From: Vlastimil Babka <vbabka@suse.cz>
To: David Hildenbrand <david@redhat.com>,
John Hubbard <jhubbard@nvidia.com>,
Miaohe Lin <linmiaohe@huawei.com>,
akpm@linux-foundation.org
Cc: iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/page_isolation: don't putback unisolated page
Date: Thu, 9 Sep 2021 11:07:25 +0200 [thread overview]
Message-ID: <f9cc811d-2932-845d-da0e-eea493981d11@suse.cz> (raw)
In-Reply-To: <efdab0d6-199a-1bb8-79bf-ea0a5b94c093@redhat.com>
On 9/9/21 10:56, David Hildenbrand wrote:
> On 09.09.21 00:42, John Hubbard wrote:
>> On 9/7/21 2:56 AM, David Hildenbrand wrote:
>> ...
>>>> If this can be handled gracefully, then I'd rather go with VM_WARN_ON.
>>>> Maybe even WARN_ON_ONCE?
>>>>
>>>
>>> I think either VM_BUG_ON() or VM_WARN_ON() -- compiling the runtime
>>> checks out -- should be good
>>> enough.
>>>
>>> I'd just go with VM_BUG_ON(), because anybody messing with
>>> __isolate_free_page() should clearly spot
>>> that we expect the current handling. But no strong opinion.
>>>
>>
>> If in doubt, WARN*() should be preferred over BUG*(). There's a pretty long
>> history of "don't kill the machine unless you have to" emails about this, let
>> me dig up one...OK, maybe not the best example, but the tip of the iceberg:
>
> Please note the subtle difference between BUG_ON and VM_BUG_ON. We expect
> VM_BUG_ON to be compiled out on any production system. So it's really only a
> mean to identify things that really shouldn't be like that during
> debugging/testing.
IIRC Fedora used to have CONFIG_DEBUG_VM enabled, did it change?
> Using WARN... instead of VM_BUG_ON is even worse for production systems.
> There are distros that set panic_on_warn, essentially converting WARN...
> into BUG...
Uh, does any distro really do that?
next prev parent reply other threads:[~2021-09-09 9:07 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-04 9:18 [PATCH] mm/page_isolation: don't putback unisolated page Miaohe Lin
2021-09-06 9:40 ` David Hildenbrand
2021-09-06 11:32 ` Miaohe Lin
2021-09-06 11:50 ` David Hildenbrand
2021-09-06 12:01 ` David Hildenbrand
2021-09-06 12:08 ` Miaohe Lin
2021-09-06 12:02 ` David Hildenbrand
2021-09-06 12:11 ` David Hildenbrand
2021-09-06 12:45 ` Miaohe Lin
2021-09-06 12:49 ` David Hildenbrand
2021-09-07 1:46 ` Miaohe Lin
2021-09-07 9:52 ` David Hildenbrand
2021-09-07 8:08 ` Vlastimil Babka
2021-09-07 9:56 ` David Hildenbrand
2021-09-08 22:42 ` John Hubbard
2021-09-09 8:56 ` David Hildenbrand
2021-09-09 9:07 ` Vlastimil Babka [this message]
2021-09-09 9:37 ` David Hildenbrand
2021-09-09 16:50 ` John Hubbard
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