[PATCH 1/2] perf:tools: avoid to create much more maps for kernel symbols on ARM

[PATCH 1/2] perf:tools: avoid to create much more maps for kernel symbols on ARM

[tom.leiming]

From: Ming Lei <tom.leiming@gmail.com>

On ARM, module addresss space is ahead of kernel space,
so the module symbols are handled before kernel symbol
in dso__split_kallsyms, then cause one map is created
for each kernel symbol.

This patch fixes the issue by restoring to original kernel
map in dso__split_kallsyms() to avoid create unnecessary maps
for kernel symbols when starting to handle kenel symbol maps
but after module symbol maps are handled over.

Cc: Ian Munsie <imunsie@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
 tools/perf/util/symbol.c |   58 ++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 58 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 0500895..c5b4ccb 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -520,6 +520,53 @@ static int dso__load_all_kallsyms(struct dso *self, const char *filename,
 	return kallsyms__parse(filename, &args, map__process_kallsym_symbol);
 }
 
+static int map_for_module(struct map *map, struct machine *self)
+{
+	char *line = NULL;
+	FILE *file;
+	const char *modules;
+	char name[PATH_MAX];
+	int ret = 0;
+
+	if (machine__is_default_guest(self))
+		modules = symbol_conf.default_guest_modules;
+	else {
+		sprintf(name, "%s/proc/modules", self->root_dir);
+		modules = name;
+	}
+
+	file = fopen(modules, "r");
+	if (file == NULL)
+		return ret;
+
+	/*strip [] of map->dso->short_name*/
+	strncpy(name, map->dso->short_name + 1,
+			strlen(map->dso->short_name) - 2);
+	name[strlen(map->dso->short_name) - 3] = '\0';
+
+	while (!feof(file)) {
+		int line_len;
+		size_t n;
+
+		line_len = getline(&line, &n, file);
+		if (line_len < 0)
+			break;
+
+		if (!line)
+			break;
+
+		line[line_len-1] = '\0'; /* \n */
+
+		if (strstr(line, name)) {
+			ret = 1;
+			break;
+		}
+	}
+
+	free(line);
+	fclose(file);
+	return ret;
+}
 /*
  * Split the symbols into maps, making sure there are no overlaps, i.e. the
  * kernel range is broken in several maps, named [kernel].N, as we don't have
@@ -590,6 +637,16 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
 			char dso_name[PATH_MAX];
 			struct dso *dso;
 
+			/*
+			 * If module symbol is ahead of kernel symbol like ARM,
+			 * restore to original kernel map to avoid create many
+			 * unnecessary maps for kernel symbols.
+			 */
+			if (map_for_module(curr_map, machine)) {
+				curr_map = map;
+				goto operate_map;
+			}
+
 			if (self->kernel == DSO_TYPE_GUEST_KERNEL)
 				snprintf(dso_name, sizeof(dso_name),
 					"[guest.kernel].%d",
@@ -616,6 +673,7 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
 			++kernel_range;
 		}
 
+operate_map:
 		if (filter && filter(curr_map, pos)) {
 discard_symbol:		rb_erase(&pos->rb_node, root);
 			symbol__delete(pos);
-- 
1.7.3

Re: [PATCH 1/2] perf:tools: avoid to create much more maps for kernel symbols on ARM

[Arnaldo Carvalho de Melo]

Em Wed, Nov 24, 2010 at 07:35:02PM +0800, tom.leiming@gmail.com escreveu:
> From: Ming Lei <tom.leiming@gmail.com>
 
> On ARM, module addresss space is ahead of kernel space, so the module
> symbols are handled before kernel symbol in dso__split_kallsyms, then
> cause one map is created for each kernel symbol.
 
> This patch fixes the issue by restoring to original kernel map in
> dso__split_kallsyms() to avoid create unnecessary maps for kernel
> symbols when starting to handle kenel symbol maps but after module
> symbol maps are handled over.

Can you try with the following patch instead?

