[tip:,sched/core] selftests/rseq: Implement rseq numa node id field selftest
Commit Message
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 99babd04b25054717d21840298b0b46046b42cd9
Gitweb: https://git.kernel.org/tip/99babd04b25054717d21840298b0b46046b42cd9
Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
AuthorDate: Tue, 22 Nov 2022 15:39:08 -05:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 27 Dec 2022 12:52:11 +01:00
selftests/rseq: Implement rseq numa node id field selftest
Test the NUMA node id extension rseq field. Compare it against the value
returned by the getcpu(2) system call while pinned on a specific core.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-7-mathieu.desnoyers@efficios.com
---
tools/testing/selftests/rseq/basic_test.c | 4 +++-
tools/testing/selftests/rseq/rseq-abi.h | 8 ++++++-
tools/testing/selftests/rseq/rseq.c | 18 ++++++++++++++-
tools/testing/selftests/rseq/rseq.h | 28 ++++++++++++++++++++++-
4 files changed, 58 insertions(+)
@@ -22,6 +22,8 @@ void test_cpu_pointer(void)
CPU_ZERO(&test_affinity);
for (i = 0; i < CPU_SETSIZE; i++) {
if (CPU_ISSET(i, &affinity)) {
+ int node;
+
CPU_SET(i, &test_affinity);
sched_setaffinity(0, sizeof(test_affinity),
&test_affinity);
@@ -29,6 +31,8 @@ void test_cpu_pointer(void)
assert(rseq_current_cpu() == i);
assert(rseq_current_cpu_raw() == i);
assert(rseq_cpu_start() == i);
+ node = rseq_fallback_current_node();
+ assert(rseq_current_node_id() == node);
CPU_CLR(i, &test_affinity);
}
}
@@ -148,6 +148,14 @@ struct rseq_abi {
__u32 flags;
/*
+ * Restartable sequences node_id field. Updated by the kernel. Read by
+ * user-space with single-copy atomicity semantics. This field should
+ * only be read by the thread which registered this data structure.
+ * Aligned on 32-bit. Contains the current NUMA node ID.
+ */
+ __u32 node_id;
+
+ /*
* Flexible array member at end of structure, after last feature field.
*/
char end[];
@@ -79,6 +79,11 @@ static int sys_rseq(struct rseq_abi *rseq_abi, uint32_t rseq_len,
return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
}
+static int sys_getcpu(unsigned *cpu, unsigned *node)
+{
+ return syscall(__NR_getcpu, cpu, node, NULL);
+}
+
int rseq_available(void)
{
int rc;
@@ -201,3 +206,16 @@ int32_t rseq_fallback_current_cpu(void)
}
return cpu;
}
+
+int32_t rseq_fallback_current_node(void)
+{
+ uint32_t cpu_id, node_id;
+ int ret;
+
+ ret = sys_getcpu(&cpu_id, &node_id);
+ if (ret) {
+ perror("sys_getcpu()");
+ return ret;
+ }
+ return (int32_t) node_id;
+}
@@ -20,6 +20,15 @@
#include "rseq-abi.h"
#include "compiler.h"
+#ifndef rseq_sizeof_field
+#define rseq_sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
+#endif
+
+#ifndef rseq_offsetofend
+#define rseq_offsetofend(TYPE, MEMBER) \
+ (offsetof(TYPE, MEMBER) + rseq_sizeof_field(TYPE, MEMBER))
+#endif
+
/*
* Empty code injection macros, override when testing.
* It is important to consider that the ASM injection macros need to be
@@ -129,6 +138,11 @@ int rseq_unregister_current_thread(void);
int32_t rseq_fallback_current_cpu(void);
/*
+ * Restartable sequence fallback for reading the current node number.
+ */
+int32_t rseq_fallback_current_node(void);
+
+/*
* Values returned can be either the current CPU number, -1 (rseq is
* uninitialized), or -2 (rseq initialization has failed).
*/
@@ -163,6 +177,20 @@ static inline uint32_t rseq_current_cpu(void)
return cpu;
}
+static inline bool rseq_node_id_available(void)
+{
+ return (int) rseq_feature_size >= rseq_offsetofend(struct rseq_abi, node_id);
+}
+
+/*
+ * Current NUMA node number.
+ */
+static inline uint32_t rseq_current_node_id(void)
+{
+ assert(rseq_node_id_available());
+ return RSEQ_ACCESS_ONCE(rseq_get_abi()->node_id);
+}
+
static inline void rseq_clear_rseq_cs(void)
{
RSEQ_WRITE_ONCE(rseq_get_abi()->rseq_cs.arch.ptr, 0);