This patch series allows for using bpf to collect hierarchical cgroup
stats efficiently by integrating with the rstat framework. The rstat
framework provides an efficient way to collect cgroup stats percpu and
propagate them through the cgroup hierarchy.
The stats are exposed to userspace in textual form by reading files in
bpffs, similar to cgroupfs stats by using a cgroup_iter program.
cgroup_iter is a type of bpf_iter. It walks over cgroups in four modes:
- walking a cgroup's descendants in pre-order.
- walking a cgroup's descendants in post-order.
- walking a cgroup's ancestors.
- process only a single object.
If no order is specified, the default order is pre-order.
When attaching cgroup_iter, one needs to set a cgroup to the iter_link
created from attaching. This cgroup can be passed either as a file
descriptor or a cgroup id. That cgroup serves as the starting point of
the walk.
One can also terminate the walk early by returning 1 from the iter
program.
Note that because walking cgroup hierarchy holds cgroup_mutex, the iter
program is called with cgroup_mutex held.
** Background on rstat for stats collection **
(I am using a subscriber analogy that is not commonly used)
The rstat framework maintains a tree of cgroups that have updates and
which cpus have updates. A subscriber to the rstat framework maintains
their own stats. The framework is used to tell the subscriber when
and what to flush, for the most efficient stats propagation. The
workflow is as follows:
- When a subscriber updates a cgroup on a cpu, it informs the rstat
framework by calling cgroup_rstat_updated(cgrp, cpu).
- When a subscriber wants to read some stats for a cgroup, it asks
the rstat framework to initiate a stats flush (propagation) by calling
cgroup_rstat_flush(cgrp).
- When the rstat framework initiates a flush, it makes callbacks to
subscribers to aggregate stats on cpus that have updates, and
propagate updates to their parent.
Currently, the main subscribers to the rstat framework are cgroup
subsystems (e.g. memory, block). This patch series allow bpf programs to
become subscribers as well.
This patch series includes a resend of a patch from the mailing list by
Benjamin Tissoires to support sleepable kfuncs [1], modified to use the
new kfunc flags infrastructure.
Patches in this series are organized as follows:
* Patch 1 is the updated sleepable kfuncs patch.
* Patch 2 enables the use of cgroup_get_from_file() in cgroup1.
This is useful because it enables cgroup_iter to work with cgroup1, and
allows the entire stat collection workflow to be cgroup1-compatible.
* Patches 3-5 introduce cgroup_iter prog, and a selftest.
* Patches 6-8 allow bpf programs to integrate with rstat by adding the
necessary hook points and kfunc. A comprehensive selftest that
demonstrates the entire workflow for using bpf and rstat to
efficiently collect and output cgroup stats is added.
---
Changelog:
v6 -> v7:
- Updated commit/comments in cgroup_iter for read() behavior (Yonghong)
- Extracted BPF_ITER_SELF and other options out of cgroup_iter, so
that they can be used in other iters. Also renamed them. (Andrii)
- Supports both cgroup_fd and cgroup_id when specifying target cgroup.
(Andrii)
- Avoided using macro for formatting expected output in cgroup_iter
selftest. (Andrii)
- Applied 'static' on all vars and functions in cgroup_iter selftest.
(Andrii)
- Fixed broken buf reading in cgroup_iter selftest. (Andrii)
- Switched to use bpf_link__destroy() unconditionally. (Andrii)
- Removed 'volatile' for non-const global vars in selftests. (Andrii)
- Started using bpf_core_enum_value() to get memory_cgrp_id. (Andrii)
v5 -> v6:
- Rebased on bpf-next
- Tidy up cgroup_hierarchical_stats test (Andrii)
* 'static' and 'inline'
* avoid using libbpf_get_error()
* string literals of cgroup paths.
- Rename patch 8/8 to 'selftests/bpf' (Yonghong)
- Fix cgroup_iter comments (e.g. PAGE_SIZE and uapi) (Yonghong)
- Make sure further read() returns OK after previous read() finished
properly (Yonghong)
- Release cgroup_mutex before the last call of show() (Kumar)
v4 -> v5:
- Rebased on top of new kfunc flags infrastructure, updated patch 1 and
patch 6 accordingly.
- Added docs for sleepable kfuncs.
v3 -> v4:
- cgroup_iter:
* reorder fields in bpf_link_info to avoid break uapi (Yonghong)
* comment the behavior when cgroup_fd=0 (Yonghong)
* comment on the limit of number of cgroups supported by cgroup_iter.
