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Date:   Wed, 22 Sep 2021 22:59:19 +0200
From:   Jiri Olsa <jolsa@redhat.com>
To:     Ian Rogers <irogers@google.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Namhyung Kim <namhyung@kernel.org>,
        linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>,
        Jin Yao <yao.jin@linux.intel.com>,
        John Garry <john.garry@huawei.com>,
        Paul Clarke <pc@us.ibm.com>, kajoljain <kjain@linux.ibm.com>,
        linux-perf-users@vger.kernel.org,
        Stephane Eranian <eranian@google.com>,
        Sandeep Dasgupta <sdasgup@google.com>
Subject: Re: [PATCH v8 1/8] perf metric: Restructure struct expr_parse_ctx.
Message-ID: <YUuZJ/UeNv9uphy8@krava>
References: <20210918063513.2356923-1-irogers@google.com>
 <20210918063513.2356923-2-irogers@google.com>
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In-Reply-To: <20210918063513.2356923-2-irogers@google.com>
Precedence: bulk

On Fri, Sep 17, 2021 at 11:35:06PM -0700, Ian Rogers wrote:
> A later change to parsing the ids out (in expr__find_other) will
> potentially drop hashmaps and so it is more convenient to move
> expr_parse_ctx to have a hashmap pointer rather than a struct value. As
> this pointer must be freed, rather than just going out of scope,
> add expr__ctx_new and expr__ctx_free to manage expr_parse_ctx memory.
> Adjust use of struct expr_parse_ctx accordingly.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/tests/expr.c       | 81 ++++++++++++++++++-----------------
>  tools/perf/tests/pmu-events.c | 43 +++++++++++--------
>  tools/perf/util/expr.c        | 39 +++++++++++++----
>  tools/perf/util/expr.h        |  5 ++-
>  tools/perf/util/metricgroup.c | 44 ++++++++++---------
>  tools/perf/util/stat-shadow.c | 50 +++++++++++++--------
>  6 files changed, 155 insertions(+), 107 deletions(-)
> 
> diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c
> index 4d01051951cd..b0a3b5fd0c00 100644
> --- a/tools/perf/tests/expr.c
> +++ b/tools/perf/tests/expr.c
> @@ -22,67 +22,70 @@ int test__expr(struct test *t __maybe_unused, int subtest __maybe_unused)
>  	const char *p;
>  	double val;
>  	int ret;
> -	struct expr_parse_ctx ctx;
> +	struct expr_parse_ctx *ctx;
>  
> -	expr__ctx_init(&ctx);
> -	expr__add_id_val(&ctx, strdup("FOO"), 1);
> -	expr__add_id_val(&ctx, strdup("BAR"), 2);
> +	ctx = expr__ctx_new();

missing ctx check

> +	TEST_ASSERT_VAL("expr__ctx_new", ctx);
> +	expr__add_id_val(ctx, strdup("FOO"), 1);
> +	expr__add_id_val(ctx, strdup("BAR"), 2);
>  
> -	ret = test(&ctx, "1+1", 2);
> -	ret |= test(&ctx, "FOO+BAR", 3);
> -	ret |= test(&ctx, "(BAR/2)%2", 1);
> -	ret |= test(&ctx, "1 - -4",  5);
> -	ret |= test(&ctx, "(FOO-1)*2 + (BAR/2)%2 - -4",  5);
> -	ret |= test(&ctx, "1-1 | 1", 1);
> -	ret |= test(&ctx, "1-1 & 1", 0);
> -	ret |= test(&ctx, "min(1,2) + 1", 2);
> -	ret |= test(&ctx, "max(1,2) + 1", 3);
> -	ret |= test(&ctx, "1+1 if 3*4 else 0", 2);
