| Message ID | 20230830230126.260508-2-namhyung@kernel.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | perf lock contention: Add cgroup support (v1) | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
Em Wed, Aug 30, 2023 at 04:01:22PM -0700, Namhyung Kim escreveu: > The read_all_cgroups() is to build a tree of cgroups in the system and > users can look up a cgroup using __cgroup_find(). ⬢[acme@toolbox perf-tools-next]$ alias m='make -k BUILD_BPF_SKEL=1 CORESIGHT=1 O=/tmp/build/perf-tools-next -C tools/perf install-bin && git status && perf test python' ⬢[acme@toolbox perf-tools-next]$ m make: Entering directory '/var/home/acme/git/perf-tools-next/tools/perf' BUILD: Doing 'make -j32' parallel build Warning: Kernel ABI header differences: diff -u tools/include/uapi/linux/perf_event.h include/uapi/linux/perf_event.h diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h diff -u tools/arch/arm64/include/uapi/asm/perf_regs.h arch/arm64/include/uapi/asm/perf_regs.h INSTALL libsubcmd_headers INSTALL libperf_headers INSTALL libapi_headers INSTALL libsymbol_headers INSTALL libbpf_headers CC /tmp/build/perf-tools-next/builtin-lock.o CC /tmp/build/perf-tools-next/util/bpf_lock_contention.o builtin-lock.c: In function ‘__cmd_contention’: builtin-lock.c:2162:9: error: too few arguments to function ‘lock_contention_finish’ 2162 | lock_contention_finish(); | ^~~~~~~~~~~~~~~~~~~~~~ In file included from builtin-lock.c:14: util/lock-contention.h:156:5: note: declared here 156 | int lock_contention_finish(struct lock_contention *con); | ^~~~~~~~~~~~~~~~~~~~~~ make[3]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:97: /tmp/build/perf-tools-next/builtin-lock.o] Error 1 make[3]: *** Waiting for unfinished jobs.... util/bpf_lock_contention.c: In function ‘lock_contention_get_name’: util/bpf_lock_contention.c:231:34: error: ‘struct contention_key’ has no member named ‘lock_addr_or_cgroup’ 231 | u64 cgrp_id = key->lock_addr_or_cgroup; | ^~ make[4]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:97: /tmp/build/perf-tools-next/util/bpf_lock_contention.o] Error 1 make[3]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:150: util] Error 2 make[2]: *** [Makefile.perf:662: /tmp/build/perf-tools-next/perf-in.o] Error 2 make[1]: *** [Makefile.perf:238: sub-make] Error 2 make: *** [Makefile:113: install-bin] Error 2 make: Leaving directory '/var/home/acme/git/perf-tools-next/tools/perf' ⬢[acme@toolbox perf-tools-next]$ Trying to figure this out. - Arnaldo > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > --- > tools/perf/util/cgroup.c | 61 ++++++++++++++++++++++++++++++++++------ > tools/perf/util/cgroup.h | 4 +++ > 2 files changed, 57 insertions(+), 8 deletions(-) > > diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c > index bfb13306d82c..2e969d1464f4 100644 > --- a/tools/perf/util/cgroup.c > +++ b/tools/perf/util/cgroup.c > @@ -48,28 +48,36 @@ static int open_cgroup(const char *name) > } > > #ifdef HAVE_FILE_HANDLE > -int read_cgroup_id(struct cgroup *cgrp) > +static u64 __read_cgroup_id(const char *path) > { > - char path[PATH_MAX + 1]; > - char mnt[PATH_MAX + 1]; > struct { > struct file_handle fh; > uint64_t cgroup_id; > } handle; > int mount_id; > > + handle.fh.handle_bytes = sizeof(handle.cgroup_id); > + if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) > + return -1ULL; > + > + return handle.cgroup_id; > +} > + > +int read_cgroup_id(struct cgroup *cgrp) > +{ > + char path[PATH_MAX + 1]; > + char mnt[PATH_MAX + 1]; > + > if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event")) > return -1; > > scnprintf(path, PATH_MAX, "%s/%s", mnt, cgrp->name); > > - handle.fh.handle_bytes = sizeof(handle.cgroup_id); > - if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) > - return -1; > - > - cgrp->id = handle.cgroup_id; > + cgrp->id = __read_cgroup_id(path); > return 0; > } > +#else > +static inline u64 __read_cgroup_id(const char *path) { return -1ULL; } > #endif /* HAVE_FILE_HANDLE */ > > #ifndef