From a9e3760b0838299649c0d57cca44daaf40ba3c33 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 14 Sep 2026 22:12:34 -1000 Subject: sched_ext: Maintain an online cid mask in the scheduler arena Schedulers on the default cid mapping treat [0, nr_online_cids) as the online set and restart on hotplug. Schedulers that install their own mapping with scx_bpf_cid_override() have no way to learn which cids are online: the count no longer identifies members and the CPU-form cpumask is unusable from cid programs. This is an obvious hole in the cid API. Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's arena, allocated alongside the per-CPU scratch masks and populated after the cid mapping is finalized and before ops.init(), for child schedulers too. The pointer stays valid through ops.exit() with no reference to take. It is the arena offset as a void pointer, the same form struct_ops arena arguments arrive in. The verifier types the void return as a scalar for the program's arena cast. The mask follows the SCX hotplug notifications: seeded from cpu_active_mask and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask only inside a hotplug transition. Updates walk the scheduler list under the lock that also serializes unlinking. Reads are live, not atomic snapshots. Root initialization excludes hotplug. v2: Reworded the getter kerneldoc (Andrea Righi). Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- lib/atomic64_test.c | 277 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 277 insertions(+) create mode 100644 lib/atomic64_test.c (limited to 'lib/atomic64_test.c') diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c new file mode 100644 index 000000000..d72606835 --- /dev/null +++ b/lib/atomic64_test.c @@ -0,0 +1,277 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Testsuite for atomic64_t functions + * + * Copyright © 2010 Luca Barbieri + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include + +#ifdef CONFIG_X86 +#include /* for boot_cpu_has below */ +#endif + +#define TEST(bit, op, c_op, val) \ +do { \ + atomic##bit##_set(&v, v0); \ + r = v0; \ + atomic##bit##_##op(val, &v); \ + r c_op val; \ + WARN(atomic##bit##_read(&v) != r, "%Lx != %Lx\n", \ + (unsigned long long)atomic##bit##_read(&v), \ + (unsigned long long)r); \ +} while (0) + +/* + * Test for a atomic operation family, + * @test should be a macro accepting parameters (bit, op, ...) + */ + +#define FAMILY_TEST(test, bit, op, args...) \ +do { \ + test(bit, op, ##args); \ + test(bit, op##_acquire, ##args); \ + test(bit, op##_release, ##args); \ + test(bit, op##_relaxed, ##args); \ +} while (0) + +#define TEST_RETURN(bit, op, c_op, val) \ +do { \ + atomic##bit##_set(&v, v0); \ + r = v0; \ + r c_op val; \ + BUG_ON(atomic##bit##_##op(val, &v) != r); \ + BUG_ON(atomic##bit##_read(&v) != r); \ +} while (0) + +#define TEST_FETCH(bit, op, c_op, val) \ +do { \ + atomic##bit##_set(&v, v0); \ + r = v0; \ + r c_op val; \ + BUG_ON(atomic##bit##_##op(val, &v) != v0); \ + BUG_ON(atomic##bit##_read(&v) != r); \ +} while (0) + +#define RETURN_FAMILY_TEST(bit, op, c_op, val) \ +do { \ + FAMILY_TEST(TEST_RETURN, bit, op, c_op, val); \ +} while (0) + +#define FETCH_FAMILY_TEST(bit, op, c_op, val) \ +do { \ + FAMILY_TEST(TEST_FETCH, bit, op, c_op, val); \ +} while (0) + +#define TEST_ARGS(bit, op, init, ret, expect, args...) \ +do { \ + atomic##bit##_set(&v, init); \ + BUG_ON(atomic##bit##_##op(&v, ##args) != ret); \ + BUG_ON(atomic##bit##_read(&v) != expect); \ +} while (0) + +#define XCHG_FAMILY_TEST(bit, init, new) \ +do { \ + FAMILY_TEST(TEST_ARGS, bit, xchg, init, init, new, new); \ +} while (0) + +#define CMPXCHG_FAMILY_TEST(bit, init, new, wrong) \ +do { \ + FAMILY_TEST(TEST_ARGS, bit, cmpxchg, \ + init, init, new, init, new); \ + FAMILY_TEST(TEST_ARGS, bit, cmpxchg, \ + init, init, init, wrong, new); \ +} while (0) + +#define INC_RETURN_FAMILY_TEST(bit, i) \ +do { \ + FAMILY_TEST(TEST_ARGS, bit, inc_return, \ + i, (i) + one, (i) + one); \ +} while (0) + +#define DEC_RETURN_FAMILY_TEST(bit, i) \ +do { \ + FAMILY_TEST(TEST_ARGS, bit, dec_return, \ + i, (i) - one, (i) - one); \ +} while (0) + +static __init void test_atomic(void) +{ + int