> -	ret |= test(&ctx, "1.1 + 2.1", 3.2);
> -	ret |= test(&ctx, ".1 + 2.", 2.1);
> -	ret |= test(&ctx, "d_ratio(1, 2)", 0.5);
> -	ret |= test(&ctx, "d_ratio(2.5, 0)", 0);
> -	ret |= test(&ctx, "1.1 < 2.2", 1);
> -	ret |= test(&ctx, "2.2 > 1.1", 1);
> -	ret |= test(&ctx, "1.1 < 1.1", 0);
> -	ret |= test(&ctx, "2.2 > 2.2", 0);
> -	ret |= test(&ctx, "2.2 < 1.1", 0);
> -	ret |= test(&ctx, "1.1 > 2.2", 0);
> +	ret = test(ctx, "1+1", 2);
> +	ret |= test(ctx, "FOO+BAR", 3);
> +	ret |= test(ctx, "(BAR/2)%2", 1);
> +	ret |= test(ctx, "1 - -4",  5);
> +	ret |= test(ctx, "(FOO-1)*2 + (BAR/2)%2 - -4",  5);
> +	ret |= test(ctx, "1-1 | 1", 1);
> +	ret |= test(ctx, "1-1 & 1", 0);
> +	ret |= test(ctx, "min(1,2) + 1", 2);
> +	ret |= test(ctx, "max(1,2) + 1", 3);
> +	ret |= test(ctx, "1+1 if 3*4 else 0", 2);
> +	ret |= test(ctx, "1.1 + 2.1", 3.2);
> +	ret |= test(ctx, ".1 + 2.", 2.1);
> +	ret |= test(ctx, "d_ratio(1, 2)", 0.5);
> +	ret |= test(ctx, "d_ratio(2.5, 0)", 0);
> +	ret |= test(ctx, "1.1 < 2.2", 1);
> +	ret |= test(ctx, "2.2 > 1.1", 1);
> +	ret |= test(ctx, "1.1 < 1.1", 0);
> +	ret |= test(ctx, "2.2 > 2.2", 0);
> +	ret |= test(ctx, "2.2 < 1.1", 0);
> +	ret |= test(ctx, "1.1 > 2.2", 0);


SNIP


>  				ret++;
> @@ -876,27 +881,27 @@ static int test_parsing(void)
>  			 * make them unique.
>  			 */
>  			k = 1;
> -			hashmap__for_each_entry((&ctx.ids), cur, bkt)
> -				expr__add_id_val(&ctx, strdup(cur->key), k++);
> +			hashmap__for_each_entry(ctx->ids, cur, bkt)
> +				expr__add_id_val(ctx, strdup(cur->key), k++);
>  
> -			hashmap__for_each_entry((&ctx.ids), cur, bkt) {
> +			hashmap__for_each_entry(ctx->ids, cur, bkt) {
>  				if (check_parse_cpu(cur->key, map == cpus_map,
>  						   pe))
>  					ret++;
>  			}
>  
>  			list_for_each_entry_safe(metric, tmp, &compound_list, list) {
> -				expr__add_ref(&ctx, &metric->metric_ref);
> +				expr__add_ref(ctx, &metric->metric_ref);
>  				free(metric);
>  			}
>  
> -			if (expr__parse(&result, &ctx, pe->metric_expr, 0)) {
> +			if (expr__parse(&result, ctx, pe->metric_expr, 0)) {
>  				expr_failure("Parse failed", map, pe);
>  				ret++;
>  			}
> -			expr__ctx_clear(&ctx);
>  		}
>  	}
> +	expr__ctx_free(ctx);
>  	/* TODO: fail when not ok */
>  exit:
>  	return ret == 0 ? TEST_OK : TEST_SKIP;
> @@ -916,7 +921,7 @@ static struct test_metric metrics[] = {
>  
>  static int metric_parse_fake(const char *str)
>  {
> -	struct expr_parse_ctx ctx;
> +	struct expr_parse_ctx *ctx;
>  	struct hashmap_entry *cur;
>  	double result;
>  	int ret = -1;
> @@ -925,8 +930,8 @@ static int metric_parse_fake(const char *str)
>  
>  	pr_debug("parsing '%s'\n", str);
>  
> -	expr__ctx_init(&ctx);
> -	if (expr__find_other(str, NULL, &ctx, 0) < 0) {
> +	ctx = expr__ctx_new();

missing ctx check

jirka

> +	if (expr__find_other(str, NULL, ctx, 0) < 0) {
>  		pr_err("expr__find_other failed\n");
>  		return -1;
>  	}
> @@ -937,23 +942,23 @@ static int metric_parse_fake(const char *str)
>  	 * make them unique.
