For task and task_file bpf iterators, optional 'task main_thread_only'
can signal the kernel to only iterate through main threads of each
process. link_query will also print out main_thread_only value for
task/task_file iterators.
This patch also fixed the issue where if the additional arguments
are not supported, bpftool will print an error message and exit.
$ ./bpftool iter pin ./bpf_iter_task.o /sys/fs/bpf/p1 task main_thread_only
$ ./bpftool iter pin ./bpf_iter_task_file.o /sys/fs/bpf/p2 task
main_thread_only
$ ./bpftool iter pin ./bpf_iter_task_file.o /sys/fs/bpf/p3
$ ./bpftool link show
1: iter prog 6 target_name bpf_map
2: iter prog 7 target_name bpf_prog
3: iter prog 12 target_name task main_thread_only 1
5: iter prog 23 target_name task_file main_thread_only 1
6: iter prog 28 target_name task_file main_thread_only 0
$ cat /sys/fs/bpf/p2
tgid gid fd file
...
1716 1716 255 ffffffffa2e95ec0
1756 1756 0 ffffffffa2e95ec0
1756 1756 1 ffffffffa2e95ec0
1756 1756 2 ffffffffa2e95ec0
1756 1756 3 ffffffffa2e20a80
1756 1756 4 ffffffffa2e19ba0
1756 1756 5 ffffffffa2e16460
1756 1756 6 ffffffffa2e16460
1756 1756 7 ffffffffa2e16460
1756 1756 8 ffffffffa2e16260
1761 1761 0 ffffffffa2e95ec0
...
$ ls /proc/1756/task/
1756 1757 1758 1759 1760
In the above task_file iterator, the process with id 1756 has 5 threads and
only the thread with pid = 1756 is processed by the bpf program.
Signed-off-by: Yonghong Song <y...@fb.com>
---
.../bpftool/Documentation/bpftool-iter.rst | 17 +++++++++--
tools/bpf/bpftool/bash-completion/bpftool | 9 +++++-
tools/bpf/bpftool/iter.c | 28 ++++++++++++++++---
tools/bpf/bpftool/link.c | 12 ++++++++
4 files changed, 59 insertions(+), 7 deletions(-)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-iter.rst
b/tools/bpf/bpftool/Documentation/bpftool-iter.rst
index 070ffacb42b5..d9aac12c76da 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-iter.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-iter.rst
@@ -17,15 +17,16 @@ SYNOPSIS
ITER COMMANDS
===================
-| **bpftool** **iter pin** *OBJ* *PATH* [**map** *MAP*]
+| **bpftool** **iter pin** *OBJ* *PATH* [**map** *MAP* | **task**
*TASK_OPT*]
| **bpftool** **iter help**
|
| *OBJ* := /a/file/of/bpf_iter_target.o
| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
+| *TASK_OPT* := { **main_thread_only** }
DESCRIPTION
===========
- **bpftool iter pin** *OBJ* *PATH* [**map** *MAP*]
+ **bpftool iter pin** *OBJ* *PATH* [**map** *MAP* | **task** *TASK_OPT*]
A bpf iterator combines a kernel iterating of
particular kernel data (e.g., tasks, bpf_maps, etc.)
and a bpf program called for each kernel data object
@@ -44,6 +45,11 @@ DESCRIPTION
with each map element, do checking, filtering, aggregation,
etc. without copying data to user space.
+ The task or task_file bpf iterator can have an optional
+ parameter *TASK_OPT*. The current supported value is
+ **main_thread_only** which supports to iterate only main
+ threads of each process.
+
User can then *cat PATH* to see the bpf iterator output.
