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From: Jani Nikula <jani.nikula@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>,
	John Hubbard <jhubbard@nvidia.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-doc@vger.kernel.org, kexec@lists.infradead.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	David Laight <David.Laight@aculab.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Andy Whitcroft <apw@canonical.com>, Joe Perches <joe@perches.com>,
	Dwaipayan Ray <dwaipayanray1@gmail.com>,
	Lukas Bulwahn <lukas.bulwahn@gmail.com>,
	Baoquan He <bhe@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
	Stephen Johnston <sjohnsto@redhat.com>,
	Prarit Bhargava <prarit@redhat.com>
Subject: Re: [PATCH RFC 1/2] coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel")
Date: Mon, 29 Aug 2022 12:25:02 +0300	[thread overview]
Message-ID: <87tu5vflld.fsf@intel.com> (raw)
In-Reply-To: <CAHk-=wit-DmhMfQErY29JSPjFgebx_Ld+pnerc4J2Ag990WwAA@mail.gmail.com>

On Sun, 28 Aug 2022, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> So WARN_ON_ONCE() is the thing to aim for. BUG_ON() is the thing for
> "oops, I really don't know what to do, and I physically *cannot*
> continue" (and that is *not* "I'm too lazy to do error handling").

Any insight for the tradeoff between WARN_ON_ONCE() and WARN_ON(),
i.e. wasting the static once variable per use site vs. littering the
dmesg on every hit? I see there have been some improvements with the
__WARN_FLAGS() stuff, but is the data use really neglible?

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center

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WARNING: multiple messages have this Message-ID (diff)
From: Jani Nikula <jani.nikula@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>,
	John Hubbard <jhubbard@nvidia.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-doc@vger.kernel.org, kexec@lists.infradead.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	David Laight <David.Laight@aculab.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Andy Whitcroft <apw@canonical.com>, Joe Perches <joe@perches.com>,
	Dwaipayan Ray <dwaipayanray1@gmail.com>,
	Lukas Bulwahn <lukas.bulwahn@gmail.com>,
	Baoquan He <bhe@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
	Stephen Johnston <sjohnsto@redhat.com>,
	Prarit Bhargava <prarit@redhat.com>
Subject: Re: [PATCH RFC 1/2] coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel")
Date: Mon, 29 Aug 2022 12:25:02 +0300	[thread overview]
Message-ID: <87tu5vflld.fsf@intel.com> (raw)
In-Reply-To: <CAHk-=wit-DmhMfQErY29JSPjFgebx_Ld+pnerc4J2Ag990WwAA@mail.gmail.com>

On Sun, 28 Aug 2022, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> So WARN_ON_ONCE() is the thing to aim for. BUG_ON() is the thing for
> "oops, I really don't know what to do, and I physically *cannot*
> continue" (and that is *not* "I'm too lazy to do error handling").

Any insight for the tradeoff between WARN_ON_ONCE() and WARN_ON(),
i.e. wasting the static once variable per use site vs. littering the
dmesg on every hit? I see there have been some improvements with the
__WARN_FLAGS() stuff, but is the data use really neglible?

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center

  parent reply	other threads:[~2022-08-29  9:25 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-24 16:30 [PATCH RFC 0/2] coding-style.rst: document BUG() and WARN() rules David Hildenbrand
2022-08-24 16:30 ` David Hildenbrand
2022-08-24 16:30 ` [PATCH RFC 1/2] coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel") David Hildenbrand
2022-08-24 16:30   ` David Hildenbrand
2022-08-24 21:59   ` John Hubbard
2022-08-24 21:59     ` John Hubbard
2022-08-25 12:12     ` David Hildenbrand
2022-08-25 12:12       ` David Hildenbrand
2022-08-26  1:43       ` Dave Young
2022-08-26  1:43         ` Dave Young
2022-08-26 17:02         ` David Hildenbrand
2022-08-26 17:02           ` David Hildenbrand
2022-08-29  1:55           ` Dave Young
2022-08-29  1:55             ` Dave Young
2022-08-29  3:07             ` Linus Torvalds
2022-08-29  3:07               ` Linus Torvalds
2022-08-29  4:49               ` John Hubbard
2022-08-29  4:49                 ` John Hubbard
2022-08-29 17:19                 ` Linus Torvalds
2022-08-29 17:19                   ` Linus Torvalds
2022-08-29  8:44               ` David Hildenbrand
2022-08-29  8:44                 ` David Hildenbrand
2022-08-29  9:25               ` Jani Nikula [this message]
2022-08-29  9:25                 ` Jani Nikula
2022-08-24 16:31 ` [PATCH RFC 2/2] checkpatch: warn on usage of VM_BUG_ON() and friends David Hildenbrand
2022-08-24 16:31   ` David Hildenbrand
2022-08-24 16:52   ` Joe Perches
2022-08-24 16:52     ` Joe Perches
2022-08-24 19:00     ` David Hildenbrand
2022-08-24 19:00       ` David Hildenbrand
2022-08-25  9:58     ` David Hildenbrand
2022-08-25  9:58       ` David Hildenbrand
2022-08-25 11:43       ` Jani Nikula
2022-08-25 11:43         ` Jani Nikula
2022-08-25 11:51         ` David Hildenbrand
2022-08-25 11:51           ` David Hildenbrand
2022-08-25  2:30 ` [PATCH RFC 0/2] coding-style.rst: document BUG() and WARN() rules John Hubbard
2022-08-25  2:30   ` John Hubbard

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