(Yonghong)
- cgroup_hierarchical_stats selftest:
* Do not return -1 if stats are not found (causes overflow in userspace).
* Check if child process failed to join cgroup.
* Make buf and path arrays in get_cgroup_vmscan_delay() static.
* Increase the test map sizes to accomodate cgroups that are not
created by the test.
v2 -> v3:
- cgroup_iter:
* Added conditional compilation of cgroup_iter.c in kernel/bpf/Makefile
(kernel test) and dropped the !CONFIG_CGROUP patch.
* Added validation of traversal_order when attaching (Yonghong).
* Fixed previous wording "two modes" to "three modes" (Yonghong).
* Fixed the btf_dump selftest broken by this patch (Yonghong).
* Fixed ctx_arg_info[0] to use "PTR_TO_BTF_ID_OR_NULL" instead of
"PTR_TO_BTF_ID", because the "cgroup" pointer passed to iter prog can
be null.
- Use __diag_push to eliminate __weak noinline warning in
bpf_rstat_flush().
- cgroup_hierarchical_stats selftest:
* Added write_cgroup_file_parent() helper.
* Added error handling for failed map updates.
* Added null check for cgroup in vmscan_flush.
* Fixed the signature of vmscan_[start/end].
* Correctly return error code when attaching trace programs fail.
* Make sure all links are destroyed correctly and not leaking in
cgroup_hierarchical_stats selftest.
* Use memory.reclaim instead of memory.high as a more reliable way to
invoke reclaim.
* Eliminated sleeps, the test now runs faster.
v1 -> v2:
- Redesign of cgroup_iter from v1, based on Alexei's idea [2]:
* supports walking cgroup subtree.
* supports walking ancestors of a cgroup. (Andrii)
* supports terminating the walk early.
* uses fd instead of cgroup_id as parameter for iter_link. Using fd is
a convention in bpf.
* gets cgroup's ref at attach time and deref at detach.
* brought back cgroup1 support for cgroup_iter.
- Squashed the patches adding the rstat flush hook points and kfuncs
(Tejun).
- Added a comment explaining why bpf_rstat_flush() needs to be weak
(Tejun).
- Updated the final selftest with the new cgroup_iter design.
- Changed CHECKs in the selftest with ASSERTs (Yonghong, Andrii).
- Removed empty line at the end of the selftest (Yonghong).
- Renamed test files to cgroup_hierarchical_stats.c.
- Reordered CGROUP_PATH params order to match struct declaration
in the selftest (Michal).
- Removed memory_subsys_enabled() and made sure memcg controller
enablement checks make sense and are documented (Michal).
RFC v2 -> v1:
- Instead of introducing a new program type for rstat flushing, add an
empty hook point, bpf_rstat_flush(), and use fentry bpf programs to
attach to it and flush bpf stats.
- Instead of using helpers, use kfuncs for rstat functions.
- These changes simplify the patchset greatly, with minimal changes to
uapi.
RFC v1 -> RFC v2:
- Instead of rstat flush programs attach to subsystems, they now attach
to rstat (global flushers, not per-subsystem), based on discussions
with Tejun. The first patch is entirely rewritten.
- Pass cgroup pointers to rstat flushers instead of cgroup ids. This is
much more flexibility and less likely to need a uapi update later.
- rstat helpers are now only defined if CGROUP_CONFIG.
- Most of the code is now only defined if CGROUP_CONFIG and
CONFIG_BPF_SYSCALL.
- Move rstat helper protos from bpf_base_func_proto() to
tracing_prog_func_proto().
- rstat helpers argument (cgroup pointer) is now ARG_PTR_TO_BTF_ID, not
ARG_ANYTHING.
- Rewrote the selftest to use the cgroup helpers.
- Dropped bpf_map_lookup_percpu_elem (already added by Feng).
- Dropped patch to support cgroup v1 for cgroup_iter.
- Dropped patch to define some cgroup_put() when !CONFIG_CGROUP. The
code that calls it is no longer compiled when !CONFIG_CGROUP.
cgroup_iter was originally introduced in a different patch series[3].
Hao and I agreed that it fits better as part of this series.