>  	 */
>  	i = 1;
> -	hashmap__for_each_entry((&ctx.ids), cur, bkt)
> -		expr__add_id_val(&ctx, strdup(cur->key), i++);
> +	hashmap__for_each_entry(ctx->ids, cur, bkt)
> +		expr__add_id_val(ctx, strdup(cur->key), i++);
>  
> -	hashmap__for_each_entry((&ctx.ids), cur, bkt) {
> +	hashmap__for_each_entry(ctx->ids, cur, bkt) {
>  		if (check_parse_fake(cur->key)) {
>  			pr_err("check_parse_fake failed\n");
>  			goto out;
>  		}
>  	}
>  
> -	if (expr__parse(&result, &ctx, str, 0))
> +	if (expr__parse(&result, ctx, str, 0))
>  		pr_err("expr__parse failed\n");
>  	else
>  		ret = 0;
>  
>  out:
> -	expr__ctx_clear(&ctx);
> +	expr__ctx_free(ctx);
>  	return ret;
>  }
>  
> diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
> index a850fd0be3ee..7b1c06772a49 100644
> --- a/tools/perf/util/expr.c
> +++ b/tools/perf/util/expr.c
> @@ -73,7 +73,7 @@ int expr__add_id(struct expr_parse_ctx *ctx, const char *id)
>  	data_ptr->parent = ctx->parent;
>  	data_ptr->kind = EXPR_ID_DATA__PARENT;
>  
> -	ret = hashmap__set(&ctx->ids, id, data_ptr,
> +	ret = hashmap__set(ctx->ids, id, data_ptr,
>  			   (const void **)&old_key, (void **)&old_data);
>  	if (ret)
>  		free(data_ptr);
> @@ -95,7 +95,7 @@ int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val)
>  	data_ptr->val = val;
>  	data_ptr->kind = EXPR_ID_DATA__VALUE;
>  
> -	ret = hashmap__set(&ctx->ids, id, data_ptr,
> +	ret = hashmap__set(ctx->ids, id, data_ptr,
>  			   (const void **)&old_key, (void **)&old_data);
>  	if (ret)
>  		free(data_ptr);
> @@ -140,7 +140,7 @@ int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref)
>  	data_ptr->ref.metric_expr = ref->metric_expr;
>  	data_ptr->kind = EXPR_ID_DATA__REF;
>  
> -	ret = hashmap__set(&ctx->ids, name, data_ptr,
> +	ret = hashmap__set(ctx->ids, name, data_ptr,
>  			   (const void **)&old_key, (void **)&old_data);
>  	if (ret)
>  		free(data_ptr);
> @@ -156,7 +156,7 @@ int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref)
>  int expr__get_id(struct expr_parse_ctx *ctx, const char *id,
>  		 struct expr_id_data **data)
>  {
> -	return hashmap__find(&ctx->ids, id, (void **)data) ? 0 : -1;
> +	return hashmap__find(ctx->ids, id, (void **)data) ? 0 : -1;
>  }
>  
>  int expr__resolve_id(struct expr_parse_ctx *ctx, const char *id,
> @@ -205,15 +205,23 @@ void expr__del_id(struct expr_parse_ctx *ctx, const char *id)
>  	struct expr_id_data *old_val = NULL;
>  	char *old_key = NULL;
>  
> -	hashmap__delete(&ctx->ids, id,
> +	hashmap__delete(ctx->ids, id,
>  			(const void **)&old_key, (void **)&old_val);
>  	free(old_key);
>  	free(old_val);
>  }
>  
> -void expr__ctx_init(struct expr_parse_ctx *ctx)
> +struct expr_parse_ctx *expr__ctx_new(void)
