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From: Yonghong Song <yonghong.song@linux.dev>
To: Martin KaFai Lau <martin.lau@linux.dev>, bpf@vger.kernel.org
Cc: 'Alexei Starovoitov ' <ast@kernel.org>,
	'Andrii Nakryiko ' <andrii@kernel.org>,
	'Daniel Borkmann ' <daniel@iogearbox.net>,
	netdev@vger.kernel.org, kernel-team@meta.com,
	Aditi Ghag <aditi.ghag@isovalent.com>
Subject: Re: [PATCH v2 bpf 1/3] bpf: iter_udp: Retry with a larger batch size without going back to the previous bucket
Date: Thu, 11 Jan 2024 20:52:19 -0800	[thread overview]
Message-ID: <ca166fda-4474-4046-b098-c39fd5c42def@linux.dev> (raw)
In-Reply-To: <20240110175743.2220907-2-martin.lau@linux.dev>


On 1/10/24 9:57 AM, Martin KaFai Lau wrote:
> From: Martin KaFai Lau <martin.lau@kernel.org>
>
> The current logic is to use a default size 16 to batch the whole bucket.
> If it is too small, it will retry with a larger batch size.
>
> The current code accidentally does a state->bucket-- before retrying.
> This goes back to retry with the previous bucket which has already
> been done. This patch fixed it.
>
> It is hard to create a selftest. I added a WARN_ON(state->bucket < 0),
> forced a particular port to be hashed to the first bucket,
> created >16 sockets, and observed the for-loop went back
> to the "-1" bucket.
>
> Cc: Aditi Ghag <aditi.ghag@isovalent.com>
> Fixes: c96dac8d369f ("bpf: udp: Implement batching for sockets iterator")
> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Acked-by: Yonghong Song <yonghong.song@linux.dev>


  reply	other threads:[~2024-01-12  4:52 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-10 17:57 [PATCH v2 bpf 0/3] bpf: Fix backward progress bug in bpf_iter_udp Martin KaFai Lau
2024-01-10 17:57 ` [PATCH v2 bpf 1/3] bpf: iter_udp: Retry with a larger batch size without going back to the previous bucket Martin KaFai Lau
2024-01-12  4:52   ` Yonghong Song [this message]
2024-01-10 17:57 ` [PATCH v2 bpf 2/3] bpf: Avoid iter->offset making backward progress in bpf_iter_udp Martin KaFai Lau
2024-01-12  5:33   ` Yonghong Song
2024-01-10 17:57 ` [PATCH v2 bpf 3/3] selftests/bpf: Test udp and tcp iter batching Martin KaFai Lau
2024-01-12 17:50   ` Yonghong Song
2024-01-12 18:10     ` Martin KaFai Lau

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