RFC v1 of this patch series had the following changes from [3]:
- Getting the cgroup's reference at the time at attaching, instead of
at the time when iterating. (Yonghong)
- Remove .init_seq_private and .fini_seq_private callbacks for
cgroup_iter. They are not needed now. (Yonghong)
[1] https://lore.kernel.org/bpf/[email protected]/
[2] https://lore.kernel.org/bpf/20220520221919.jnqgv52k4ajlgzcl@MBP-98dd607d3435.dhcp.thefacebook.com/
[3] https://lore.kernel.org/lkml/[email protected]/
Benjamin Tissoires (1):
btf: Add a new kfunc flag which allows to mark a function to be
sleepable
Hao Luo (3):
bpf, iter: Fix the condition on p when calling stop.
bpf: Introduce cgroup iter
selftests/bpf: Test cgroup_iter.
Yosry Ahmed (4):
cgroup: enable cgroup_get_from_file() on cgroup1
cgroup: bpf: enable bpf programs to integrate with rstat
selftests/bpf: extend cgroup helpers
selftests/bpf: add a selftest for cgroup hierarchical stats collection
Documentation/bpf/kfuncs.rst | 6 +
include/linux/bpf.h | 8 +
include/linux/btf.h | 1 +
include/uapi/linux/bpf.h | 38 ++
kernel/bpf/Makefile | 3 +
kernel/bpf/bpf_iter.c | 5 +
kernel/bpf/btf.c | 9 +
kernel/bpf/cgroup_iter.c | 286 ++++++++++++++
kernel/cgroup/cgroup.c | 5 -
kernel/cgroup/rstat.c | 48 +++
tools/include/uapi/linux/bpf.h | 38 ++
tools/testing/selftests/bpf/cgroup_helpers.c | 202 ++++++++--
tools/testing/selftests/bpf/cgroup_helpers.h | 19 +-
.../selftests/bpf/prog_tests/btf_dump.c | 4 +-
.../prog_tests/cgroup_hierarchical_stats.c | 358 ++++++++++++++++++
.../selftests/bpf/prog_tests/cgroup_iter.c | 237 ++++++++++++
tools/testing/selftests/bpf/progs/bpf_iter.h | 7 +
.../bpf/progs/cgroup_hierarchical_stats.c | 226 +++++++++++
.../testing/selftests/bpf/progs/cgroup_iter.c | 39 ++
19 files changed, 1485 insertions(+), 54 deletions(-)
create mode 100644 kernel/bpf/cgroup_iter.c
create mode 100644 tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c
create mode 100644 tools/testing/selftests/bpf/prog_tests/cgroup_iter.c
create mode 100644 tools/testing/selftests/bpf/progs/cgroup_hierarchical_stats.c
create mode 100644 tools/testing/selftests/bpf/progs/cgroup_iter.c
--
2.37.1.559.g78731f0fdb-goog
From: Yosry Ahmed <[email protected]>
This patch extends bpf selft cgroup_helpers [ID] n various ways:
- Add enable_controllers() that allows tests to enable all or a
subset of controllers for a specific cgroup.
- Add join_cgroup_parent(). The cgroup workdir is based on the pid,
therefore a spawned child cannot join the same cgroup hierarchy of the
test through join_cgroup(). join_cgroup_parent() is used in child
processes to join a cgroup under the parent's workdir.
- Add write_cgroup_file() and write_cgroup_file_parent() (similar to
join_cgroup_parent() above).
- Add get_root_cgroup() for tests that need to do checks on root cgroup.
- Distinguish relative and absolute cgroup paths in function arguments.
Now relative paths are called relative_path, and absolute paths are
called cgroup_path.
Signed-off-by: Yosry Ahmed <[email protected]>
Signed-off-by: Hao Luo <[email protected]>
---
tools/testing/selftests/bpf/cgroup_helpers.c | 202 +++++++++++++++----
tools/testing/selftests/bpf/cgroup_helpers.h | 19 +-
2 files changed, 174 insertions(+), 47 deletions(-)
diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c
index 9d59c3990ca8..e914cc45b766 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.c
+++ b/tools/testing/selftests/bpf/cgroup_helpers.c
@@ -33,49 +33,52 @@
#define CGROUP_MOUNT_DFLT "/sys/fs/cgroup"
#define NETCLS_MOUNT_PATH CGROUP_MOUNT_DFLT "/net_cls"
#define CGROUP_WORK_DIR "/cgroup-test-work-dir"
-#define format_cgroup_path(buf, path) \
+
+#define format_cgroup_path_pid(buf, path, pid) \
snprintf(buf, sizeof(buf), "%s%s%d%s", CGROUP_MOUNT_PATH, \
- CGROUP_WORK_DIR, getpid(), path)
+ CGROUP_WORK_DIR, pid, path)
+
+#define format_cgroup_path(buf, path) \
+ format_cgroup_path_pid(buf, path, getpid())
+
+#define format_parent_cgroup_path(buf, path) \
+ format_cgroup_path_pid(buf, path, getppid())
#define format_classid_path(buf) \
snprintf(buf, sizeof(buf), "%s%s", NETCLS_MOUNT_PATH, \
CGROUP_WORK_DIR)
-/**
- * enable_all_controllers() - Enable all available cgroup v2 controllers
- *
- * Enable all available cgroup v2 controllers in order to increase
- * the code coverage.