>  {
> -	hashmap__init(&ctx->ids, key_hash, key_equal, NULL);
> +	struct expr_parse_ctx *ctx;
> +
> +	ctx = malloc(sizeof(struct expr_parse_ctx));
> +	if (!ctx)
> +		return NULL;
> +
> +	ctx->ids = hashmap__new(key_hash, key_equal, NULL);
> +	ctx->parent = NULL;
> +	return ctx;
>  }
>  
>  void expr__ctx_clear(struct expr_parse_ctx *ctx)
> @@ -221,11 +229,24 @@ void expr__ctx_clear(struct expr_parse_ctx *ctx)
>  	struct hashmap_entry *cur;
>  	size_t bkt;
>  
> -	hashmap__for_each_entry((&ctx->ids), cur, bkt) {
> +	hashmap__for_each_entry(ctx->ids, cur, bkt) {
> +		free((char *)cur->key);
> +		free(cur->value);
> +	}
> +	hashmap__clear(ctx->ids);
> +}
> +
> +void expr__ctx_free(struct expr_parse_ctx *ctx)
> +{
> +	struct hashmap_entry *cur;
> +	size_t bkt;
> +
> +	hashmap__for_each_entry(ctx->ids, cur, bkt) {
>  		free((char *)cur->key);
>  		free(cur->value);
>  	}
> -	hashmap__clear(&ctx->ids);
> +	hashmap__free(ctx->ids);
> +	free(ctx);
>  }
>  
>  static int
> diff --git a/tools/perf/util/expr.h b/tools/perf/util/expr.h
> index 85df3e4771e4..5fa394f10418 100644
> --- a/tools/perf/util/expr.h
> +++ b/tools/perf/util/expr.h
> @@ -19,7 +19,7 @@ struct expr_id {
>  };
>  
>  struct expr_parse_ctx {
> -	struct hashmap	 ids;
> +	struct hashmap	*ids;
>  	struct expr_id	*parent;
>  };
>  
> @@ -30,8 +30,9 @@ struct expr_scanner_ctx {
>  	int runtime;
>  };
>  
> -void expr__ctx_init(struct expr_parse_ctx *ctx);
> +struct expr_parse_ctx *expr__ctx_new(void);
>  void expr__ctx_clear(struct expr_parse_ctx *ctx);
> +void expr__ctx_free(struct expr_parse_ctx *ctx);
>  void expr__del_id(struct expr_parse_ctx *ctx, const char *id);
>  int expr__add_id(struct expr_parse_ctx *ctx, const char *id);
>  int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val);
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index 29b747ac31c1..b7924a2f1f45 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -118,7 +118,7 @@ struct metric_ref_node {
>  
>  struct metric {
>  	struct list_head nd;
> -	struct expr_parse_ctx pctx;
> +	struct expr_parse_ctx *pctx;
>  	const char *metric_name;
>  	const char *metric_expr;
>  	const char *metric_unit;
> @@ -198,7 +198,7 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist,
>  	struct evsel *ev, *current_leader = NULL;
>  	struct expr_id_data *val_ptr;
>  	int i = 0, matched_events = 0, events_to_match;
> -	const int idnum = (int)hashmap__size(&pctx->ids);
> +	const int idnum = (int)hashmap__size(pctx->ids);
>  
>  	/*
>  	 * duration_time is always grouped separately, when events are grouped
> @@ -206,7 +206,7 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist,
>  	 * add it to metric_events at the end.
