netdev - Re: [PATCH bpf] bpf: Improve bucket

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Message-ID: <87b3934a-094f-28c1-c5ce-3792c1fa0356@iogearbox.net>
Date:   Fri, 7 Feb 2020 23:04:50 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Martin KaFai Lau <kafai@...com>, bpf@...r.kernel.org
Cc:     Alexei Starovoitov <ast@...nel.org>,
        David Miller <davem@...emloft.net>, kernel-team@...com,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Linux-Sparse <linux-sparse@...r.kernel.org>,
        Luc Van Oostenryck <luc.vanoostenryck@...il.com>,
        netdev@...r.kernel.org, Randy Dunlap <rdunlap@...radead.org>
Subject: Re: [PATCH bpf] bpf: Improve bucket_log calculation logic

On 2/7/20 9:18 AM, Martin KaFai Lau wrote:
> It was reported that the max_t, ilog2, and roundup_pow_of_two macros have
> exponential effects on the number of states in the sparse checker.
> 
> This patch breaks them up by calculating the "nbuckets" first so
> that the "bucket_log" only needs to take ilog2().
> 
> Fixes: 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage")
> Reported-by: Randy Dunlap <rdunlap@...radead.org>
> Reported-by: Luc Van Oostenryck <luc.vanoostenryck@...il.com>
> Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
> Signed-off-by: Martin KaFai Lau <kafai@...com>

Applied (& improved changelog to clarify it's not just sparse), thanks!