- *
- * If successful, 0 is returned.
- */
-static int enable_all_controllers(char *cgroup_path)
+static int __enable_controllers(const char *cgroup_path, const char *controllers)
{
char path[PATH_MAX + 1];
- char buf[PATH_MAX];
+ char enable[PATH_MAX + 1];
char *c, *c2;
int fd, cfd;
ssize_t len;
- snprintf(path, sizeof(path), "%s/cgroup.controllers", cgroup_path);
- fd = open(path, O_RDONLY);
- if (fd < 0) {
- log_err("Opening cgroup.controllers: %s", path);
- return 1;
- }
-
- len = read(fd, buf, sizeof(buf) - 1);
- if (len < 0) {
+ /* If not controllers are passed, enable all available controllers */
+ if (!controllers) {
+ snprintf(path, sizeof(path), "%s/cgroup.controllers",
+ cgroup_path);
+ fd = open(path, O_RDONLY);
+ if (fd < 0) {
+ log_err("Opening cgroup.controllers: %s", path);
+ return 1;
+ }
+ len = read(fd, enable, sizeof(enable) - 1);
+ if (len < 0) {
+ close(fd);
+ log_err("Reading cgroup.controllers: %s", path);
+ return 1;
+ } else if (len == 0) { /* No controllers to enable */
+ close(fd);
+ return 0;
+ }
+ enable[len] = 0;
close(fd);
- log_err("Reading cgroup.controllers: %s", path);
- return 1;
+ } else {
+ strncpy(enable, controllers, sizeof(enable));
}
- buf[len] = 0;
- close(fd);
-
- /* No controllers available? We're probably on cgroup v1. */
- if (len == 0)
- return 0;
snprintf(path, sizeof(path), "%s/cgroup.subtree_control", cgroup_path);
cfd = open(path, O_RDWR);
@@ -84,7 +87,7 @@ static int enable_all_controllers(char *cgroup_path)
return 1;
}
- for (c = strtok_r(buf, " ", &c2); c; c = strtok_r(NULL, " ", &c2)) {
+ for (c = strtok_r(enable, " ", &c2); c; c = strtok_r(NULL, " ", &c2)) {
if (dprintf(cfd, "+%s\n", c) <= 0) {
log_err("Enabling controller %s: %s", c, path);
close(cfd);
@@ -95,6 +98,87 @@ static int enable_all_controllers(char *cgroup_path)
return 0;
}
+/**
+ * enable_controllers() - Enable cgroup v2 controllers
+ * @relative_path: The cgroup path, relative to the workdir
+ * @controllers: List of controllers to enable in cgroup.controllers format
+ *
+ *
+ * Enable given cgroup v2 controllers, if @controllers is NULL, enable all
+ * available controllers.
+ *
+ * If successful, 0 is returned.
+ */
+int enable_controllers(const char *relative_path, const char *controllers)
+{
+ char cgroup_path[PATH_MAX + 1];
+
+ format_cgroup_path(cgroup_path, relative_path);
+ return __enable_controllers(cgroup_path, controllers);
+}
+
+static int __write_cgroup_file(const char *cgroup_path, const char *file,
+ const char *buf)
+{
+ char file_path[PATH_MAX + 1];
+ int fd;
+
+ snprintf(file_path, sizeof(file_path), "%s/%s", cgroup_path, file);
+ fd = open(file_path, O_RDWR);
+ if (fd < 0) {
+ log_err("Opening %s", file_path);
+ return 1;
+ }
+
+ if (dprintf(fd, "%s", buf) <= 0) {
+ log_err("Writing to %s", file_path);
+ close(fd);
+ return 1;
+ }
+ close(fd);
+ return 0;
+}
+
+/**
+ * write_cgroup_file() - Write to a cgroup file
+ * @relative_path: The cgroup path, relative to the workdir
+ * @file: The name of the file in cgroupfs to write to
+ * @buf: Buffer to write to the file
+ *
+ * Write to a file in the given cgroup's directory.
+ *
+ * If successful, 0 is returned.
