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([2620:10d:c092:500::6:c4f]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488fc1ce408sm259462885e9.14.2026.04.20.04.45.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Apr 2026 04:45:59 -0700 (PDT) Message-ID: Date: Mon, 20 Apr 2026 12:45:58 +0100 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC bpf-next v2 00/18] bpf: Introduce resizable hash map To: Herbert Xu Cc: Alexei Starovoitov , bpf , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin Lau , Kernel Team , Eduard , Kumar Kartikeya Dwivedi , Mykyta Yatsenko References: <20260408-rhash-v2-0-3b3675da1f6e@meta.com> <96b6f76e-1dc9-4d54-9f92-8586796ef607@gmail.com> <4c0e73e1-43c3-48a3-ab89-239fed7e6c23@gmail.com> Content-Language: en-US From: Mykyta Yatsenko In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/18/26 1:43 AM, Herbert Xu wrote: > On Fri, Apr 17, 2026 at 04:16:34PM +0100, Mykyta Yatsenko wrote: >> >> Changing interface is practically not possible - this comes from the bpf >> syscall. >> Linked list solution: we probably can't afford it performance-wise, it's not >> worth it to pay for the linked list maintenance in insert/delete operations, >> to make traversals work well. > > What performance penalty? The linked list is just a pair of pointers. > > Memory-wise it'll be two extra pointers per node. > > Cheers, I'm concerned about pointer chasing, when we inserting a new element to the list or removing existing, we'll need to update pointers of the neighboring elements. It'll be nice to measure it, of course, let me try to prototype it.