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 --- tools/testing/rbtree/Makefile | 33 ++++++++++++++++++ tools/testing/rbtree/interval_tree_test.c | 58 +++++++++++++++++++++++++++++++ tools/testing/rbtree/rbtree_test.c | 48 +++++++++++++++++++++++++ tools/testing/rbtree/test.h | 4 +++ 4 files changed, 143 insertions(+) create mode 100644 tools/testing/rbtree/Makefile create mode 100644 tools/testing/rbtree/interval_tree_test.c create mode 100644 tools/testing/rbtree/rbtree_test.c create mode 100644 tools/testing/rbtree/test.h (limited to 'tools/testing/rbtree') diff --git a/tools/testing/rbtree/Makefile b/tools/testing/rbtree/Makefile new file mode 100644 index 000000000..d7bbae2af --- /dev/null +++ b/tools/testing/rbtree/Makefile @@ -0,0 +1,33 @@ +# SPDX-License-Identifier: GPL-2.0 + +.PHONY: clean + +TARGETS = rbtree_test interval_tree_test +OFILES = $(SHARED_OFILES) rbtree-shim.o interval_tree-shim.o maple-shim.o +DEPS = ../../../include/linux/rbtree.h \ + ../../../include/linux/rbtree_types.h \ + ../../../include/linux/rbtree_augmented.h \ + ../../../include/linux/interval_tree.h \ + ../../../include/linux/interval_tree_generic.h \ + ../../../lib/rbtree.c \ + ../../../lib/interval_tree.c + +targets: $(TARGETS) + +include ../shared/shared.mk + +ifeq ($(DEBUG), 1) + CFLAGS += -g +endif + +$(TARGETS): $(OFILES) + +rbtree-shim.o: $(DEPS) +rbtree_test.o: ../../../lib/rbtree_test.c +interval_tree-shim.o: $(DEPS) +interval_tree-shim.o: CFLAGS += -DCONFIG_INTERVAL_TREE_SPAN_ITER +interval_tree_test.o: ../../../lib/interval_tree_test.c +interval_tree_test.o: CFLAGS += -DCONFIG_INTERVAL_TREE_SPAN_ITER + +clean: + $(RM) $(TARGETS) *.o radix-tree.c idr.c generated/* diff --git a/tools/testing/rbtree/interval_tree_test.c b/tools/testing/rbtree/interval_tree_test.c new file mode 100644 index 000000000..49bc5b534 --- /dev/null +++ b/tools/testing/rbtree/interval_tree_test.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * interval_tree.c: Userspace Interval Tree test-suite + * Copyright (c) 2025 Wei Yang + */ +#include +#include +#include "shared.h" +#include "maple-shared.h" + +#include "../../../lib/interval_tree_test.c" + +int usage(void) +{ + fprintf(stderr, "Userland interval tree test cases\n"); + fprintf(stderr, " -n: Number of nodes in the interval tree\n"); + fprintf(stderr, " -p: Number of iterations modifying the tree\n"); + fprintf(stderr, " -q: Number of searches to the interval tree\n"); + fprintf(stderr, " -s: Number of iterations searching the tree\n"); + fprintf(stderr, " -a: Searches will iterate all nodes in the tree\n"); + fprintf(stderr, " -m: Largest value for the interval's endpoint\n"); + fprintf(stderr, " -r: Random seed\n"); + exit(-1); +} + +void interval_tree_tests(void) +{ + interval_tree_test_init(); + interval_tree_test_exit(); +} + +int main(int argc, char **argv) +{ + int opt; + + while ((opt = getopt(argc, argv, "n:p:q:s:am:r:")) != -1) { + if (opt == 'n') + nnodes = strtoul(optarg, NULL, 0); + else if (opt == 'p') + perf_loops = strtoul(optarg, NULL, 0); + else if (opt == 'q') + nsearches = strtoul(optarg, NULL, 0); + else if (opt == 's') + search_loops = strtoul(optarg, NULL, 0); + else if (opt == 'a') + search_all = true; + else if (opt == 'm') + max_endpoint = strtoul(optarg, NULL, 0); + else if (opt == 'r') + seed = strtoul(optarg, NULL, 0); + else + usage(); + } + + maple_tree_init(); + interval_tree_tests(); + return 0; +} diff --git a/tools/testing/rbtree/rbtree_test.c b/tools/testing/rbtree/rbtree_test.c new file mode 100644 index 000000000..585c970f6 --- /dev/null +++ b/tools/testing/rbtree/rbtree_test.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * rbtree_test.c: Userspace Red Black Tree test-suite + * Copyright (c) 2025 Wei Yang + */ +#include +#include +#include +#include "shared.h" + +#include "../../../lib/rbtree_test.c" + +int usage(void) +{ + fprintf(stderr, "Userland rbtree test cases\n"); + fprintf(stderr, " -n: Number of nodes in the rb-tree\n"); + fprintf(stderr, " -p: Number of iterations modifying the rb-tree\n"); + fprintf(stderr, " -c: Number of iterations modifying and verifying the rb-tree\n"); + fprintf(stderr, " -r: Random seed\n"); + exit(-1); +} + +void rbtree_tests(void) +{ + rbtree_test_init(); + rbtree_test_exit(); +} + +int main(int argc, char **argv) +{ + int opt; + + while ((opt = getopt(argc, argv, "n:p:c:r:")) != -1) { + if (opt == 'n') + nnodes = strtoul(optarg, NULL, 0); + else if (opt == 'p') + perf_loops = strtoul(optarg, NULL, 0); + else if (opt == 'c') + check_loops = strtoul(optarg, NULL, 0); + else if (opt == 'r') + seed = strtoul(optarg, NULL, 0); + else + usage(); + } + + rbtree_tests(); + return 0; +} diff --git a/tools/testing/rbtree/test.h b/tools/testing/rbtree/test.h new file mode 100644 index 000000000..f1f1b545b --- /dev/null +++ b/tools/testing/rbtree/test.h @@ -0,0 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +void rbtree_tests(void); +void interval_tree_tests(void); -- cgit v1.3.1