- Arnaldo

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index b39f499..a7518d2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -530,7 +530,7 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
 	struct machine *machine = kmaps->machine;
 	struct map *curr_map = map;
 	struct symbol *pos;
-	int count = 0;
+	int count = 0, moved = 0;	
 	struct rb_root *root = &self->symbols[map->type];
 	struct rb_node *next = rb_first(root);
 	int kernel_range = 0;
@@ -588,6 +588,11 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
 			char dso_name[PATH_MAX];
 			struct dso *dso;
 
+			if (count == 0) {
+				curr_map = map;
+				goto filter_symbol;
+			}
+
 			if (self->kernel == DSO_TYPE_GUEST_KERNEL)
 				snprintf(dso_name, sizeof(dso_name),
 					"[guest.kernel].%d",
@@ -613,7 +618,7 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
 			map_groups__insert(kmaps, curr_map);
 			++kernel_range;
 		}
-
+filter_symbol:
 		if (filter && filter(curr_map, pos)) {
 discard_symbol:		rb_erase(&pos->rb_node, root);
 			symbol__delete(pos);
@@ -621,8 +626,9 @@ discard_symbol:		rb_erase(&pos->rb_node, root);
 			if (curr_map != map) {
 				rb_erase(&pos->rb_node, root);
 				symbols__insert(&curr_map->dso->symbols[curr_map->type], pos);
-			}
-			count++;
+				++moved;
+			} else
+				++count;
 		}
 	}
 
@@ -632,7 +638,7 @@ discard_symbol:		rb_erase(&pos->rb_node, root);
 		dso__set_loaded(curr_map->dso, curr_map->type);
 	}
 
-	return count;
+	return count + moved;
 }
 
 int dso__load_kallsyms(struct dso *self, const char *filename,

Re: [PATCH 1/2] perf:tools: avoid to create much more maps for kernel symbols on ARM

[Ming Lei]

2010/11/24 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>:
> Em Wed, Nov 24, 2010 at 07:35:02PM +0800, tom.leiming@gmail.com escreveu:
>> From: Ming Lei <tom.leiming@gmail.com>
>
>> On ARM, module addresss space is ahead of kernel space, so the module
>> symbols are handled before kernel symbol in dso__split_kallsyms, then
>> cause one map is created for each kernel symbol.
>
>> This patch fixes the issue by restoring to original kernel map in
>> dso__split_kallsyms() to avoid create unnecessary maps for kernel
>> symbols when starting to handle kenel symbol maps but after module
>> symbol maps are handled over.
>
> Can you try with the following patch instead?

Fine to me.

Reported-and-tested-by: Ming Lei <tom.leiming@gmail.com>

>
> - Arnaldo
>
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index b39f499..a7518d2 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -530,7 +530,7 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
>        struct machine *machine = kmaps->machine;
>        struct map *curr_map = map;
>        struct symbol *pos;
> -       int count = 0;
> +       int count = 0, moved = 0;
>        struct rb_root *root = &self->symbols[map->type];
>        struct rb_node *next = rb_first(root);
>        int kernel_range = 0;
> @@ -588,6 +588,11 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
>                        char dso_name[PATH_MAX];
>                        struct dso *dso;
>
> +                       if (count == 0) {
> +                               curr_map = map;
> +                               goto filter_symbol;
> +                       }
> +
>                        if (self->kernel == DSO_TYPE_GUEST_KERNEL)
>                                snprintf(dso_name, sizeof(dso_name),
>                                        "[guest.kernel].%d",
> @@ -613,7 +618,7 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
>                        map_groups__insert(kmaps, curr_map);
>                        ++kernel_range;
>                }
> -
> +filter_symbol:
>                if (filter && filter(curr_map, pos)) {
>  discard_symbol:                rb_erase(&pos->rb_node, root);
>                        symbol__delete(pos);
> @@ -621,8 +626,9 @@ discard_symbol:             rb_erase(&pos->rb_node, root);
>                        if (curr_map != map) {
>                                rb_erase(&pos->rb_node, root);
>                                symbols__insert(&curr_map->dso->symbols[curr_map->type], pos);
> -                       }
> -                       count++;
> +                               ++moved;
> +                       } else
> +                               ++count;
>                }
>        }
>
> @@ -632,7 +638,7 @@ discard_symbol:             rb_erase(&pos->rb_node, root);
>                dso__set_loaded(curr_map->dso, curr_map->type);
>        }
>
> -       return count;
> +       return count + moved;
>  }
>
>  int dso__load_kallsyms(struct dso *self, const char *filename,
>

thanks,
-- 
Lei Ming

Re: [PATCH 1/2] perf:tools: avoid to create much more maps for kernel symbols on ARM

