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From: Christoph Hellwig <hch@infradead.org>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Michal Suchanek <msuchanek@suse.de>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Jiri Olsa <jolsa@kernel.org>, Hritik Vijay <hritikxx8@gmail.com>,
	bpf <bpf@vger.kernel.org>, Linux-Net <netdev@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH] mm/page_alloc: Work around a pahole limitation with zero-sized struct pagesets
Date: Thu, 27 May 2021 09:04:24 +0100	[thread overview]
Message-ID: <YK9SiLX1E1KAZORb@infradead.org> (raw)
In-Reply-To: <20210526080741.GW30378@techsingularity.net>

On Wed, May 26, 2021 at 09:07:41AM +0100, Mel Gorman wrote:
> +    !defined(CONFIG_DEBUG_LOCK_ALLOC) &&		\
> +    !defined(CONFIG_PAHOLE_HAS_ZEROSIZE_PERCPU_SUPPORT)
> +	/*
> +	 * pahole 1.21 and earlier gets confused by zero-sized per-CPU
> +	 * variables and produces invalid BTF. Ensure that
> +	 * sizeof(struct pagesets) != 0 for older versions of pahole.
> +	 */
> +	char __pahole_hack;
> +	#warning "pahole too old to support zero-sized struct pagesets"
> +#endif

Err, hell no.  We should not mess up the kernel for broken tools that
are not relevant to the kernel build itself ever.

  parent reply	other threads:[~2021-05-27  8:05 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-26  8:07 Mel Gorman
2021-05-26  8:16 ` David Hildenbrand
2021-05-26  8:33 ` (BTF) " Michal Suchánek
2021-05-26  9:00   ` Mel Gorman
2021-05-26 17:00   ` Andrii Nakryiko
2021-05-26 17:43     ` Michal Suchánek
2021-05-26 16:57 ` Andrii Nakryiko
2021-05-26 18:13   ` Mel Gorman
2021-05-26 18:41     ` Andrii Nakryiko
2021-05-27  8:04 ` Christoph Hellwig [this message]
2021-05-27  9:04   ` Mel Gorman
2021-05-27  9:18     ` Christoph Hellwig
2021-05-27 14:37       ` Andrii Nakryiko
2021-05-27 14:41         ` Andrii Nakryiko
2021-05-28  8:09           ` David Laight
2021-05-28  9:04             ` Mel Gorman
2021-05-28  9:49               ` David Laight
2021-05-28  9:56                 ` Michal Suchánek
2021-05-28 13:09                   ` David Laight
2021-05-30  0:46             ` Andrii Nakryiko

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