From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org,
catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com,
mhocko@suse.com, david@redhat.com, cai@lca.pw,
logang@deltatee.com, cpandya@codeaurora.org,
arunks@codeaurora.org, dan.j.williams@intel.com,
mgorman@techsingularity.net, osalvador@suse.de,
ard.biesheuvel@arm.com, steve.capper@arm.com, broonie@kernel.org,
valentin.schneider@arm.com, Robin.Murphy@arm.com,
steven.price@arm.com, suzuki.poulose@arm.com,
ira.weiny@intel.com
Subject: Re: [PATCH V8 2/2] arm64/mm: Enable memory hot remove
Date: Tue, 24 Sep 2019 14:11:12 +0530 [thread overview]
Message-ID: <962f7849-f42d-9154-92ae-3125d2f19504@arm.com> (raw)
In-Reply-To: <20190923111745.GG15392@bombadil.infradead.org>
On 09/23/2019 04:47 PM, Matthew Wilcox wrote:
> On Mon, Sep 23, 2019 at 11:13:45AM +0530, Anshuman Khandual wrote:
>> +#ifdef CONFIG_MEMORY_HOTPLUG
>> +static void free_hotplug_page_range(struct page *page, size_t size)
>> +{
>> + WARN_ON(!page || PageReserved(page));
>
> WARN_ON(!page) isn't terribly useful. You're going to crash on the very
> next line when you call page_address() anyway. If this line were
>
> if (WARN_ON(!page || PageReserved(page)))
> return;
>
> it would make sense, or if it were just
>
> WARN_ON(PageReserved(page))
>
> it would also make sense.
I guess WARN_ON(PageReserved(page)) should be good enough to make sure
that page being freed here was originally allocated at runtime for a
previous memory hot add operation and did not some how come from the
memblock reserved area. That was the original objective for this check.
Will change it.
>
>> + free_pages((unsigned long)page_address(page), get_order(size));
>> +}
>
next prev parent reply other threads:[~2019-09-24 8:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-23 5:43 [PATCH V8 0/2] arm64/mm: Enable memory hot remove Anshuman Khandual
2019-09-23 5:43 ` [PATCH V8 1/2] arm64/mm: Hold memory hotplug lock while walking for kernel page table dump Anshuman Khandual
2019-09-23 5:43 ` [PATCH V8 2/2] arm64/mm: Enable memory hot remove Anshuman Khandual
2019-09-23 11:17 ` Matthew Wilcox
2019-09-24 8:41 ` Anshuman Khandual [this message]
2019-09-23 17:39 ` kbuild test robot
2019-10-07 14:17 ` Catalin Marinas
2019-10-08 4:36 ` Anshuman Khandual
2019-10-08 10:55 ` Catalin Marinas
2019-10-08 11:48 ` Anshuman Khandual
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