+ */
+int write_cgroup_file(const char *relative_path, const char *file,
+ const char *buf)
+{
+ char cgroup_path[PATH_MAX - 24];
+
+ format_cgroup_path(cgroup_path, relative_path);
+ return __write_cgroup_file(cgroup_path, file, buf);
+}
+
+/**
+ * write_cgroup_file_parent() - Write to a cgroup file in the parent process
+ * workdir
+ * @relative_path: The cgroup path, relative to the parent process workdir
+ * @file: The name of the file in cgroupfs to write to
+ * @buf: Buffer to write to the file
+ *
+ * Write to a file in the given cgroup's directory under the parent process
+ * workdir.
+ *
+ * If successful, 0 is returned.
+ */
+int write_cgroup_file_parent(const char *relative_path, const char *file,
+ const char *buf)
+{
+ char cgroup_path[PATH_MAX - 24];
+
+ format_parent_cgroup_path(cgroup_path, relative_path);
+ return __write_cgroup_file(cgroup_path, file, buf);
+}
+
/**
* setup_cgroup_environment() - Setup the cgroup environment
*
@@ -133,7 +217,9 @@ int setup_cgroup_environment(void)
return 1;
}
- if (enable_all_controllers(cgroup_workdir))
+ /* Enable all available controllers to increase test coverage */
+ if (__enable_controllers(CGROUP_MOUNT_PATH, NULL) ||
+ __enable_controllers(cgroup_workdir, NULL))
return 1;
return 0;
@@ -173,7 +259,7 @@ static int join_cgroup_from_top(const char *cgroup_path)
/**
* join_cgroup() - Join a cgroup
- * @path: The cgroup path, relative to the workdir, to join
+ * @relative_path: The cgroup path, relative to the workdir, to join
*
* This function expects a cgroup to already be created, relative to the cgroup
* work dir, and it joins it. For example, passing "/my-cgroup" as the path
@@ -182,11 +268,27 @@ static int join_cgroup_from_top(const char *cgroup_path)
*
* On success, it returns 0, otherwise on failure it returns 1.
*/
-int join_cgroup(const char *path)
+int join_cgroup(const char *relative_path)
+{
+ char cgroup_path[PATH_MAX + 1];
+
+ format_cgroup_path(cgroup_path, relative_path);
+ return join_cgroup_from_top(cgroup_path);
+}
+
+/**
+ * join_parent_cgroup() - Join a cgroup in the parent process workdir
+ * @relative_path: The cgroup path, relative to parent process workdir, to join
+ *
+ * See join_cgroup().
+ *
+ * On success, it returns 0, otherwise on failure it returns 1.
+ */
+int join_parent_cgroup(const char *relative_path)
{
char cgroup_path[PATH_MAX + 1];
- format_cgroup_path(cgroup_path, path);
+ format_parent_cgroup_path(cgroup_path, relative_path);
return join_cgroup_from_top(cgroup_path);
}
@@ -212,9 +314,27 @@ void cleanup_cgroup_environment(void)
nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT);
}
+/**
+ * get_root_cgroup() - Get the FD of the root cgroup
+ *
+ * On success, it returns the file descriptor. On failure, it returns -1.
+ * If there is a failure, it prints the error to stderr.
+ */
+int get_root_cgroup(void)
+{
+ int fd;
+
+ fd = open(CGROUP_MOUNT_PATH, O_RDONLY);
+ if (fd < 0) {
+ log_err("Opening root cgroup");
+ return -1;
+ }
+ return fd;
+}
+
/**
* create_and_get_cgroup() - Create a cgroup, relative to workdir, and get the FD
- * @path: The cgroup path, relative to the workdir, to join
+ * @relative_path: The cgroup path, relative to the workdir, to join
*
* This function creates a cgroup under the top level workdir and returns the
* file descriptor. It is idempotent.
@@ -222,14 +342,14 @@ void cleanup_cgroup_environment(void)
* On success, it returns the file descriptor. On failure it returns -1.
* If there is a failure, it prints the error to stderr.
*/
-int create_and_get_cgroup(const char *path)
+int create_and_get_cgroup(const char *relative_path)
{
char cgroup_path[PATH_MAX + 1];
int fd;
- format_cgroup_path(cgroup_path, path);
+ format_cgroup_path(cgroup_path, relative_path);
if (mkdir(cgroup_path, 0777) && errno != EEXIST) {
- log_err("mkdiring cgroup %s .. %s", path, cgroup_path);
+ log_err("mkdiring cgroup %s .. %s", relative_path, cgroup_path);
return -1;
}
@@ -244,13 +364,13 @@ int create_and_get_cgroup(const char *path)
/**
* get_cgroup_id() - Get cgroup id for a particular cgroup path
- * @path: The cgroup path, relative to the workdir, to join
+ * @relative_path: The cgroup path, relative to the workdir, to join
*
* On success, it returns the cgroup id. On failure it returns 0,
* which is an invalid cgroup id.
