From patchwork Thu Dec 21 05:00:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13501095 X-Patchwork-Delegate: bpf@iogearbox.net Received: from 66-220-155-178.mail-mxout.facebook.com (66-220-155-178.mail-mxout.facebook.com [66.220.155.178]) (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 343769467 for ; Thu, 21 Dec 2023 05:00:13 +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 55CC82BD13A91; Wed, 20 Dec 2023 21:00:00 -0800 (PST) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau , Hou Tao Subject: [PATCH bpf-next v5 1/8] bpf: Avoid unnecessary extra percpu memory allocation Date: Wed, 20 Dec 2023 21:00:00 -0800 Message-Id: <20231221050000.1970389-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231221045954.1969955-1-yonghong.song@linux.dev> References: <20231221045954.1969955-1-yonghong.song@linux.dev> 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, for percpu memory allocation, say if the user requests allocation size to be 32 bytes, the actually calculated size will be 40 bytes and it further rounds to 64 bytes, and eventually 64 bytes are allocated, wasting 32-byte memory. Change bpf_mem_alloc() to calculate the cache index based on the user-provided allocation size so unnecessary extra memory can be avoided. Suggested-by: Hou Tao Acked-by: Hou Tao Signed-off-by: Yonghong Song --- kernel/bpf/memalloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index aa0fbf000a12..288ec4a967d0 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -833,7 +833,9 @@ void notrace *bpf_mem_alloc(struct bpf_mem_alloc *ma, size_t size) if (!size) return NULL; - idx = bpf_mem_cache_idx(size + LLIST_NODE_SZ); + if (!ma->percpu) + size += LLIST_NODE_SZ; + idx = bpf_mem_cache_idx(size); if (idx < 0) return NULL;