linux-kernel - [PATCH 6/9] perf tools: Don't search for active kernel start in __machine__create_kernel

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Message-Id: <20180215122635.24029-7-jolsa@kernel.org>
Date:   Thu, 15 Feb 2018 13:26:32 +0100
From:   Jiri Olsa <jolsa@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        David Ahern <dsahern@...il.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: [PATCH 6/9] perf tools: Don't search for active kernel start in __machine__create_kernel_maps

We should not search for kernel start address in
__machine__create_kernel_maps function, because it's being
used in 'report' code path, where we are interested in kernel
MMAP data address instead of in current kernel address

The __machine__create_kernel_maps serves purely for creating
the machines kernel maps and setting up the kmap group. The
report code path then sets the address based on the data from
kernel MMAP event in machine__set_kernel_mmap function.

The kallsyms search address logic is used for test code, that
calls machine__create_kernel_maps to get current maps and calls
machine__get_running_kernel_start to get kernel starting address.

Using machine__set_kernel_mmap to se the kernel maps start
address and moving map_groups__fixup_end to be call when
all maps are in place.

Also making __machine__create_kernel_maps static, because there's
no external user.

Link: http://lkml.kernel.org/n/tip-37lmdjzh8dwq03golnk7hgkd@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 tools/perf/util/machine.c | 55 ++++++++++++++++++++++-------------------------
 tools/perf/util/machine.h |  1 -
 2 files changed, 26 insertions(+), 30 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 292e70c774bd..2db8d7dd0f80 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -856,13 +856,10 @@ static int machine__get_running_kernel_start(struct machine *machine,
 	return 0;
 }
 
-int __machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
+static int
+__machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
 {
 	int type;
-	u64 start = 0;
-
-	if (machine__get_running_kernel_start(machine, NULL, &start))
-		return -1;
 
 	/* In case of renewal the kernel map, destroy previous one */
 	machine__destroy_kernel_maps(machine);
@@ -871,7 +868,7 @@ int __machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
 		struct kmap *kmap;
 		struct map *map;
 
-		machine->vmlinux_maps[type] = map__new2(start, kernel, type);
+		machine->vmlinux_maps[type] = map__new2(0, kernel, type);
 		if (machine->vmlinux_maps[type] == NULL)
 			return -1;
 
@@ -1222,6 +1219,24 @@ static int machine__create_modules(struct machine *machine)
 	return 0;
 }
 
+static void machine__set_kernel_mmap(struct machine *machine,
+				     u64 start, u64 end)
+{
+	int i;
+
+	for (i = 0; i < MAP__NR_TYPES; i++) {
+		machine->vmlinux_maps[i]->start = start;
+		machine->vmlinux_maps[i]->end   = end;
+
+		/*
+		 * Be a bit paranoid here, some perf.data file came with
+		 * a zero sized synthesized MMAP event for the kernel.
+		 */
+		if (machine->vmlinux_maps[i]->end == 0)
+			machine->vmlinux_maps[i]->end = ~0ULL;
+	}
+}
+
 int machine__create_kernel_maps(struct machine *machine)
 {
 	struct dso *kernel = machine__get_kernel(machine);
@@ -1246,40 +1261,22 @@ int machine__create_kernel_maps(struct machine *machine)
 				 "continuing anyway...\n", machine->pid);
 	}
 
-	/*
-	 * Now that we have all the maps created, just set the ->end of them:
-	 */
-	map_groups__fixup_end(&machine->kmaps);
-
 	if (!machine__get_running_kernel_start(machine, &name, &addr)) {
 		if (name &&
 		    maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, addr)) {
 			machine__destroy_kernel_maps(machine);
 			return -1;
 		}
+		machine__set_kernel_mmap(machine, addr, 0);
 	}
 
+	/*
+	 * Now that we have all the maps created, just set the ->end of them:
+	 */
+	map_groups__fixup_end(&machine->kmaps);
 	return 0;
 }
 
-static void machine__set_kernel_mmap(struct machine *machine,
-				     u64 start, u64 end)
-{
-	int i;
-
-	for (i = 0; i < MAP__NR_TYPES; i++) {
-		machine->vmlinux_maps[i]->start = start;
-		machine->vmlinux_maps[i]->end   = end;
-
-		/*
-		 * Be a bit paranoid here, some perf.data file came with
-		 * a zero sized synthesized MMAP event for the kernel.
-		 */
-		if (machine->vmlinux_maps[i]->end == 0)
-			machine->vmlinux_maps[i]->end = ~0ULL;
-	}
-}
-
 static bool machine__uses_kcore(struct machine *machine)
 {
 	struct dso *dso;
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index cb0a20f3a96b..50d587d34459 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -238,7 +238,6 @@ size_t machines__fprintf_dsos_buildid(struct machines *machines, FILE *fp,
 				     bool (skip)(struct dso *dso, int parm), int parm);
 
 void machine__destroy_kernel_maps(struct machine *machine);
-int __machine__create_kernel_maps(struct machine *machine, struct dso *kernel);
 int machine__create_kernel_maps(struct machine *machine);
 
 int machines__create_kernel_maps(struct machines *machines, pid_t pid);
-- 
2.13.6