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b=rNRCyCUYFtBOaRu6gW4krYeC+MqSKedWai4cW33aGntkqKOYMOoZnunEQ9Rwcj6c5 eDcq8piHO84drnpqV7u6z+VT37qs8BMx2wv7SIuwFOH8/FexO3aRxYh4U0oILNshap eKknqGpB9pU8hWbhk9rvZD9dcL0q6DmmY3f2pm5WrgNK/XAMqyHHVYKcmgIvJHd783 8/KYgZ0YUa0UtSQT4aBQR7/62WRuSIC6FzFzG/TECTayft6Sy2sHaO8RPpk81WwuX5 jzXbYTzHvnDCRWd/pVLPHTqgoS39pLNBgeuBNPKBZcn2UQyksmRfLJu+BLjsruzoQu 8cFOqfo5w1krw== Date: Wed, 30 Oct 2024 14:35:38 -0700 From: Namhyung Kim To: Alexei Starovoitov 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 , Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm , Arnaldo Carvalho de Melo , Kees Cook Subject: Re: [PATCH v2 bpf-next 2/2] selftests/bpf: Add a test for open coded kmem_cache iter Message-ID: References: <20241024074815.1255066-1-namhyung@kernel.org> <20241024074815.1255066-2-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-Stat-Signature: jqjkiiq375dwehk51d31qbupje7gkg46 X-Rspamd-Queue-Id: DB96D8001B X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1730324091-369283 X-HE-Meta: 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 srEudyx2 R+NyEh7+BVePx2PIx15WIvrZzIFS6Ji7wNZUMcropYHnD+7mSXvx+77NdAGlgii2xdHpFqvHcaWm1EQN0CB+PFDbY8wkE4XXucp/ovKB1jHce3kx8DiwSPx6bY8n6FtSRceogcv5Mnh3ji/H58R0UXXsm+do47LNkeswzjZxXXi6NJFK2VN3VEDT5o7smaDQBuTADVcAaFp/Ea+VEmSZwpwzPIjmX6buGjtjNBFcSGp/gsCrF/VqMe1l0bpH4ujoP4DlFw88QNz2vTg3ViJS1YC6QX//xNmknZHZnOqx5BO1h4/GtggSwYkSfLy54lPTzhIJVlasz8iTSLFqM1N3EujxUI4zJCdUn1Fqlf9JttKg994Qraan6+vE1WeWCM436uqlpzMmIREem9NQDV/SNm8Icc9G4tYEVLzZB 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 Tue, Oct 29, 2024 at 06:40:46PM -0700, Namhyung Kim wrote: > Hello, > > On Thu, Oct 24, 2024 at 11:08:00AM -0700, Alexei Starovoitov wrote: > > On Thu, Oct 24, 2024 at 12:48 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 > > > --- [SNIP] > > > +SEC("fentry.s/" SYS_PREFIX "sys_syncfs") > > > +int open_coded_iter(const void *ctx) > > > +{ > > > + struct kmem_cache *s; > > > + > > > + if (tgid != bpf_get_current_pid_tgid() >> 32) > > > + return 0; > > > > Pls use syscall prog type and prog_run() it. > > No need to attach to exotic syscalls and filter by pid. > > Sure, will update in v3. > > > > > > + > > > + bpf_for_each(kmem_cache, s) { > > > + struct kmem_cache_result *r; > > > + > > > + r = bpf_map_lookup_elem(&slab_result, &open_coded_seen); > > > + if (!r) > > > + break; > > > + > > > + open_coded_seen++; > > > + > > > + if (r->obj_size != s->size) > > > + break; > > > > The order of 'if' and ++ should probably be changed ? > > Otherwise the last object isn't sufficiently checked. > > I don't think so. The last element should be an actual slab cache and > then the iterator will return NULL to break the loop. I don't expect it > will hit the if statement. Oh, it seems you meant checking the obj_size. Ok then, I can move the increment after the check. Thanks, Namhyung