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b=bxHuqttQD+0xXtmQwnrUKYLPQHGvl9DkI5AmwkVKEcDU9ztjL1QYLnw3o4s1PMmHn ODNiT11Ld1g7LYJHDsk9ifabgVS4+TX8kTAfauGFvrkGFeOdjrkV/KGGVf0uzMi6dI VVdYQUGJkKNVtbVDYkzah4nnqYqOc6qg19ST0LzVIJNee8SBnfpK4E0Knkmrl+lhWX S7QpHwCqMAOzcXvF6YcgG7O9j4Qp+lzdWqqfH0agPnDi/vdIQrneEjVS3YbXhx5DWs s6SksGa4rTNGu00+5pEdKrLW7Hc8wN+pCMqeFqf2KnqqvJ+yVBh1E8BofOzDJ8QcZf TmUtFrJcTwlvw== Date: Tue, 22 Oct 2024 10:52:32 -0700 From: Namhyung Kim To: Andrii Nakryiko Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , LKML , bpf@vger.kernel.org, Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, Arnaldo Carvalho de Melo , Kees Cook Subject: Re: [PATCH bpf-next 2/2] selftests/bpf: Add a test for open coded kmem_cache iter Message-ID: References: <20241017080604.541872-1-namhyung@kernel.org> <20241017080604.541872-2-namhyung@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Stat-Signature: tqxhedi9dueyq871xdap8bhojn9i1tgo X-Rspamd-Queue-Id: 15F444001B X-Rspamd-Server: rspam11 X-HE-Tag: 1729619542-208864 X-HE-Meta: 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 4+ijSg0+ K6M3oP395cSU4NAgZYri6HRqfX76G72ZkpAfIx9r3wWcIr/PSoT1/OsVlq2A76GJkf2Fl34phr17FP/WIPNypD+xy1X1Y2z7IfxDKjgJPt6Ip8vxaOYBRqF+B7kvSn55dGUKzziiCDcbfM8ccORjBey+HJamTqLcgW0fC7lkhZ2WxkCGtKE4wmPce0yEM9g1b9bJjRXZCSYXTSQKm+X1dYBHCfFGJGo+T4FB313TB5MeeH/5fZR7OcQh6znV30HXv8msDEq8mnmml5nel7a8ackxgV58IRU86J8gjVVm80JsJCu1y9V6GI25nkKNBmbI12BBrkIH7yIEzU1nOpr4pY/15GuMt0uhfU51IRtTh4A73qxjIWC/Vv+raW1HmfUEkCietl9aiL4rW6HwJiO2pYl+w9K3g4JKPKHZn X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Oct 21, 2024 at 04:36:49PM -0700, Andrii Nakryiko wrote: > On Thu, Oct 17, 2024 at 1:06 AM Namhyung Kim wrote: > > > > The new subtest is attached to sleepable fentry of syncfs() syscall. > > It iterates the kmem_cache using bpf_for_each loop and count the number > > of entries. Finally it checks it with the number of entries from the > > regular iterator. > > > > $ ./vmtest.sh -- ./test_progs -t kmem_cache_iter > > ... > > #130/1 kmem_cache_iter/check_task_struct:OK > > #130/2 kmem_cache_iter/check_slabinfo:OK > > #130/3 kmem_cache_iter/open_coded_iter:OK > > #130 kmem_cache_iter:OK > > Summary: 1/3 PASSED, 0 SKIPPED, 0 FAILED > > > > Also simplify the code by using attach routine of the skeleton. > > > > Signed-off-by: Namhyung Kim > > --- > > .../testing/selftests/bpf/bpf_experimental.h | 6 ++++ > > .../bpf/prog_tests/kmem_cache_iter.c | 28 +++++++++++-------- > > .../selftests/bpf/progs/kmem_cache_iter.c | 24 ++++++++++++++++ > > 3 files changed, 46 insertions(+), 12 deletions(-) > > > > diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h > > index b0668f29f7b394eb..cd8ecd39c3f3c68d 100644 > > --- a/tools/testing/selftests/bpf/bpf_experimental.h > > +++ b/tools/testing/selftests/bpf/bpf_experimental.h > > @@ -582,4 +582,10 @@ extern int bpf_wq_set_callback_impl(struct bpf_wq *wq, > > unsigned int flags__k, void *aux__ign) __ksym; > > #define bpf_wq_set_callback(timer, cb, flags) \ > > bpf_wq_set_callback_impl(timer, cb, flags, NULL) > > + > > +struct bpf_iter_kmem_cache; > > +extern int bpf_iter_kmem_cache_new(struct bpf_iter_kmem_cache *it) __weak __ksym; > > +extern struct kmem_cache *bpf_iter_kmem_cache_next(struct bpf_iter_kmem_cache *it) __weak __ksym; > > +extern void bpf_iter_kmem_cache_destroy(struct bpf_iter_kmem_cache *it) __weak __ksym; > > + > > we should be getting this from vmlinux.h nowadays, so this is probably > unnecessary That'd be nice. Will remove. > > > #endif > > diff --git a/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c b/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c > > index 848d8fc9171fae45..a1fd3bc57c0b21bb 