Message-ID: <f5964806-992c-d8e1-45f0-2181ee10a83f@oracle.com>
Date:   Wed, 24 Nov 2021 10:46:44 -0800
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Subject: Re: [PATCH 1/3] mm: migrate: Fix the return value of migrate_pages()
Content-Language: en-US
To:     Baolin Wang <baolin.wang@linux.alibaba.com>,
        akpm@linux-foundation.org
Cc:     ziy@nvidia.com, shy828301@gmail.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
References: <cover.1636275127.git.baolin.wang@linux.alibaba.com>
 <6486fabc3e8c66ff613e150af25e89b3147977a6.1636275127.git.baolin.wang@linux.alibaba.com>
 <13b2c5d1-ef3b-3e29-32fe-cb4294bb1531@oracle.com>
 <76c241cc-5de7-d083-312c-373645ee8a77@linux.alibaba.com>
From:   Mike Kravetz <mike.kravetz@oracle.com>
In-Reply-To: <76c241cc-5de7-d083-312c-373645ee8a77@linux.alibaba.com>
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On 11/24/21 02:30, Baolin Wang wrote:
> 
> 
> On 2021/11/24 2:46, Mike Kravetz wrote:
>> On 11/7/21 01:57, Baolin Wang wrote:
>>> @@ -1511,18 +1517,20 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
>>>               case -ENOSYS:
>>>                   /* THP migration is unsupported */
>>>                   if (is_thp) {
>>> -                    if (!try_split_thp(page, &page2, from)) {
>>> +                    nr_thp_failed++;
>>> +                    if (!try_split_thp(page, &page2, &thp_split_pages)) {
>>
>> Does thp_split_pages need to be initialized before this call?
> 
> The declaration "LIST_HEAD(thp_split_pages);" already did list initialization, right?

Correct.  My bad!  I keep forgetting,

#define LIST_HEAD(name) \
        struct list_head name = LIST_HEAD_INIT(name)

-- 
Mike Kravetz