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From: Jiri Olsa <jolsa@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>,
	lkml <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Stanislav Fomichev <sdf@fomichev.me>,
	Song Liu <songliubraving@fb.com>, Andi Kleen <ak@linux.intel.com>
Subject: [PATCH 08/12] perf tools: Preserve eBPF maps when loading kcore
Date: Wed,  8 May 2019 15:20:06 +0200
Message-ID: <20190508132010.14512-9-jolsa@kernel.org> (raw)
In-Reply-To: <20190508132010.14512-1-jolsa@kernel.org>

We need to preserve eBPF maps even if they are
covered by kcore, because we need to access
eBPF dso for source data.

Adding map_groups__merge_in function to do that.
It merges map into map_groups by splitting the
new map within the existing map regions.

Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/n/tip-mlu13e9zl6rbsz4fa00x7mfa@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/util/symbol.c | 97 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 93 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 5cbad55cd99d..29780fcd049c 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1166,6 +1166,85 @@ static int kcore_mapfn(u64 start, u64 len, u64 pgoff, void *data)
 	return 0;
 }
 
+/*
+ * Merges map into map_groups by splitting the new map
+ * within the existing map regions.
+ */
+static int map_groups__merge_in(struct map_groups *kmaps, struct map *new_map)
+{
+	struct map *old_map;
+	LIST_HEAD(merged);
+
+	for (old_map = map_groups__first(kmaps); old_map;
+	     old_map = map_groups__next(old_map)) {
+
+		/* no overload with this one */
+		if (new_map->end < old_map->start ||
+		    new_map->start >= old_map->end)
+			continue;
+
+		if (new_map->start < old_map->start) {
+			/*
+			 * |new......
+			 *       |old....
+			 */
+			if (new_map->end < old_map->end) {
+				/*
+				 * |new......|     -> |new..|
+				 *       |old....| ->       |old....|
+				 */
+				new_map->end = old_map->start;
+			} else {
+				/*
+				 * |new.............| -> |new..|       |new..|
+				 *       |old....|    ->       |old....|
+				 */
+				struct map *m = map__clone(new_map);
+
+				if (!m)
+					return -ENOMEM;
+
+				m->end = old_map->start;
+				list_add_tail(&m->node, &merged);
+				new_map->start = old_map->end;
+			}
+		} else {
+			/*
+			 *      |new......
+			 * |old....
+			 */
+			if (new_map->end < old_map->end) {
+				/*
+				 *      |new..|   -> x
+				 * |old.........| -> |old.........|
+				 */
+				map__put(new_map);
+				new_map = NULL;
+				break;
+			} else {
+				/*
+				 *      |new......| ->         |new...|
+				 * |old....|        -> |old....|
+				 */
+				new_map->start = old_map->end;
+			}
+		}
+	}
+
+	while (!list_empty(&merged)) {
+		old_map = list_entry(merged.next, struct map, node);
+		list_del_init(&old_map->node);
+		map_groups__insert(kmaps, old_map);
+		map__put(old_map);
+	}
+
+	if (new_map) {
+		map_groups__insert(kmaps, new_map);
+		map__put(new_map);
+	}
+	return 0;
+}
+
 static int dso__load_kcore(struct dso *dso, struct map *map,
 			   const char *kallsyms_filename)
 {
@@ -1222,7 +1301,12 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 	while (old_map) {
 		struct map *next = map_groups__next(old_map);
 
-		if (old_map != map)
+		/*
+		 * We need to preserve eBPF maps even if they are
+		 * covered by kcore, because we need to access
+		 * eBPF dso for source data.
+		 */
+		if (old_map != map && !__map__is_bpf_prog(old_map))
 			map_groups__remove(kmaps, old_map);
 		old_map = next;
 	}
@@ -1256,11 +1340,16 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 			map_groups__remove(kmaps, map);
 			map_groups__insert(kmaps, map);
 			map__put(map);
+			map__put(new_map);
 		} else {
-			map_groups__insert(kmaps, new_map);
+			/*
+			 * Merge kcore map into existing maps,
+			 * and ensure that current maps (eBPF)
+			 * stay intact.
+			 */
+			if (map_groups__merge_in(kmaps, new_map))
+				goto out_err;
 		}
-
-		map__put(new_map);
 	}
 