>  	 */
>  	if (!has_constraint &&
> -	    hashmap__find(&pctx->ids, "duration_time", (void **)&val_ptr))
> +	    hashmap__find(pctx->ids, "duration_time", (void **)&val_ptr))
>  		events_to_match = idnum - 1;
>  	else
>  		events_to_match = idnum;
> @@ -242,7 +242,7 @@ static struct evsel *find_evsel_group(struct evlist *perf_evlist,
>  		if (contains_event(metric_events, matched_events, ev->name))
>  			continue;
>  		/* Does this event belong to the parse context? */
> -		if (hashmap__find(&pctx->ids, ev->name, (void **)&val_ptr))
> +		if (hashmap__find(pctx->ids, ev->name, (void **)&val_ptr))
>  			metric_events[matched_events++] = ev;
>  
>  		if (matched_events == events_to_match)
> @@ -322,12 +322,12 @@ static int metricgroup__setup_events(struct list_head *groups,
>  		struct metric_ref *metric_refs = NULL;
>  
>  		metric_events = calloc(sizeof(void *),
> -				hashmap__size(&m->pctx.ids) + 1);
> +				hashmap__size(m->pctx->ids) + 1);
>  		if (!metric_events) {
>  			ret = -ENOMEM;
>  			break;
>  		}
> -		evsel = find_evsel_group(perf_evlist, &m->pctx,
> +		evsel = find_evsel_group(perf_evlist, m->pctx,
>  					 metric_no_merge,
>  					 m->has_constraint, metric_events,
>  					 evlist_used);
> @@ -693,7 +693,7 @@ static void metricgroup__add_metric_weak_group(struct strbuf *events,
>  	size_t bkt;
>  	bool no_group = true, has_duration = false;
>  
> -	hashmap__for_each_entry((&ctx->ids), cur, bkt) {
> +	hashmap__for_each_entry(ctx->ids, cur, bkt) {
>  		pr_debug("found event %s\n", (const char *)cur->key);
>  		/*
>  		 * Duration time maps to a software event and can make
> @@ -724,7 +724,7 @@ static void metricgroup__add_metric_non_group(struct strbuf *events,
>  	size_t bkt;
>  	bool first = true;
>  
> -	hashmap__for_each_entry((&ctx->ids), cur, bkt) {
> +	hashmap__for_each_entry(ctx->ids, cur, bkt) {
>  		if (!first)
>  			strbuf_addf(events, ",");
>  		strbuf_addf(events, "%s", (const char *)cur->key);
> @@ -799,7 +799,11 @@ static int __add_metric(struct list_head *metric_list,
>  		if (!m)
>  			return -ENOMEM;
>  
> -		expr__ctx_init(&m->pctx);
> +		m->pctx = expr__ctx_new();
> +		if (!m->pctx) {
> +			free(m);
> +			return -ENOMEM;
> +		}
>  		m->metric_name = pe->metric_name;
>  		m->metric_expr = pe->metric_expr;
>  		m->metric_unit = pe->unit;
> @@ -847,15 +851,15 @@ static int __add_metric(struct list_head *metric_list,
>  
>  	/* Force all found IDs in metric to have us as parent ID. */
>  	WARN_ON_ONCE(!parent);
> -	m->pctx.parent = parent;
> +	m->pctx->parent = parent;
>  
>  	/*
>  	 * For both the parent and referenced metrics, we parse
>  	 * all the metric's IDs and add it to the parent context.
>  	 */
> -	if (expr__find_other(pe->metric_expr, NULL, &m->pctx, runtime) < 0) {
> +	if (expr__find_other(pe->metric_expr, NULL, m->pctx, runtime) < 0) {
>  		if (m->metric_refs_cnt == 0) {
> -			expr__ctx_clear(&m->pctx);
> +			expr__ctx_free(m->pctx);
>  			free(m);
>  			*mp = NULL;
>  		}
> @@ -878,8 +882,8 @@ static int __add_metric(struct list_head *metric_list,
>  		list_for_each_prev(pos, metric_list) {
>  			struct metric *old = list_entry(pos, struct metric, nd);
>  
> -			if (hashmap__size(&m->pctx.ids) <=
> -			    hashmap__size(&old->pctx.ids))
> +			if (hashmap__size(m->pctx->ids) <=
> +			    hashmap__size(old->pctx->ids))
>  				break;
>  		}
>  		list_add(&m->nd, pos);
> @@ -927,7 +931,7 @@ static int recursion_check(struct metric *m, const char *id, struct expr_id **pa
>  	 * if we already processed 'id', if we did, it's recursion
>  	 * and we fail.
