksft_test_result_xpass(fmt, ##__VA_ARGS__); \ + break; \ + case KSFT_SKIP: \ + ksft_test_result_skip(fmt, ##__VA_ARGS__); \ + break; \ + } } while (0) + +static inline __noreturn void ksft_exit_pass(void) +{ + ksft_print_cnts(); + exit(KSFT_PASS); +} + +static inline __noreturn void ksft_exit_fail(void) +{ + ksft_print_cnts(); + exit(KSFT_FAIL); +} + +/** + * ksft_exit() - Exit selftest based on truth of condition + * + * @condition: if true, exit self test with success, otherwise fail. + */ +#define ksft_exit(condition) do { \ + if (!!(condition)) \ + ksft_exit_pass(); \ + else \ + ksft_exit_fail(); \ + } while (0) + +/** + * ksft_finished() - Exit selftest with success if all tests passed + */ +#define ksft_finished() \ + ksft_exit(ksft_plan == \ + ksft_cnt.ksft_pass + \ + ksft_cnt.ksft_xpass + \ + ksft_cnt.ksft_xfail + \ + ksft_cnt.ksft_xskip) + +static inline __noreturn __printf(1, 2) void ksft_exit_fail_msg(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + va_start(args, msg); + printf("Bail out! "); + errno = saved_errno; + vprintf(msg, args); + va_end(args); + + ksft_print_cnts(); + exit(KSFT_FAIL); +} + +static inline __noreturn void ksft_exit_fail_perror(const char *msg) +{ + ksft_exit_fail_msg("%s: %s (%d)\n", msg, strerror(errno), errno); +} + +static inline __noreturn void ksft_exit_xfail(void) +{ + ksft_print_cnts(); + exit(KSFT_XFAIL); +} + +static inline __noreturn void ksft_exit_xpass(void) +{ + ksft_print_cnts(); + exit(KSFT_XPASS); +} + +static inline __noreturn __printf(1, 2) void ksft_exit_skip(const char *msg, ...) +{ + int saved_errno = errno; + va_list args; + + va_start(args, msg); + + /* + * FIXME: several tests misuse ksft_exit_skip so produce + * something sensible if some tests have already been run + * or a plan has been printed. Those tests should use + * ksft_test_result_skip or ksft_exit_fail_msg instead. + */ + if (ksft_plan || ksft_test_num()) { + ksft_cnt.ksft_xskip++; + printf("ok %u # SKIP ", ksft_test_num()); + } else { + printf("1..0 # SKIP "); + } + if (msg) { + errno = saved_errno; + vprintf(msg, args); + va_end(args); + } + if (ksft_test_num()) + ksft_print_cnts(); + exit(KSFT_SKIP); +} + +static inline int ksft_min_kernel_version(unsigned int min_major, + unsigned int min_minor) +{ + unsigned int major, minor; + struct utsname info; + + if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2) + ksft_exit_fail_msg("Can't parse kernel version\n"); + + return major > min_major || (major == min_major && minor >= min_minor); +} + +static inline void ksft_reset_state(void) +{ + ksft_cnt.ksft_pass = 0; + ksft_cnt.ksft_fail = 0; + ksft_cnt.ksft_xfail = 0; + ksft_cnt.ksft_xpass = 0; + ksft_cnt.ksft_xskip = 0; + ksft_cnt.ksft_error = 0; + ksft_plan = 0; +} + +#endif /* __KSELFTEST_H */ -- cgit v1.3.1