 	if (machine__is(machine, "x86_64")) {
-- 
2.20.1


  parent reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-08 13:19 [PATCHv3 00/12] perf tools: Display eBPF code in intel_pt trace Jiri Olsa
2019-05-08 13:19 ` [PATCH 01/12] perf tools: Separate generic code in dso__data_file_size Jiri Olsa
2019-05-13 19:47   ` Arnaldo Carvalho de Melo
2019-05-13 20:00     ` Jiri Olsa
2019-05-23  3:10       ` Namhyung Kim
2019-05-23  7:49         ` Jiri Olsa
2019-05-30  8:08   ` [tip:perf/core] perf dso: Separate generic code in dso__data_file_size() tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 02/12] perf tools: Separate generic code in dso_cache__read Jiri Olsa
2019-05-30  8:09   ` [tip:perf/core] perf dso: " tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 03/12] perf tools: Simplify dso_cache__read function Jiri Olsa
2019-05-30  8:09   ` [tip:perf/core] perf dso: " tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 04/12] perf tools: Add bpf dso read and size hooks Jiri Olsa
2019-05-30  8:10   ` [tip:perf/core] perf dso: Add BPF DSO " tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 05/12] perf tools: Read also the end of the kernel Jiri Olsa
2019-05-24 18:15   ` Arnaldo Carvalho de Melo
2019-05-24 18:17     ` Arnaldo Carvalho de Melo
2019-05-24 18:46       ` Arnaldo Carvalho de Melo
2019-05-26 13:09         ` Jiri Olsa
2019-05-24 23:21     ` Jiri Olsa
2019-05-28 21:29   ` [tip:perf/urgent] perf machine: " tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 06/12] perf tools: Keep zero in pgoff bpf map Jiri Olsa
2019-05-30  7:55   ` [tip:perf/core] perf machine: Keep zero in pgoff BPF map tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 07/12] perf script: Pad dso name for --call-trace Jiri Olsa
2019-05-30  8:11   ` [tip:perf/core] perf script: Pad DSO " tip-bot for Jiri Olsa
2019-05-08 13:20 ` Jiri Olsa [this message]
2019-05-22 16:06   ` [PATCH 08/12] perf tools: Preserve eBPF maps when loading kcore Arnaldo Carvalho de Melo
2019-05-22 21:22     ` Jiri Olsa
2019-05-30  7:56   ` [tip:perf/core] " tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 09/12] perf tests: Add map_groups__merge_in test Jiri Olsa
2019-05-30  8:11   ` [tip:perf/core] " tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 10/12] perf script: Add --show-bpf-events to show eBPF related events Jiri Olsa
2019-05-30  8:12   ` [tip:perf/core] " tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 11/12] perf script: Remove superfluous bpf event titles Jiri Olsa
2019-05-30  8:13   ` [tip:perf/core] perf script: Remove superfluous BPF " tip-bot for Jiri Olsa
2019-05-08 13:20 ` [PATCH 12/12] perf script: Add --show-all-events option Jiri Olsa
2019-05-22 16:18   ` Arnaldo Carvalho de Melo
2019-05-22 21:30     ` Jiri Olsa
2019-05-08 21:49 ` [PATCHv3 00/12] perf tools: Display eBPF code in intel_pt trace Song Liu
2019-05-08 23:41   ` Arnaldo Carvalho de Melo
2019-05-24  0:27 ` Arnaldo Carvalho de Melo
2019-05-24 10:06   ` Jiri Olsa
2019-05-30 10:54 ` Leo Yan
2019-05-30 12:07   ` Jiri Olsa
2019-05-30 12:57     ` Leo Yan
2019-05-30 13:27       ` Jiri Olsa
2019-05-30 13:36       ` Arnaldo Carvalho de Melo
2019-05-30 14:05         ` Leo Yan
2019-05-31  9:19           ` Jiri Olsa
2019-06-02  6:42             ` Leo Yan
2019-05-31  9:09         ` Leo Yan
  -- strict thread matches above, loose matches on Subject: below --
2019-05-03  8:18 [PATCHv2 " Jiri Olsa
2019-05-03  8:18 ` [PATCH 08/12] perf tools: Preserve eBPF maps when loading kcore Jiri Olsa

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