From patchwork Sat Dec 16 02:30:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13495332 Received: from 69-171-232-180.mail-mxout.facebook.com (69-171-232-180.mail-mxout.facebook.com [69.171.232.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D8EF20E2 for ; Sat, 16 Dec 2023 02:30:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id EE0AD2B95839D; Fri, 15 Dec 2023 18:30:04 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau Subject: [PATCH bpf-next v3 0/6] bpf: Reduce memory usage for bpf_global_percpu_ma Date: Fri, 15 Dec 2023 18:30:04 -0800 Message-Id: <20231216023004.3738749-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Currently when a bpf program intends to allocate memory for percpu kptr, the verifier will call bpf_mem_alloc_init() to prefill all supported unit sizes and this caused memory consumption very big for large number of cpus. For example, for 128-cpu system, the total memory consumption with initial prefill is ~175MB. Things will become worse for systems with even more cpus. Patch 1 avoids unnecessary extra percpu memory allocation. Patch 2 addresses memory consumption issue by avoiding to prefill with all unit sizes, i.e. only prefilling with user specified size. Patch 3 further reduces memory consumption by limiting the number of prefill entries for percpu memory allocation. Patch 4 rejects percpu memory allocation with bpf_global_percpu_ma when allocation size is greater than 512 bytes. Patch 5 fixed test_bpf_ma test due to Patch 5. Patch 6 added one test to show the verification failure log message. Changelogs: v2 -> v3: . Clear the bpf_mem_cache if prefill fails. . Change test_bpf_ma percpu allocation tests to use bucket_size as allocation size instead of bucket_size - 8. . Remove __GFP_ZERO flag from __alloc_percpu_gfp() call. v1 -> v2: . Avoid unnecessary extra percpu memory allocation. . Add a separate function to do bpf_global_percpu_ma initialization . promote. . Promote function static 'sizes' array to file static. . Add comments to explain to refill only one item for percpu alloc. Yonghong Song (6): bpf: Avoid unnecessary extra percpu memory allocation bpf: Allow per unit prefill for non-fix-size percpu memory allocator bpf: Refill only one percpu element in memalloc bpf: Limit up to 512 bytes for bpf_global_percpu_ma allocation selftests/bpf: Cope with 512 bytes limit with bpf_global_percpu_ma selftests/bpf: Add a selftest with > 512-byte percpu allocation size include/linux/bpf.h | 2 +- include/linux/bpf_mem_alloc.h | 7 ++ kernel/bpf/core.c | 8 +- kernel/bpf/memalloc.c | 84 +++++++++++++++++-- kernel/bpf/verifier.c | 36 ++++---- .../selftests/bpf/prog_tests/test_bpf_ma.c | 20 +++-- .../selftests/bpf/progs/percpu_alloc_fail.c | 18 ++++ .../testing/selftests/bpf/progs/test_bpf_ma.c | 34 ++++---- 8 files changed, 158 insertions(+), 51 deletions(-)