tracing/filters: Enable filtering a scalar field by a cpumask

Several events use a scalar field to denote a CPU:
o sched_wakeup.target_cpu
o sched_migrate_task.orig_cpu,dest_cpu
o sched_move_numa.src_cpu,dst_cpu
o ipi_send_cpu.cpu
o ...

Filtering these currently requires using arithmetic comparison functions,
which can be tedious when dealing with interleaved SMT or NUMA CPU ids.

Allow these to be filtered by a user-provided cpumask, which enables e.g.:

$ trace-cmd record -e 'sched_wakeup' -f 'target_cpu & CPUS{2,4,6,8-32}'

Link: https://lkml.kernel.org/r/20230707172155.70873-4-vschneid@redhat.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Leonardo Bras <leobras@redhat.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index cb1863d..1e14f80 100644 (file)
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -46,15 +46,19 @@ static const char * ops[] = { OPS };
 enum filter_pred_fn {
        FILTER_PRED_FN_NOP,
        FILTER_PRED_FN_64,
+       FILTER_PRED_FN_64_CPUMASK,
        FILTER_PRED_FN_S64,
        FILTER_PRED_FN_U64,
        FILTER_PRED_FN_32,
+       FILTER_PRED_FN_32_CPUMASK,
        FILTER_PRED_FN_S32,
        FILTER_PRED_FN_U32,
        FILTER_PRED_FN_16,
+       FILTER_PRED_FN_16_CPUMASK,
        FILTER_PRED_FN_S16,
        FILTER_PRED_FN_U16,
        FILTER_PRED_FN_8,
+       FILTER_PRED_FN_8_CPUMASK,
        FILTER_PRED_FN_S8,
        FILTER_PRED_FN_U8,
        FILTER_PRED_FN_COMM,
@@ -643,6 +647,39 @@ out_free:
        return ERR_PTR(ret);
 }
 
+static inline int
+do_filter_cpumask(int op, const struct cpumask *mask, const struct cpumask *cmp)
+{
+       switch (op) {
+       case OP_EQ:
+               return cpumask_equal(mask, cmp);
+       case OP_NE:
+               return !cpumask_equal(mask, cmp);
+       case OP_BAND:
+               return cpumask_intersects(mask, cmp);
+       default:
+               return 0;
+       }
+}
+
+/* Optimisation of do_filter_cpumask() for scalar fields */
+static inline int
+do_filter_scalar_cpumask(int op, unsigned int cpu, const struct cpumask *mask)
+{
+       switch (op) {
+       case OP_EQ:
+               return cpumask_test_cpu(cpu, mask) &&
+                       cpumask_nth(1, mask) >= nr_cpu_ids;
+       case OP_NE:
+               return !cpumask_test_cpu(cpu, mask) ||
+                       cpumask_nth(1, mask) < nr_cpu_ids;
+       case OP_BAND:
+               return cpumask_test_cpu(cpu, mask);
+       default:
+               return 0;
+       }
+}
+
 enum pred_cmp_types {
        PRED_CMP_TYPE_NOP,
        PRED_CMP_TYPE_LT,
@@ -686,6 +723,18 @@ static int filter_pred_##type(struct filter_pred *pred, void *event)       \
        }                                                               \
 }
 
+#define DEFINE_CPUMASK_COMPARISON_PRED(size)                                   \
+static int filter_pred_##size##_cpumask(struct filter_pred *pred, void *event) \
+{                                                                              \
+       u##size *addr = (u##size *)(event + pred->offset);                      \
+       unsigned int cpu = *addr;                                               \
+                                                                               \
+       if (cpu >= nr_cpu_ids)                                                  \
+               return 0;                                                       \
+                                                                               \
+       return do_filter_scalar_cpumask(pred->op, cpu, pred->mask);             \
+}
+
 #define DEFINE_EQUALITY_PRED(size)                                     \
 static int filter_pred_##size(struct filter_pred *pred, void *event)   \
 {                                                                      \
@@ -707,6 +756,11 @@ DEFINE_COMPARISON_PRED(u16);
 DEFINE_COMPARISON_PRED(s8);
 DEFINE_COMPARISON_PRED(u8);
 