CGROUP2_SUPER_MAGIC > @@ -562,6 +570,11 @@ struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id, > return cgrp; > } > > +struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id) > +{ > + return __cgroup__findnew(root, id, /*create=*/false, /*path=*/NULL); > +} > + > struct cgroup *cgroup__find(struct perf_env *env, uint64_t id) > { > struct cgroup *cgrp; > @@ -587,3 +600,35 @@ void perf_env__purge_cgroups(struct perf_env *env) > } > up_write(&env->cgroups.lock); > } > + > +void read_all_cgroups(struct rb_root *root) > +{ > + char mnt[PATH_MAX]; > + struct cgroup_name *cn; > + int prefix_len; > + > + if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event")) > + return; > + > + /* cgroup_name will have a full path, skip the root directory */ > + prefix_len = strlen(mnt); > + > + /* collect all cgroups in the cgroup_list */ > + if (nftw(mnt, add_cgroup_name, 20, 0) < 0) > + return; > + > + list_for_each_entry(cn, &cgroup_list, list) { > + const char *name; > + u64 cgrp_id; > + > + /* cgroup_name might have a full path, skip the prefix */ > + name = cn->name + prefix_len; > + if (name[0] == '\0') > + name = "/"; > + > + cgrp_id = __read_cgroup_id(cn->name); > + __cgroup__findnew(root, cgrp_id, /*create=*/true, name); > + } > + > + release_cgroup_list(); > +} > diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h > index 12256b78608c..beb6fe1012ed 100644 > --- a/tools/perf/util/cgroup.h > +++ b/tools/perf/util/cgroup.h > @@ -37,6 +37,7 @@ int parse_cgroups(const struct option *opt, const char *str, int unset); > struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id, > const char *path); > struct cgroup *cgroup__find(struct perf_env *env, uint64_t id); > +struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id); > > void perf_env__purge_cgroups(struct perf_env *env); > > @@ -49,6 +50,9 @@ static inline int read_cgroup_id(struct cgroup *cgrp __maybe_unused) > } > #endif /* HAVE_FILE_HANDLE */ > > +/* read all cgroups in the system and save them in the rbtree */ > +void read_all_cgroups(struct rb_root *root); > + > int cgroup_is_v2(const char *subsys); > > #endif /* __CGROUP_H__ */ > -- > 2.42.0.283.g2d96d420d3-goog >
Em Wed, Sep 06, 2023 at 12:38:17PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Wed, Aug 30, 2023 at 04:01:22PM -0700, Namhyung Kim escreveu: > > The read_all_cgroups() is to build a tree of cgroups in the system and > > users can look up a cgroup using __cgroup_find(). > > ⬢[acme@toolbox perf-tools-next]$ alias m='make -k BUILD_BPF_SKEL=1 CORESIGHT=1 O=/tmp/build/perf-tools-next -C tools/perf install-bin && git status && perf test python' > ⬢[acme@toolbox perf-tools-next]$ m > make: Entering directory '/var/home/acme/git/perf-tools-next/tools/perf' > BUILD: Doing 'make -j32' parallel build > Warning: Kernel ABI header differences: > diff -u tools/include/uapi/linux/perf_event.h include/uapi/linux/perf_event.h > diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h > diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h > diff -u tools/arch/arm64/include/uapi/asm/perf_regs.h arch/arm64/include/uapi/asm/perf_regs.h > > INSTALL libsubcmd_headers > INSTALL libperf_headers > INSTALL libapi_headers > INSTALL libsymbol_headers > INSTALL libbpf_headers > CC /tmp/build/perf-tools-next/builtin-lock.o > CC /tmp/build/perf-tools-next/util/bpf_lock_contention.o > builtin-lock.c: In function ‘__cmd_contention’: > builtin-lock.c:2162:9: error: too few arguments to function ‘lock_contention_finish’ > 2162 | lock_contention_finish(); > | ^~~~~~~~~~~~~~~~~~~~~~ > In file included from builtin-lock.c:14: > util/lock-contention.h:156:5: note: declared here > 156 | int lock_contention_finish(struct lock_contention *con); > | ^~~~~~~~~~~~~~~~~~~~~~ > make[3]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:97: /tmp/build/perf-tools-next/builtin-lock.o] Error 1 > make[3]: *** Waiting for unfinished jobs.... > util/bpf_lock_contention.c: In function ‘lock_contention_get_name’: > util/bpf_lock_contention.c:231:34: error: ‘struct contention_key’ has no member named ‘lock_addr_or_cgroup’ > 231 | u64 cgrp_id = key->lock_addr_or_cgroup; > | ^~ > make[4]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:97: /tmp/build/perf-tools-next/util/bpf_lock_contention.o] Error 1 > make[3]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:150: util] Error 2 > make[2]: *** [Makefile.perf:662: /tmp/build/perf-tools-next/perf-in.o] Error 2 > make[1]: *** [Makefile.perf:238: sub-make] Error 2 > make: *** [Makefile:113: install-bin] Error 2 > make: Leaving directory '/var/home/acme/git/perf-tools-next/tools/perf' > ⬢[acme@toolbox perf-tools-next]$ > > Trying to figure this out. So it works on the following patch: ⬢[acme@toolbox perf-tools-next]$ git log --oneline -5 94a54d498ae35c66 (HEAD) perf lock contention: Add -g/--lock-cgroup option defe88978441a00d perf lock contention: Prepare to handle cgroups cc0717270d2f0daa perf cgroup: Add read_all_cgroups() and __cgroup_find() 752d73a1dd62cd4a perf shell completion: Support completion of metrics/metricgroups 72aa5816258bf9fe perf completion: Support completion of libpfm4 events ⬢[acme@toolbox perf-tools-next]$ Please check and submit a v2. - Arnaldo > - Arnaldo > > > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > > --- > > tools/perf/util/cgroup.c | 61 ++++++++++++++++++++++++++++++++++------ > > tools/perf/util/cgroup.h | 4 +++ > > 2 files changed, 57 insertions(+), 8 deletions(-) > > > > diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c > > index bfb13306d82c..2e969d1464f4 100644 > > --- a/tools/perf/util/cgroup.c > > +++ b/tools/perf/util/cgroup.c > > @@ -48,28 +48,36 @@ static int open_cgroup(const char *name) > > } > > > > #ifdef HAVE_FILE_HANDLE > > -int read_cgroup_id(struct cgroup *cgrp) > > +static u64 __read_cgroup_id(const char *path) > > { > > - char path[PATH_MAX + 1]; > > - char mnt[PATH_MAX + 1]; > > struct { > > struct file_handle fh; > > uint64_t cgroup_id; > > } handle; > > int mount_id; > > > > + handle.fh.handle_bytes = sizeof(handle.cgroup_id); > > + if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) > > + return -1ULL; > > + > > + return handle.cgroup_id; > > +} > > + > > +int read_cgroup_id(struct cgroup *cgrp) > > +{ > > + char path[PATH_MAX + 1]; > > + char mnt[PATH_MAX + 1]; > > + > > if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event")) > > return -1; > > > > scnprintf(path, PATH_MAX, "%s/%s", mnt, cgrp->name); > > > > - handle.fh.handle_bytes = sizeof(handle.cgroup_id); > > - if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) > > - return -1; > > - > > - cgrp->id = handle.cgroup_id; > > + cgrp->id = __read_cgroup_id(path); > > return 0; > > } > > +#else > > +static inline u64 __read_cgroup_id(const char *path) { return -1ULL; } > > #endif /* HAVE_FILE_HANDLE */ > > > > #ifndef CGROUP2_SUPER_MAGIC > > @@ -562,6 +570,11 @@ struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id, > > return cgrp; > > } > > > > +struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id) > > +{ > > + return __cgroup__findnew(root, id, /*create=*/false, /*path=*/NULL); > > +} > > + > > struct cgroup *cgroup__find(struct perf_env *env, uint64_t id) > > { > > struct cgroup *cgrp; > > @@ -587,3 +600,35 @@ void perf_env__purge_cgroups(struct perf_env *env) > > } > > up_write(&env->cgroups.lock); > > } > > + > > +void read_all_cgroups(struct rb_root *root) > > +{ > > + char mnt[PATH_MAX]; > > + struct cgroup_name *cn; > > + int prefix_len; > > + > > + if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event")) > > + return; > > + > > + /* cgroup_name will have a full path, skip the root directory */ > > + prefix_len = strlen(mnt); > > + > > + /* collect all cgroups in the cgroup_list */ > > + if (nftw(mnt, add_cgroup_name, 20, 0) < 0) > > + return; > > + > > + list_for_each_entry(cn, &cgroup_list, list) { > > + const char *name; > > + u64 cgrp_id; > > + > > + /* cgroup_name might have a full path, skip the prefix */ > > + name = cn->name + prefix_len; > > + if (name[0] == '\0') > > + name = "/"; > > + > > + cgrp_id = __read_cgroup_id(cn->name); > > + __cgroup__findnew(root, cgrp_id, /*create=*/true, name); > > + } > > + > > + release_cgroup_list(); > > +} > > diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h > > index 12256b78608c..beb6fe1012ed 100644 > > --- a/tools/perf/util/cgroup.h > > +++ b/tools/perf/util/cgroup.h > > @@ -37,6 +37,7 @@ int parse_cgroups(const struct option *opt, const char *str, int unset); > > struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id, > > const char *path); > > struct cgroup *cgroup__find(struct perf_env *env, uint64_t id); > > +struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id); > > > > void perf_env__purge_cgroups(struct perf_env *env); > > > > @@ -49,6 +50,9 @@ static inline int read_cgroup_id(struct cgroup *cgrp __maybe_unused) > > } > > #endif /* HAVE_FILE_HANDLE */ > > > > +/* read all cgroups in the system and save them in the rbtree */ > > +void read_all_cgroups(struct rb_root *root); > > + > > int cgroup_is_v2(const char *subsys); > > > > #endif /* __CGROUP_H__ */ > > -- > > 2.42.0.283.g2d96d420d3-goog > > > > -- > > - Arnaldo
Hi Arnaldo, On Wed, Sep 6, 2023 at 8:41 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > > Em Wed, Sep 06, 2023 at 12:38:17PM -0300, Arnaldo Carvalho de Melo escreveu: > > Em Wed, Aug 30, 2023 at 04:01:22PM -0700, Namhyung Kim escreveu: > > > The read_all_cgroups() is to build a tree of cgroups in the system and > > > users can look up a cgroup using __cgroup_find(). > > > > ⬢[acme@toolbox perf-tools-next]$ alias m='make -k BUILD_BPF_SKEL=1 CORESIGHT=1 O=/tmp/build/perf-tools-next -C tools/perf install-bin && git status && perf test python' > > ⬢[acme@toolbox perf-tools-next]$ m > > make: Entering directory '/var/home/acme/git/perf-tools-next/tools/perf' > > BUILD: Doing 'make -j32' parallel build > > Warning: Kernel ABI header differences: > > diff -u tools/include/uapi/linux/perf_event.h include/uapi/linux/perf_event.h > > diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h > > diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h > > diff -u tools/arch/arm64/include/uapi/asm/perf_regs.h arch/arm64/include/uapi/asm/perf_regs.h > > > > INSTALL libsubcmd_headers > > INSTALL libperf_headers > > INSTALL libapi_headers > > INSTALL libsymbol_headers > > INSTALL libbpf_headers > > CC /tmp/build/perf-tools-next/builtin-lock.o > > CC /tmp/build/perf-tools-next/util/bpf_lock_contention.o > > builtin-lock.c: In function ‘__cmd_contention’: > > builtin-lock.c:2162:9: error: too few arguments to function ‘lock_contention_finish’ > > 2162 | lock_contention_finish(); > > | ^~~~~~~~~~~~~~~~~~~~~~ > > In file included from builtin-lock.c:14: > > util/lock-contention.h:156:5: note: declared here > > 156 | int lock_contention_finish(struct lock_contention *con); > > | ^~~~~~~~~~~~~~~~~~~~~~ > > make[3]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:97: /tmp/build/perf-tools-next/builtin-lock.o] Error 1 > > make[3]: *** Waiting for unfinished jobs.... > > util/bpf_lock_contention.c: In function ‘lock_contention_get_name’: > > util/bpf_lock_contention.c:231:34: error: ‘struct contention_key’ has no member named ‘lock_addr_or_cgroup’ > > 231 | u64 cgrp_id = key->lock_addr_or_cgroup; > > | ^~ > > make[4]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:97: /tmp/build/perf-tools-next/util/bpf_lock_contention.o] Error 1 > > make[3]: *** [/var/home/acme/git/perf-tools-next/tools/build/Makefile.build:150: util] Error 2 > > make[2]: *** [Makefile.perf:662: /tmp/build/perf-tools-next/perf-in.o] Error 2 > > make[1]: *** [Makefile.perf:238: sub-make] Error 2 > > make: *** [Makefile:113: install-bin] Error 2 > > make: Leaving directory '/var/home/acme/git/perf-tools-next/tools/perf' > > ⬢[acme@toolbox perf-tools-next]$ > > > > Trying to figure this out. > > So it works on the following patch: > > ⬢[acme@toolbox perf-tools-next]$ git log --oneline -5 > 94a54d498ae35c66 (HEAD) perf lock contention: Add -g/--lock-cgroup option > defe88978441a00d perf lock contention: Prepare to handle cgroups > cc0717270d2f0daa perf cgroup: Add read_all_cgroups() and __cgroup_find() > 752d73a1dd62cd4a perf shell completion: Support completion of metrics/metricgroups > 72aa5816258bf9fe perf completion: Support completion of libpfm4 events > ⬢[acme@toolbox perf-tools-next]$ > > Please check and submit a v2. Thanks for the report, I'll fix it. Thanks, Namhyung
diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c index bfb13306d82c..2e969d1464f4 100644 --- a/tools/perf/util/cgroup.c +++ b/tools/perf/util/cgroup.c @@ -48,28 +48,36 @@ static int open_cgroup(const char *name) } #ifdef HAVE_FILE_HANDLE -int read_cgroup_id(struct cgroup *cgrp) +static u64 __read_cgroup_id(const char *path) { - char path[PATH_MAX + 1]; - char mnt[PATH_MAX + 1]; struct { struct file_handle fh; uint64_t cgroup_id; } handle; int mount_id; + handle.fh.handle_bytes = sizeof(handle.cgroup_id); + if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) + return -1ULL; + + return handle.cgroup_id; +} + +int read_cgroup_id(struct cgroup *cgrp) +{ + char path[PATH_MAX + 1]; + char mnt[PATH_MAX + 1]; + if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event")) return -1; scnprintf(path, PATH_MAX, "%s/%s", mnt, cgrp->name); - handle.fh.handle_bytes = sizeof(handle.cgroup_id); - if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) - return -1; - - cgrp->id = handle.cgroup_id; + cgrp->id = __read_cgroup_id(path); return 0; } +#else +static inline u64 __read_cgroup_id(const char *path) { return -1ULL; } #endif /* HAVE_FILE_HANDLE */ #ifndef CGROUP2_SUPER_MAGIC @@ -562,6 +570,11 @@ struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id, return cgrp; } +struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id) +{ + return __cgroup__findnew(root, id, /*create=*/false, /*path=*/NULL); +} + struct cgroup *cgroup__find(struct perf_env *env, uint64_t id) { struct cgroup *cgrp; @@ -587,3 +600,35 @@ void perf_env__purge_cgroups(struct perf_env *env) } up_write(&env->cgroups.lock); } + +void read_all_cgroups(struct rb_root *root) +{ + char mnt[PATH_MAX]; + struct cgroup_name *cn; + int prefix_len; + + if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event")) + return; + + /* cgroup_name will have a full path, skip the root directory */ + prefix_len = strlen(mnt); + + /* collect all cgroups in the cgroup_list */ + if (nftw(mnt, add_cgroup_name, 20, 0) < 0) + return; + + list_for_each_entry(cn, &cgroup_list, list) { + const char *name; + u64 cgrp_id; + + /* cgroup_name might have a full path, skip the prefix */ + name = cn->name + prefix_len; + if (name[0] == '\0') + name = "/"; + + cgrp_id = __read_cgroup_id(cn->name); + __cgroup__findnew(root, cgrp_id, /*create=*/true, name); + } + + release_cgroup_list(); +} diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h index 12256b78608c..beb6fe1012ed 100644 --- a/tools/perf/util/cgroup.h +++ b/tools/perf/util/cgroup.h @@ -37,6 +37,7 @@ int parse_cgroups(const struct option *opt, const char *str, int unset); struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id, const char *path); struct cgroup *cgroup__find(struct perf_env *env, uint64_t id); +struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id); void perf_env__purge_cgroups(struct perf_env *env); @@ -49,6 +50,9 @@ static inline int read_cgroup_id(struct cgroup *cgrp __maybe_unused) } #endif /* HAVE_FILE_HANDLE */ +/* read all cgroups in the system and save them in the rbtree */ +void read_all_cgroups(struct rb_root *root); + int cgroup_is_v2(const char *subsys); #endif /* __CGROUP_H__ */
The read_all_cgroups() is to build a tree of cgroups in the system and users can look up a cgroup using __cgroup_find(). Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/perf/util/cgroup.c | 61 ++++++++++++++++++++++++++++++++++------ tools/perf/util/cgroup.h | 4 +++ 2 files changed, 57 insertions(+), 8 deletions(-)