**bpftool iter help**
@@ -78,6 +84,13 @@ EXAMPLES
Create a file-based bpf iterator from bpf_iter_hashmap.o and map with
id 20, and pin it to /sys/fs/bpf/my_hashmap
+**# bpftool iter pin bpf_iter_task.o /sys/fs/bpf/my_task task
main_thread_only**
+
+::
+
+ Create a file-based bpf iterator from bpf_iter_task.o which iterates main
+ threads of processes only, and pin it to /sys/fs/bpf/my_hashmap
+
SEE ALSO
========
**bpf**\ (2),
diff --git a/tools/bpf/bpftool/bash-completion/bpftool
b/tools/bpf/bpftool/bash-completion/bpftool
index 7b68e3c0a5fb..84d538de71e1 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -613,6 +613,7 @@ _bpftool()
esac
;;
iter)
+ local TARGET_TYPE='map task'
case $command in
pin)
case $prev in
@@ -628,9 +629,15 @@ _bpftool()
pinned)
_filedir
;;
- *)
+ task)
+ _bpftool_one_of_list 'main_thread_only'
+ ;;
+ map)
_bpftool_one_of_list $MAP_TYPE
;;
+ *)
+ _bpftool_one_of_list $TARGET_TYPE
+ ;;
esac
return 0
;;
diff --git a/tools/bpf/bpftool/iter.c b/tools/bpf/bpftool/iter.c
index 3b1aad7535dd..a4c789ea43f1 100644
--- a/tools/bpf/bpftool/iter.c
+++ b/tools/bpf/bpftool/iter.c
@@ -26,6 +26,7 @@ static int do_pin(int argc, char **argv)
/* optional arguments */
if (argc) {
+ memset(&linfo, 0, sizeof(linfo));
if (is_prefix(*argv, "map")) {
NEXT_ARG();
@@ -38,11 +39,29 @@ static int do_pin(int argc, char **argv)
if (map_fd < 0)
return -1;
- memset(&linfo, 0, sizeof(linfo));
linfo.map.map_fd = map_fd;
- iter_opts.link_info = &linfo;
- iter_opts.link_info_len = sizeof(linfo);
+ } else if (is_prefix(*argv, "task")) {
+ NEXT_ARG();
+
+ if (!REQ_ARGS(1)) {
+ p_err("incorrect task spec");
+ return -1;
+ }
+
+ if (strcmp(*argv, "main_thread_only") != 0) {
+ p_err("incorrect task spec");
+ return -1;
+ }
+
+ linfo.task.main_thread_only = true;
+ } else {
+ p_err("expected no more arguments, 'map' or 'task',
got: '%s'?",
+ *argv);
+ return -1;
}
+
+ iter_opts.link_info = &linfo;
+ iter_opts.link_info_len = sizeof(linfo);
}
obj = bpf_object__open(objfile);
@@ -95,9 +114,10 @@ static int do_pin(int argc, char **argv)
static int do_help(int argc, char **argv)
{
fprintf(stderr,
- "Usage: %1$s %2$s pin OBJ PATH [map MAP]\n"
+ "Usage: %1$s %2$s pin OBJ PATH [map MAP | task TASK_OPT]\n"
" %1$s %2$s help\n"
" " HELP_SPEC_MAP "\n"
+ " TASK_OPT := { main_thread_only }\n"
"",
bin_name, "iter");
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index e77e1525d20a..a159d5680c74 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -83,6 +83,12 @@ static bool is_iter_map_target(const char *target_name)
strcmp(target_name, "bpf_sk_storage_map") == 0;
}
+static bool is_iter_task_target(const char *target_name)
+{
+ return strcmp(target_name, "task") == 0 ||
+ strcmp(target_name, "task_file") == 0;
+}
+
static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
{
const char *target_name = u64_to_ptr(info->iter.target_name);
@@ -91,6 +97,9 @@ static void show_iter_json(struct bpf_link_info *info,
json_writer_t *wtr)
if (is_iter_map_target(target_name))
jsonw_uint_field(wtr, "map_id", info->iter.map.map_id);
+ else if (is_iter_task_target(target_name))
+ jsonw_uint_field(wtr, "main_thread_only",
+ info->iter.task.main_thread_only);
}
static int get_prog_info(int prog_id, struct bpf_prog_info *info)
@@ -202,6 +211,9 @@ static void show_iter_plain(struct bpf_link_info *info)
if (is_iter_map_target(target_name))
printf("map_id %u ", info->iter.map.map_id);
+ else if (is_iter_task_target(target_name))
+ printf("main_thread_only %u ",
+ info->iter.task.main_thread_only);
}
static int show_link_close_plain(int fd, struct bpf_link_info *info)
--
2.24.1