+DEFINE_CPUMASK_COMPARISON_PRED(64);
+DEFINE_CPUMASK_COMPARISON_PRED(32);
+DEFINE_CPUMASK_COMPARISON_PRED(16);
+DEFINE_CPUMASK_COMPARISON_PRED(8);
+
 DEFINE_EQUALITY_PRED(64);
 DEFINE_EQUALITY_PRED(32);
 DEFINE_EQUALITY_PRED(16);
@@ -891,16 +945,7 @@ static int filter_pred_cpumask(struct filter_pred *pred, void *event)
        const struct cpumask *mask = (event + loc);
        const struct cpumask *cmp = pred->mask;
 
-       switch (pred->op) {
-       case OP_EQ:
-               return cpumask_equal(mask, cmp);
-       case OP_NE:
-               return !cpumask_equal(mask, cmp);
-       case OP_BAND:
-               return cpumask_intersects(mask, cmp);
-       default:
-               return 0;
-       }
+       return do_filter_cpumask(pred->op, mask, cmp);
 }
 
 /* Filter predicate for COMM. */
@@ -1351,24 +1396,32 @@ static int filter_pred_fn_call(struct filter_pred *pred, void *event)
        switch (pred->fn_num) {
        case FILTER_PRED_FN_64:
                return filter_pred_64(pred, event);
+       case FILTER_PRED_FN_64_CPUMASK:
+               return filter_pred_64_cpumask(pred, event);
        case FILTER_PRED_FN_S64:
                return filter_pred_s64(pred, event);
        case FILTER_PRED_FN_U64:
                return filter_pred_u64(pred, event);
        case FILTER_PRED_FN_32:
                return filter_pred_32(pred, event);
+       case FILTER_PRED_FN_32_CPUMASK:
+               return filter_pred_32_cpumask(pred, event);
        case FILTER_PRED_FN_S32:
                return filter_pred_s32(pred, event);
        case FILTER_PRED_FN_U32:
                return filter_pred_u32(pred, event);
        case FILTER_PRED_FN_16:
                return filter_pred_16(pred, event);
+       case FILTER_PRED_FN_16_CPUMASK:
+               return filter_pred_16_cpumask(pred, event);
        case FILTER_PRED_FN_S16:
                return filter_pred_s16(pred, event);
        case FILTER_PRED_FN_U16:
                return filter_pred_u16(pred, event);
        case FILTER_PRED_FN_8:
                return filter_pred_8(pred, event);
+       case FILTER_PRED_FN_8_CPUMASK:
+               return filter_pred_8_cpumask(pred, event);
        case FILTER_PRED_FN_S8:
                return filter_pred_s8(pred, event);
        case FILTER_PRED_FN_U8:
@@ -1606,6 +1659,7 @@ static int parse_pred(const char *str, void *data,
 
                switch (field->filter_type) {
                case FILTER_CPUMASK:
+               case FILTER_OTHER:
                        break;
                default:
                        parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
@@ -1658,8 +1712,24 @@ static int parse_pred(const char *str, void *data,
 
                /* Move along */
                i++;
-               if (field->filter_type == FILTER_CPUMASK)
+               if (field->filter_type == FILTER_CPUMASK) {
                        pred->fn_num = FILTER_PRED_FN_CPUMASK;
+               } else {
+                       switch (field->size) {
+                       case 8:
+                               pred->fn_num = FILTER_PRED_FN_64_CPUMASK;
+                               break;
+                       case 4:
+                               pred->fn_num = FILTER_PRED_FN_32_CPUMASK;
+                               break;
+                       case 2:
+                               pred->fn_num = FILTER_PRED_FN_16_CPUMASK;
+                               break;
+                       case 1:
+                               pred->fn_num = FILTER_PRED_FN_8_CPUMASK;
+                               break;
+                       }
+               }
 
        /* This is either a string, or an integer */
        } else if (str[i] == '\'' || str[i] == '"') {