>  	 */
> -	ret = expr__get_id(&m->pctx, id, &data);
> +	ret = expr__get_id(m->pctx, id, &data);
>  	if (ret)
>  		return ret;
>  
> @@ -982,7 +986,7 @@ static int __resolve_metric(struct metric *m,
>  	 */
>  	do {
>  		all = true;
> -		hashmap__for_each_entry((&m->pctx.ids), cur, bkt) {
> +		hashmap__for_each_entry(m->pctx->ids, cur, bkt) {
>  			struct expr_id *parent;
>  			struct pmu_event *pe;
>  
> @@ -996,7 +1000,7 @@ static int __resolve_metric(struct metric *m,
>  
>  			all = false;
>  			/* The metric key itself needs to go out.. */
> -			expr__del_id(&m->pctx, cur->key);
> +			expr__del_id(m->pctx, cur->key);
>  
>  			/* ... and it gets resolved to the parent context. */
>  			ret = add_metric(metric_list, pe, metric_no_group, &m, parent, ids);
> @@ -1144,10 +1148,10 @@ static int metricgroup__add_metric(const char *metric, bool metric_no_group,
>  
>  		if (m->has_constraint) {
>  			metricgroup__add_metric_non_group(events,
> -							  &m->pctx);
> +							  m->pctx);
>  		} else {
>  			metricgroup__add_metric_weak_group(events,
> -							   &m->pctx);
> +							   m->pctx);
>  		}
>  	}
>  
> @@ -1210,7 +1214,7 @@ static void metricgroup__free_metrics(struct list_head *metric_list)
>  
>  	list_for_each_entry_safe (m, tmp, metric_list, nd) {
>  		metric__free_refs(m);
> -		expr__ctx_clear(&m->pctx);
> +		expr__ctx_free(m->pctx);
>  		list_del_init(&m->nd);
>  		free(m);
>  	}
> diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
> index 34a7f5c1fff7..c9fa07e49e72 100644
> --- a/tools/perf/util/stat-shadow.c
> +++ b/tools/perf/util/stat-shadow.c
> @@ -1,8 +1,10 @@
>  // SPDX-License-Identifier: GPL-2.0
> +#include <math.h>
>  #include <stdio.h>
>  #include "evsel.h"
>  #include "stat.h"
>  #include "color.h"
> +#include "debug.h"
>  #include "pmu.h"
>  #include "rblist.h"
>  #include "evlist.h"
> @@ -370,12 +372,16 @@ void perf_stat__collect_metric_expr(struct evlist *evsel_list)
>  {
>  	struct evsel *counter, *leader, **metric_events, *oc;
>  	bool found;
> -	struct expr_parse_ctx ctx;
> +	struct expr_parse_ctx *ctx;
>  	struct hashmap_entry *cur;
>  	size_t bkt;
>  	int i;
>  
> -	expr__ctx_init(&ctx);
> +	ctx = expr__ctx_new();
> +	if (!ctx) {
> +		pr_debug("expr__ctx_new failed");
> +		return;
> +	}
>  	evlist__for_each_entry(evsel_list, counter) {
>  		bool invalid = false;
>  
> @@ -383,25 +389,25 @@ void perf_stat__collect_metric_expr(struct evlist *evsel_list)
>  		if (!counter->metric_expr)
>  			continue;
>  
> -		expr__ctx_clear(&ctx);
> +		expr__ctx_clear(ctx);
>  		metric_events = counter->metric_events;
>  		if (!metric_events) {
>  			if (expr__find_other(counter->metric_expr,
>  					     counter->name,
> -					     &ctx, 1) < 0)
> +					     ctx, 1) < 0)