[Ming Lei]

2010/11/25 Ming Lei <tom.leiming@gmail.com>:
> 2010/11/24 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>:
>> Em Wed, Nov 24, 2010 at 07:35:02PM +0800, tom.leiming@gmail.com escreveu:
>>> From: Ming Lei <tom.leiming@gmail.com>
>>
>>> On ARM, module addresss space is ahead of kernel space, so the module
>>> symbols are handled before kernel symbol in dso__split_kallsyms, then
>>> cause one map is created for each kernel symbol.
>>
>>> This patch fixes the issue by restoring to original kernel map in
>>> dso__split_kallsyms() to avoid create unnecessary maps for kernel
>>> symbols when starting to handle kenel symbol maps but after module
>>> symbol maps are handled over.
>>
>> Can you try with the following patch instead?
>
> Fine to me.
>
> Reported-and-tested-by: Ming Lei <tom.leiming@gmail.com>

Arnaldo, could you queue this one and the patch below

      http://marc.info/?l=linux-kernel&m=129068448714210&w=2

into your tree? Without the two, perf tool can't work well on ARM
if there are modules loaded.

thanks,
-- 
Lei Ming

[tip:perf/urgent] perf symbols: Fix kallsyms kernel/module map splitting

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  8a9533123f43f2cdb3eb601c17ff2ad336882eff
Gitweb:     http://git.kernel.org/tip/8a9533123f43f2cdb3eb601c17ff2ad336882eff
Author:     Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Mon, 29 Nov 2010 12:44:15 -0200
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 30 Nov 2010 14:47:51 -0200

perf symbols: Fix kallsyms kernel/module map splitting

On ARM, module addresss space is ahead of kernel space, so the module
symbols are handled before kernel symbol in dso__split_kallsyms, then
was causing one map to be created for each kernel symbol.

Reported-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Ming Lei <tom.leiming@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20101124144540.GB15875@ghostprotocols.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/symbol.c |   16 +++++++++++-----
 1 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 0500895..2af4d7d 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -532,7 +532,7 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
 	struct machine *machine = kmaps->machine;
 	struct map *curr_map = map;
 	struct symbol *pos;
-	int count = 0;
+	int count = 0, moved = 0;	
 	struct rb_root *root = &self->symbols[map->type];
 	struct rb_node *next = rb_first(root);
 	int kernel_range = 0;
@@ -590,6 +590,11 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
 			char dso_name[PATH_MAX];
 			struct dso *dso;
 
+			if (count == 0) {
+				curr_map = map;
+				goto filter_symbol;
+			}
+
 			if (self->kernel == DSO_TYPE_GUEST_KERNEL)
 				snprintf(dso_name, sizeof(dso_name),
 					"[guest.kernel].%d",
@@ -615,7 +620,7 @@ static int dso__split_kallsyms(struct dso *self, struct map *map,
 			map_groups__insert(kmaps, curr_map);
 			++kernel_range;
 		}
-
+filter_symbol:
 		if (filter && filter(curr_map, pos)) {
 discard_symbol:		rb_erase(&pos->rb_node, root);
 			symbol__delete(pos);
@@ -623,8 +628,9 @@ discard_symbol:		rb_erase(&pos->rb_node, root);
 			if (curr_map != map) {
 				rb_erase(&pos->rb_node, root);
 				symbols__insert(&curr_map->dso->symbols[curr_map->type], pos);
-			}
-			count++;
+				++moved;
+			} else
+				++count;
 		}
 	}
 
@@ -634,7 +640,7 @@ discard_symbol:		rb_erase(&pos->rb_node, root);
 		dso__set_loaded(curr_map->dso, curr_map->type);
 	}
 
-	return count;
+	return count + moved;
 }
 
 int dso__load_kallsyms(struct dso *self, const char *filename,