From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DBC8DD3DEAB for ; Fri, 18 Oct 2024 18:46:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6962F6B00A4; Fri, 18 Oct 2024 14:46:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 61E076B00AF; Fri, 18 Oct 2024 14:46:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 496F66B00B1; Fri, 18 Oct 2024 14:46:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 2869E6B00A4 for ; Fri, 18 Oct 2024 14:46:47 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 9D9E21608D1 for ; Fri, 18 Oct 2024 18:46:32 +0000 (UTC) X-FDA: 82687603908.01.A563427 Received: from out-172.mta1.migadu.com (out-172.mta1.migadu.com [95.215.58.172]) by imf11.hostedemail.com (Postfix) with ESMTP id 135E540005 for ; Fri, 18 Oct 2024 18:46:30 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=qDW83nvb; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf11.hostedemail.com: domain of martin.lau@linux.dev designates 95.215.58.172 as permitted sender) smtp.mailfrom=martin.lau@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1729277085; a=rsa-sha256; cv=none; b=6C8Nv+xih8stctL7TZY14Kin0evL8LcSitvxlnXZiqbcux7XZM7FjBEE9IOAhyyjOdQDRm UJMmcAv3hn5+H9U68MiJ4kwy89FtzeLuBaigzIR0JUoibhbixxKlxwxa2EhgVnhGrvBbJs Fx7/hBq7ehlpdgEBHBgUg0JquVL3T1k= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=qDW83nvb; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf11.hostedemail.com: domain of martin.lau@linux.dev designates 95.215.58.172 as permitted sender) smtp.mailfrom=martin.lau@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1729277085; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=+qWqLaFRsovCSA73a8GFikArTFdEXCAPGRK8EgBnsBI=; b=2UDaWFF+3FCQwqbOQMsJf4DWN7uRIlDk9iKkfEcO2CpGnCpUTVlCQlwqPK/HQdHEBFYeXW 4kxvQXo+ACVlARmtdgoo4IiadJnKfpzA4Tl9psZEslHAPCmAZ1/OsjuQKAZqsk/2Ap6XHS OENw0j6b43cs5BDo7tWme/fx1zgVFto= Message-ID: <7b19ad7f-163b-44ed-bc70-f973a7a6f303@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1729277202; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+qWqLaFRsovCSA73a8GFikArTFdEXCAPGRK8EgBnsBI=; b=qDW83nvbu1D1nHDB9IU/Lb4Oq1RVpDDQgbBui4S6YZZh795i4+Og3uj3SyMb+WEFtTzKdq 6DEKsEGo1walFPw61yxeCpWlRQBOqhGwkHE87ESRhNYg8nZmu6FmzFvnD4Psf71Vcer0FU MaTjIHY/Sw8DuOnBmH//5Qy0VJMEcbE= Date: Fri, 18 Oct 2024 11:46:31 -0700 MIME-Version: 1.0 Subject: Re: [PATCH bpf-next 2/2] selftests/bpf: Add a test for open coded kmem_cache iter To: Namhyung Kim Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , 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 References: <20241017080604.541872-1-namhyung@kernel.org> <20241017080604.541872-2-namhyung@kernel.org> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20241017080604.541872-2-namhyung@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 135E540005 X-Stat-Signature: 5yqeaneiuugwgpajspdxukib6ha314an X-Rspam-User: X-HE-Tag: 1729277190-640439 X-HE-Meta: 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 zmNn2i+D E6jTnRsYM4QBAZEc3TokmG8hvfAHAbS471MZ5SmupzkTgPhB1aNC8yQ4cbiNb9t0xKK97DnM8VAgfoK5kX6gj5g7I6x9UkveUqE9AtcjSrBH0ZIIT+WAL6rj1gBV5S4yTOgS5CLWwgVX3ytFS70ReUUbSH0b46CQjoNvPlLLRuvOH3hWH26OCkDE7tHBa/wk+TMfiTysThtzibftpsYtEdgvjx0lTxgQMnHr4lQAy/LhTQxVKS1OcCokOm5pudr9JUNN79aZXBlBRedoLSsuLoXU5J5T6qjylBQxKpwnNwUnQlJ8= 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 10/17/24 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; > + > #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); > + > + /* 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")) with this change. > 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); nit. I think the kmem_cache_iter__destroy() below will also detach, so no need to explicit kmem_cache_iter__detach(). > 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); > + if (r == NULL) > + break; > + > + open_coded_seen++; I am not sure if this will work well if the testing system somehow has another process calling syncfs. It is probably a good idea to guard this by checking the tid of the test_progs at the beginning of this bpf prog. > + > + if (r->obj_size != s->size) > + break; > + } > + return 0; > +}