100644 > > --- a/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c > > +++ b/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c > > @@ -68,12 +68,18 @@ static void subtest_kmem_cache_iter_check_slabinfo(struct kmem_cache_iter *skel) > > fclose(fp); > > } > > > > +static void subtest_kmem_cache_iter_open_coded(struct kmem_cache_iter *skel) > > +{ > > + /* To trigger the open coded iterator attached to the syscall */ > > + syncfs(0); > > what Martin said, you still need to filter by PID Yep. > > > + > > + /* It should be same as we've seen from the explicit iterator */ > > + ASSERT_EQ(skel->bss->open_coded_seen, skel->bss->kmem_cache_seen, "open_code_seen_eq"); > > +} > > + > > void test_kmem_cache_iter(void) > > { > > - DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); > > struct kmem_cache_iter *skel = NULL; > > - union bpf_iter_link_info linfo = {}; > > - struct bpf_link *link; > > char buf[256]; > > int iter_fd; > > > > @@ -81,16 +87,12 @@ void test_kmem_cache_iter(void) > > if (!ASSERT_OK_PTR(skel, "kmem_cache_iter__open_and_load")) > > return; > > > > - opts.link_info = &linfo; > > - opts.link_info_len = sizeof(linfo); > > - > > - link = bpf_program__attach_iter(skel->progs.slab_info_collector, &opts); > > - if (!ASSERT_OK_PTR(link, "attach_iter")) > > + if (!ASSERT_OK(kmem_cache_iter__attach(skel), "skel_attach")) > > goto destroy; > > > > - iter_fd = bpf_iter_create(bpf_link__fd(link)); > > + iter_fd = bpf_iter_create(bpf_link__fd(skel->links.slab_info_collector)); > > if (!ASSERT_GE(iter_fd, 0, "iter_create")) > > - goto free_link; > > + goto detach; > > > > memset(buf, 0, sizeof(buf)); > > while (read(iter_fd, buf, sizeof(buf) > 0)) { > > @@ -105,11 +107,13 @@ void test_kmem_cache_iter(void) > > subtest_kmem_cache_iter_check_task_struct(skel); > > if (test__start_subtest("check_slabinfo")) > > subtest_kmem_cache_iter_check_slabinfo(skel); > > + if (test__start_subtest("open_coded_iter")) > > + subtest_kmem_cache_iter_open_coded(skel); > > > > close(iter_fd); > > > > -free_link: > > - bpf_link__destroy(link); > > +detach: > > + kmem_cache_iter__detach(skel); > > destroy: > > kmem_cache_iter__destroy(skel); > > } > > diff --git a/tools/testing/selftests/bpf/progs/kmem_cache_iter.c b/tools/testing/selftests/bpf/progs/kmem_cache_iter.c > > index 72c9dafecd98406b..4c44aa279a5328fe 100644 > > --- a/tools/testing/selftests/bpf/progs/kmem_cache_iter.c > > +++ b/tools/testing/selftests/bpf/progs/kmem_cache_iter.c > > @@ -2,6 +2,8 @@ > > /* Copyright (c) 2024 Google */ > > > > #include "bpf_iter.h" > > +#include "bpf_experimental.h" > > +#include "bpf_misc.h" > > #include > > #include > > > > @@ -33,6 +35,7 @@ extern struct kmem_cache *bpf_get_kmem_cache(u64 addr) __ksym; > > /* Result, will be checked by userspace */ > > int task_struct_found; > > int kmem_cache_seen; > > +int open_coded_seen; > > > > SEC("iter/kmem_cache") > > int slab_info_collector(struct bpf_iter__kmem_cache *ctx) > > @@ -85,3 +88,24 @@ int BPF_PROG(check_task_struct) > > task_struct_found = -2; > > return 0; > > } > > + > > +SEC("fentry.s/" SYS_PREFIX "sys_syncfs") > > +int open_coded_iter(const void *ctx) > > +{ > > + struct kmem_cache *s; > > + > > + bpf_for_each(kmem_cache, s) { > > + struct kmem_cache_result *r; > > + int idx = open_coded_seen; > > + > > + r = bpf_map_lookup_elem(&slab_result, &idx); > > nit: you don't need idx, just `&open_coded_seen` should be fine, I think Ok. > > > + if (r == NULL) > > nit: !r Will change! Thanks, Namhyung > > > + break; > > + > > + open_coded_seen++; > > + > > + if (r->obj_size != s->size) > > + break; > > + } > > + return 0; > > +} > > -- > > 2.47.0.rc1.288.g06298d1525-goog > >