From: Qian Cai <cai@lca.pw>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>,
David Hildenbrand <david@redhat.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
pmladek@suse.com, rostedt@goodmis.org, peterz@infradead.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next] mm/hotplug: silence a lockdep splat with printk()
Date: Tue, 14 Jan 2020 20:38:39 -0500 [thread overview]
Message-ID: <8093D190-00C7-43A7-B63E-E06A80D20094@lca.pw> (raw)
In-Reply-To: <20200114171930.9a0dbd9ae82174abf19b3df5@linux-foundation.org>
> On Jan 14, 2020, at 8:19 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Tue, 14 Jan 2020 20:02:31 -0500 Qian Cai <cai@lca.pw> wrote:
>
>>
>>
>>>> @@ -8290,8 +8290,10 @@ bool has_unmovable_pages(struct zone *zo
>>>> return false;
>>>> unmovable:
>>>> WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE);
>>>> - if (flags & REPORT_FAILURE)
>>>> - dump_page(pfn_to_page(pfn + iter), reason);
>>>> + if (flags & REPORT_FAILURE) {
>>>> + page = pfn_to_page(pfn + iter);
>>>
>>> This statement appears to be unnecessary.
>>
>> dump_page() in set_migratetype_isolate() needs that “page”.
>
> local var `page' is never used after this statement.
>
The goal is to reuse the parameter of has_unmovable_pages((…, page, …)
as a return value, so after it returns, dump_page(page, ...) could use it. I
don’t see where it was defined as a local variable.
This is probably a bit too hacky, so I’ll change has_unmovable_pages()
to either return "struct page *” or NULL which is easier to understand.
next prev parent reply other threads:[~2020-01-15 1:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 20:11 [PATCH -next] mm/hotplug: silence a lockdep splat with printk() Qian Cai
2020-01-14 20:20 ` David Hildenbrand
2020-01-14 21:02 ` Michal Hocko
2020-01-14 21:40 ` Qian Cai
2020-01-14 23:53 ` Andrew Morton
2020-01-15 1:02 ` Qian Cai
2020-01-15 1:19 ` Andrew Morton
2020-01-15 1:38 ` Qian Cai [this message]
2020-01-15 8:37 ` Michal Hocko
2020-01-15 9:52 ` Petr Mladek
[not found] ` <D6F57A74-7608-43BE-B909-4350DE95B68C@lca.pw>
2020-01-15 17:02 ` Petr Mladek
2020-01-15 17:16 ` Qian Cai
2020-01-16 14:29 ` Petr Mladek
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