v0 = 0xaaa31337; + int v1 = 0xdeadbeef; + int onestwos = 0x11112222; + int one = 1; + + atomic_t v; + int r; + + TEST(, add, +=, onestwos); + TEST(, add, +=, -one); + TEST(, sub, -=, onestwos); + TEST(, sub, -=, -one); + TEST(, or, |=, v1); + TEST(, and, &=, v1); + TEST(, xor, ^=, v1); + TEST(, andnot, &= ~, v1); + + RETURN_FAMILY_TEST(, add_return, +=, onestwos); + RETURN_FAMILY_TEST(, add_return, +=, -one); + RETURN_FAMILY_TEST(, sub_return, -=, onestwos); + RETURN_FAMILY_TEST(, sub_return, -=, -one); + + FETCH_FAMILY_TEST(, fetch_add, +=, onestwos); + FETCH_FAMILY_TEST(, fetch_add, +=, -one); + FETCH_FAMILY_TEST(, fetch_sub, -=, onestwos); + FETCH_FAMILY_TEST(, fetch_sub, -=, -one); + + FETCH_FAMILY_TEST(, fetch_or, |=, v1); + FETCH_FAMILY_TEST(, fetch_and, &=, v1); + FETCH_FAMILY_TEST(, fetch_andnot, &= ~, v1); + FETCH_FAMILY_TEST(, fetch_xor, ^=, v1); + + INC_RETURN_FAMILY_TEST(, v0); + DEC_RETURN_FAMILY_TEST(, v0); + + XCHG_FAMILY_TEST(, v0, v1); + CMPXCHG_FAMILY_TEST(, v0, v1, onestwos); + +} + +#define INIT(c) do { atomic64_set(&v, c); r = c; } while (0) +static __init void test_atomic64(void) +{ + long long v0 = 0xaaa31337c001d00dLL; + long long v1 = 0xdeadbeefdeafcafeLL; + long long v2 = 0xfaceabadf00df001LL; + long long v3 = 0x8000000000000000LL; + long long onestwos = 0x1111111122222222LL; + long long one = 1LL; + int r_int; + + atomic64_t v = ATOMIC64_INIT(v0); + long long r = v0; + BUG_ON(v.counter != r); + + atomic64_set(&v, v1); + r = v1; + BUG_ON(v.counter != r); + BUG_ON(atomic64_read(&v) != r); + + TEST(64, add, +=, onestwos); + TEST(64, add, +=, -one); + TEST(64, sub, -=, onestwos); + TEST(64, sub, -=, -one); + TEST(64, or, |=, v1); + TEST(64, and, &=, v1); + TEST(64, xor, ^=, v1); + TEST(64, andnot, &= ~, v1); + + RETURN_FAMILY_TEST(64, add_return, +=, onestwos); + RETURN_FAMILY_TEST(64, add_return, +=, -one); + RETURN_FAMILY_TEST(64, sub_return, -=, onestwos); + RETURN_FAMILY_TEST(64, sub_return, -=, -one); + + FETCH_FAMILY_TEST(64, fetch_add, +=, onestwos); + FETCH_FAMILY_TEST(64, fetch_add, +=, -one); + FETCH_FAMILY_TEST(64, fetch_sub, -=, onestwos); + FETCH_FAMILY_TEST(64, fetch_sub, -=, -one); + + FETCH_FAMILY_TEST(64, fetch_or, |=, v1); + FETCH_FAMILY_TEST(64, fetch_and, &=, v1); + FETCH_FAMILY_TEST(64, fetch_andnot, &= ~, v1); + FETCH_FAMILY_TEST(64, fetch_xor, ^=, v1); + + INIT(v0); + atomic64_inc(&v); + r += one; + BUG_ON(v.counter != r); + + INIT(v0); + atomic64_dec(&v); + r -= one; + BUG_ON(v.counter != r); + + INC_RETURN_FAMILY_TEST(64, v0); + DEC_RETURN_FAMILY_TEST(64, v0); + + XCHG_FAMILY_TEST(64, v0, v1); + CMPXCHG_FAMILY_TEST(64, v0, v1, v2); + + INIT(v0); + BUG_ON(atomic64_add_unless(&v, one, v0)); + BUG_ON(v.counter != r); + + INIT(v0); + BUG_ON(!atomic64_add_unless(&v, one, v1)); + r += one; + BUG_ON(v.counter != r); + + INIT(onestwos); + BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1)); + r -= one; + BUG_ON(v.counter != r); + + INIT(0); + BUG_ON(atomic64_dec_if_positive(&v) != -one); + BUG_ON(v.counter != r); + + INIT(-one); + BUG_ON(atomic64_dec_if_positive(&v) != (-one - one)); + BUG_ON(v.counter != r); + + INIT(onestwos); + BUG_ON(!atomic64_inc_not_zero(&v)); + r += one; + BUG_ON(v.counter != r); + + INIT(0); + BUG_ON(atomic64_inc_not_zero(&v)); + BUG_ON(v.counter != r); + + INIT(-one); + BUG_ON(!atomic64_inc_not_zero(&v)); + r += one; + BUG_ON(v.counter != r); + + /* Confirm the return value fits in an int, even if the value doesn't */ + INIT(v3); + r_int = atomic64_inc_not_zero(&v); + BUG_ON(!r_int); +} + +static __init int test_atomics_init(void) +{ + test_atomic(); + test_atomic64(); + +#ifdef CONFIG_X86 + pr_info("passed for %s platform %s CX8 and %s SSE\n", +#ifdef CONFIG_X86_64 + "x86-64", +#elif defined(CONFIG_X86_CX8) + "i586+", +#else + "i386+", +#endif + boot_cpu_has(X86_FEATURE_CX8) ? "with" : "without", + boot_cpu_has(X86_FEATURE_XMM) ? "with" : "without"); +#else + pr_info("passed\n"); +#endif + + return 0; +} + +static __exit void test_atomics_exit(void) {} + +module_init(test_atomics_init); +module_exit(test_atomics_exit); + +MODULE_DESCRIPTION("Testsuite for atomic64_t functions"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1