>  				continue;
>  
>  			metric_events = calloc(sizeof(struct evsel *),
> -					       hashmap__size(&ctx.ids) + 1);
> +					       hashmap__size(ctx->ids) + 1);
>  			if (!metric_events) {
> -				expr__ctx_clear(&ctx);
> +				expr__ctx_free(ctx);
>  				return;
>  			}
>  			counter->metric_events = metric_events;
>  		}
>  
>  		i = 0;
> -		hashmap__for_each_entry((&ctx.ids), cur, bkt) {
> +		hashmap__for_each_entry(ctx->ids, cur, bkt) {
>  			const char *metric_name = (const char *)cur->key;
>  
>  			found = false;
> @@ -453,7 +459,7 @@ void perf_stat__collect_metric_expr(struct evlist *evsel_list)
>  			counter->metric_expr = NULL;
>  		}
>  	}
> -	expr__ctx_clear(&ctx);
> +	expr__ctx_free(ctx);
>  }
>  
>  static double runtime_stat_avg(struct runtime_stat *st,
> @@ -818,7 +824,6 @@ static int prepare_metric(struct evsel **metric_events,
>  	char *n, *pn;
>  	int i, j, ret;
>  
> -	expr__ctx_init(pctx);
>  	for (i = 0; metric_events[i]; i++) {
>  		struct saved_value *v;
>  		struct stats *stats;
> @@ -880,17 +885,22 @@ static void generic_metric(struct perf_stat_config *config,
>  			   struct runtime_stat *st)
>  {
>  	print_metric_t print_metric = out->print_metric;
> -	struct expr_parse_ctx pctx;
> +	struct expr_parse_ctx *pctx;
>  	double ratio, scale;
>  	int i;
>  	void *ctxp = out->ctx;
>  
> -	i = prepare_metric(metric_events, metric_refs, &pctx, cpu, st);
> -	if (i < 0)
> +	pctx = expr__ctx_new();
> +	if (!pctx)
>  		return;
>  
> +	i = prepare_metric(metric_events, metric_refs, pctx, cpu, st);
> +	if (i < 0) {
> +		expr__ctx_free(pctx);
> +		return;
> +	}
>  	if (!metric_events[i]) {
> -		if (expr__parse(&ratio, &pctx, metric_expr, runtime) == 0) {
> +		if (expr__parse(&ratio, pctx, metric_expr, runtime) == 0) {
>  			char *unit;
>  			char metric_bf[64];
>  
> @@ -926,22 +936,26 @@ static void generic_metric(struct perf_stat_config *config,
>  			     (metric_name ? metric_name : name) : "", 0);
>  	}
>  
> -	expr__ctx_clear(&pctx);
> +	expr__ctx_free(pctx);
>  }
>  
>  double test_generic_metric(struct metric_expr *mexp, int cpu, struct runtime_stat *st)
>  {
> -	struct expr_parse_ctx pctx;
> +	struct expr_parse_ctx *pctx;
>  	double ratio = 0.0;
>  
> -	if (prepare_metric(mexp->metric_events, mexp->metric_refs, &pctx, cpu, st) < 0)
> +	pctx = expr__ctx_new();
> +	if (!pctx)
> +		return NAN;
> +
> +	if (prepare_metric(mexp->metric_events, mexp->metric_refs, pctx, cpu, st) < 0)
>  		goto out;
>  
> -	if (expr__parse(&ratio, &pctx, mexp->metric_expr, 1))
> +	if (expr__parse(&ratio, pctx, mexp->metric_expr, 1))
>  		ratio = 0.0;
>  
>  out:
> -	expr__ctx_clear(&pctx);
> +	expr__ctx_free(pctx);
>  	return ratio;
>  }
>  
> -- 
> 2.33.0.464.g1972c5931b-goog
>