4 files changed, 42 insertions, 18 deletions

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 380683de1df3..8a9db38e562f 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -154,7 +154,7 @@ static double get_period_percent(struct hist_entry *he, u64 period)
 
 double perf_diff__compute_delta(struct hist_entry *he)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
         double new_percent = get_period_percent(he, he->stat.period);
         double old_percent = pair ? get_period_percent(pair, pair->stat.period) : 0.0;
 
@@ -165,7 +165,7 @@ double perf_diff__compute_delta(struct hist_entry *he)
 
 double perf_diff__compute_ratio(struct hist_entry *he)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
         double new_period = he->stat.period;
         double old_period = pair ? pair->stat.period : 0;
 
@@ -176,7 +176,7 @@ double perf_diff__compute_ratio(struct hist_entry *he)
 
 s64 perf_diff__compute_wdiff(struct hist_entry *he)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
         u64 new_period = he->stat.period;
         u64 old_period = pair ? pair->stat.period : 0;
 
@@ -193,7 +193,7 @@ s64 perf_diff__compute_wdiff(struct hist_entry *he)
 
 static int formula_delta(struct hist_entry *he, char *buf, size_t size)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
 
         if (!pair)
                 return -1;
@@ -207,7 +207,7 @@ static int formula_delta(struct hist_entry *he, char *buf, size_t size)
 
 static int formula_ratio(struct hist_entry *he, char *buf, size_t size)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
         double new_period = he->stat.period;
         double old_period = pair ? pair->stat.period : 0;
 
@@ -219,7 +219,7 @@ static int formula_ratio(struct hist_entry *he, char *buf, size_t size)
 
 static int formula_wdiff(struct hist_entry *he, char *buf, size_t size)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
         u64 new_period = he->stat.period;
         u64 old_period = pair ? pair->stat.period : 0;
 
@@ -359,8 +359,11 @@ static void hists__match(struct hists *older, struct hists *newer)
         struct rb_node *nd;
 
         for (nd = rb_first(&newer->entries); nd; nd = rb_next(nd)) {
-                struct hist_entry *pos = rb_entry(nd, struct hist_entry, rb_node);
-                pos->pair = hists__find_entry(older, pos);
+                struct hist_entry *pos = rb_entry(nd, struct hist_entry, rb_node),
+                                  *pair = hists__find_entry(older, pos);
+
+                if (pair)
+                        hist__entry_add_pair(pos, pair);
         }
 }
 
@@ -402,7 +405,7 @@ static void hists__baseline_only(struct hists *hists)
                 struct hist_entry *he = rb_entry(next, struct hist_entry, rb_node);
 
                 next = rb_next(&he->rb_node);
-                if (!he->pair) {
+                if (!hist_entry__next_pair(he)) {
                         rb_erase(&he->rb_node, &hists->entries);
                         hist_entry__free(he);
                 }
diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
index 4f5f4756faac..aa84130024d5 100644
--- a/tools/perf/ui/hist.c
+++ b/tools/perf/ui/hist.c
@@ -161,7 +161,7 @@ static int hpp__width_baseline(struct perf_hpp *hpp __maybe_unused)
 
 static double baseline_percent(struct hist_entry *he)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
         struct hists *pair_hists = pair ? pair->hists : NULL;
         double percent = 0.0;
 
@@ -179,7 +179,7 @@ static int hpp__color_baseline(struct perf_hpp *hpp, struct hist_entry *he)
 {
         double percent = baseline_percent(he);
 
-        if (he->pair)
+        if (hist_entry__has_pairs(he))
                 return percent_color_snprintf(hpp->buf, hpp->size, " %6.2f%%", percent);
         else
                 return scnprintf(hpp->buf, hpp->size, "        ");
@@ -190,7 +190,7 @@ static int hpp__entry_baseline(struct perf_hpp *hpp, struct hist_entry *he)
         double percent = baseline_percent(he);
         const char *fmt = symbol_conf.field_sep ? "%.2f" : " %6.2f%%";
 
-        if (he->pair || symbol_conf.field_sep)
+        if (hist_entry__has_pairs(he) || symbol_conf.field_sep)
                 return scnprintf(hpp->buf, hpp->size, fmt, percent);
         else
                 return scnprintf(hpp->buf, hpp->size, "            ");
@@ -248,7 +248,7 @@ static int hpp__width_period_baseline(struct perf_hpp *hpp __maybe_unused)
 
 static int hpp__entry_period_baseline(struct perf_hpp *hpp, struct hist_entry *he)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
         u64 period = pair ? pair->stat.period : 0;
         const char *fmt = symbol_conf.field_sep ? "%" PRIu64 : "%12" PRIu64;
 
@@ -354,7 +354,7 @@ static int hpp__width_displ(struct perf_hpp *hpp __maybe_unused)
 static int hpp__entry_displ(struct perf_hpp *hpp,
                             struct hist_entry *he)
 {
-        struct hist_entry *pair = he->pair;
+        struct hist_entry *pair = hist_entry__next_pair(he);
         long displacement = pair ? pair->position - he->position : 0;
         const char *fmt = symbol_conf.field_sep ? "%s" : "%6.6s";
         char buf[32] = " ";
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index a1b823f8c17f..f42de79d2e6b 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -244,6 +244,8 @@ static struct hist_entry *hist_entry__new(struct hist_entry *template)
                         he->ms.map->referenced = true;
                 if (symbol_conf.use_callchain)
                         callchain_init(he->callchain);
+
+                INIT_LIST_HEAD(&he->pairs.node);
         }
 
         return he;
diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
index 13761d83a5a0..b4e8c3ba559d 100644
--- a/tools/perf/util/sort.h
+++ b/tools/perf/util/sort.h
@@ -77,6 +77,10 @@ struct hist_entry_diff {
 struct hist_entry {
         struct rb_node          rb_node_in;
         struct rb_node          rb_node;
+        union {
+                struct list_head node;
+                struct list_head head;
+        } pairs;
         struct he_stat          stat;
         struct map_symbol       ms;
         struct thread           *thread;
@@ -96,15 +100,30 @@ struct hist_entry {
         char                    *srcline;
         struct symbol           *parent;
         unsigned long           position;
-        union {
-                struct hist_entry *pair;
-                struct rb_root    sorted_chain;
-        };
+        struct rb_root          sorted_chain;
         struct branch_info      *branch_info;
         struct hists            *hists;
         struct callchain_root   callchain[0];
 };
 
+static inline bool hist_entry__has_pairs(struct hist_entry *he)
+{
+        return !list_empty(&he->pairs.node);
+}
+
+static inline struct hist_entry *hist_entry__next_pair(struct hist_entry *he)
+{
+        if (hist_entry__has_pairs(he))
+                return list_entry(he->pairs.node.next, struct hist_entry, pairs.node);
+        return NULL;
+}
+
+static inline void hist__entry_add_pair(struct hist_entry *he,
+                                        struct hist_entry *pair)
+{
+        list_add_tail(&he->pairs.head, &pair->pairs.node);
+}
+
 enum sort_type {
         SORT_PID,
         SORT_COMM,