* If there is a failure, it prints the error to stderr.
*/
-unsigned long long get_cgroup_id(const char *path)
+unsigned long long get_cgroup_id(const char *relative_path)
{
int dirfd, err, flags, mount_id, fhsize;
union {
@@ -261,7 +381,7 @@ unsigned long long get_cgroup_id(const char *path)
struct file_handle *fhp, *fhp2;
unsigned long long ret = 0;
- format_cgroup_path(cgroup_workdir, path);
+ format_cgroup_path(cgroup_workdir, relative_path);
dirfd = AT_FDCWD;
flags = 0;
diff --git a/tools/testing/selftests/bpf/cgroup_helpers.h b/tools/testing/selftests/bpf/cgroup_helpers.h
index fcc9cb91b211..3358734356ab 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.h
+++ b/tools/testing/selftests/bpf/cgroup_helpers.h
@@ -10,11 +10,18 @@
__FILE__, __LINE__, clean_errno(), ##__VA_ARGS__)
/* cgroupv2 related */
-int cgroup_setup_and_join(const char *path);
-int create_and_get_cgroup(const char *path);
-unsigned long long get_cgroup_id(const char *path);
-
-int join_cgroup(const char *path);
+int enable_controllers(const char *relative_path, const char *controllers);
+int write_cgroup_file(const char *relative_path, const char *file,
+ const char *buf);
+int write_cgroup_file_parent(const char *relative_path, const char *file,
+ const char *buf);
+int cgroup_setup_and_join(const char *relative_path);
+int get_root_cgroup(void);
+int create_and_get_cgroup(const char *relative_path);
+unsigned long long get_cgroup_id(const char *relative_path);
+
+int join_cgroup(const char *relative_path);
+int join_parent_cgroup(const char *relative_path);
int setup_cgroup_environment(void);
void cleanup_cgroup_environment(void);
@@ -26,4 +33,4 @@ int join_classid(void);
int setup_classid_environment(void);
void cleanup_classid_environment(void);
-#endif /* __CGROUP_HELPERS_H */
\ No newline at end of file
+#endif /* __CGROUP_HELPERS_H */
--
2.37.1.559.g78731f0fdb-goog
Hello:
This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <[email protected]>:
On Fri, 5 Aug 2022 14:48:13 -0700 you wrote:
> This patch series allows for using bpf to collect hierarchical cgroup
> stats efficiently by integrating with the rstat framework. The rstat
> framework provides an efficient way to collect cgroup stats percpu and
> propagate them through the cgroup hierarchy.
>
> The stats are exposed to userspace in textual form by reading files in
> bpffs, similar to cgroupfs stats by using a cgroup_iter program.
> cgroup_iter is a type of bpf_iter. It walks over cgroups in four modes:
> - walking a cgroup's descendants in pre-order.
> - walking a cgroup's descendants in post-order.
> - walking a cgroup's ancestors.
> - process only a single object.
>
> [...]
Here is the summary with links:
- [bpf-next,v7,1/8] btf: Add a new kfunc flag which allows to mark a function to be sleepable
https://git.kernel.org/bpf/bpf-next/c/fa96b24204af
- [bpf-next,v7,2/8] cgroup: enable cgroup_get_from_file() on cgroup1
https://git.kernel.org/bpf/bpf-next/c/f3a2aebdd6fb
- [bpf-next,v7,3/8] bpf, iter: Fix the condition on p when calling stop.
https://git.kernel.org/bpf/bpf-next/c/be3bb83dab2d
- [bpf-next,v7,4/8] bpf: Introduce cgroup iter
(no matching commit)
- [bpf-next,v7,5/8] selftests/bpf: Test cgroup_iter.
(no matching commit)
- [bpf-next,v7,6/8] cgroup: bpf: enable bpf programs to integrate with rstat
(no matching commit)
- [bpf-next,v7,7/8] selftests/bpf: extend cgroup helpers
(no matching commit)
- [bpf-next,v7,8/8] selftests/bpf: add a selftest for cgroup hierarchical stats collection
(no matching commit)
You are awesome, thank you!
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