From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: Martin KaFai Lau <kafai@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Alexei Starovoitov <ast@kernel.org>,
Randy Dunlap <rdunlap@infradead.org>,
Linux-Sparse <linux-sparse@vger.kernel.org>,
Arthur Fabre <afabre@cloudflare.com>
Subject: Re: sparse problem with Linux kernel v5.5
Date: Fri, 7 Feb 2020 11:35:49 +0100 [thread overview]
Message-ID: <20200207103549.lhfxdi6e57v7cvor@ltop.local> (raw)
In-Reply-To: <20200207003434.klmw4vuwbrkv7ykt@kafai-mbp>
On Thu, Feb 06, 2020 at 04:34:34PM -0800, Martin KaFai Lau wrote:
> On Thu, Feb 06, 2020 at 03:47:21PM -0800, Linus Torvalds wrote:
> >
> > Instead, it could just calculate the nbuckets first, and then do the
> > "log2()" on that:
> >
> > /* Use at least 2 buckets, select_bucket() is undefined
> > behavior with 1 bucket */
> > nbuckets = max_t(u32, 2, roundup_pow_of_two(num_possible_cpus()));
> > smap->bucket_log = ilog2(buckets);
> >
> > because honestly, that is just a whole lot more legible anyway. Maybe
> > even split _that_ up, and have the max_t as a separate thing.
> Thanks for the suggestion. I can post a patch for this.
There is also order_base_2() which, I think, does exactly what you
need and shouldn't have the current problem.
-- Luc
next prev parent reply other threads:[~2020-02-07 10:35 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-06 4:49 sparse problem with Linux kernel v5.5 Randy Dunlap
2020-02-06 4:58 ` Randy Dunlap
2020-02-06 7:18 ` Linus Torvalds
2020-02-06 11:46 ` Luc Van Oostenryck
2020-02-06 18:25 ` Randy Dunlap
2020-02-06 20:06 ` Luc Van Oostenryck
2020-02-06 23:47 ` Linus Torvalds
2020-02-07 0:34 ` Martin KaFai Lau
2020-02-07 10:35 ` Luc Van Oostenryck [this message]
2020-02-07 6:34 ` Uwe Kleine-König
2020-02-07 8:29 ` Martin KaFai Lau
2020-02-07 11:34 ` Uwe Kleine-König
2020-02-07 12:43 ` Luc Van Oostenryck
2020-02-07 10:31 ` Luc Van Oostenryck
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