[RFC PATCH 03/14] tracing/filters: Enable filtering a scalar field by a cpumask
From: Valentin Schneider <vschneid@redhat.com>
Date: 2023-07-05 18:17:21
Also in:
bpf, kvm, linux-mm, linux-trace-kernel, lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
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 & MASK{2,4,6,8-32}'
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
NOTE: I went with an implicit cpumask conversion of the event field, as
AFAICT predicate_parse() does not support parsing the application of a
function to a field (e.g. 'MASK(target_cpu) & MASK{2,4,6,8-32}')
---
kernel/trace/trace_events_filter.c | 92 ++++++++++++++++++++++++++----
1 file changed, 80 insertions(+), 12 deletions(-)
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 8af00caa363f7..99e111c237a93 100644
--- 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,
@@ -641,6 +645,37 @@ predicate_parse(const char *str, int nr_parens, int nr_preds, 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 values */ +static inline int +do_filter_cpumask_scalar(int op, unsigned int cpu, const struct cpumask *mask) +{ + switch (op) { + case OP_EQ: + return cpumask_equal(mask, cpumask_of(cpu)); + case OP_NE: + return !cpumask_equal(mask, cpumask_of(cpu)); + case OP_BAND: + return cpumask_test_cpu(cpu, mask); + default: + return 0; + } +} + enum pred_cmp_types { PRED_CMP_TYPE_NOP, PRED_CMP_TYPE_LT,
@@ -684,6 +719,18 @@ 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_cpumask_scalar(pred->op, cpu, pred->mask); \ +} + #define DEFINE_EQUALITY_PRED(size) \ static int filter_pred_##size(struct filter_pred *pred, void *event) \ { \
@@ -705,6 +752,11 @@ 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);
@@ -889,16 +941,7 @@ 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. */
@@ -1349,24 +1392,32 @@ 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:
@@ -1602,7 +1653,8 @@ static int parse_pred(const char *str, void *data, unsigned int maskstart; char *tmp; - if (field->filter_type != FILTER_CPUMASK) { + if (field->filter_type != FILTER_CPUMASK && + field->filter_type != FILTER_OTHER) { parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i); goto err_free; }
@@ -1644,8 +1696,24 @@ 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] == '"') {
--
2.31.1