From: Miaohe Lin <linmiaohe@huawei.com>
To: Mike Kravetz <mike.kravetz@oracle.com>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>
Cc: Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@suse.com>,
Shakeel Butt <shakeelb@google.com>,
Oscar Salvador <osalvador@suse.de>,
David Hildenbrand <david@redhat.com>,
Muchun Song <songmuchun@bytedance.com>,
David Rientjes <rientjes@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
HORIGUCHI NAOYA <naoya.horiguchi@nec.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Waiman Long <longman@redhat.com>, Peter Xu <peterx@redhat.com>,
Mina Almasry <almasrymina@google.com>,
"Hillf Danton" <hdanton@sina.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 4/8] hugetlb: create remove_hugetlb_page() to separate functionality
Date: Sat, 27 Mar 2021 09:40:39 +0800 [thread overview]
Message-ID: <8395881b-5c16-d747-aa6e-fd13b7f7f53e@huawei.com> (raw)
In-Reply-To: <def1f500-ae75-5669-5a3d-0472865d2d4c@oracle.com>
On 2021/3/27 3:57, Mike Kravetz wrote:
> On 3/25/21 7:10 PM, Miaohe Lin wrote:
>> On 2021/3/25 8:28, Mike Kravetz wrote:
>>> The new remove_hugetlb_page() routine is designed to remove a hugetlb
>>> page from hugetlbfs processing. It will remove the page from the active
>>> or free list, update global counters and set the compound page
>>> destructor to NULL so that PageHuge() will return false for the 'page'.
>>> After this call, the 'page' can be treated as a normal compound page or
>>> a collection of base size pages.
>>>
>>> remove_hugetlb_page is to be called with the hugetlb_lock held.
>>>
>>> Creating this routine and separating functionality is in preparation for
>>> restructuring code to reduce lock hold times.
>>>
>>> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
>>> ---
>>> mm/hugetlb.c | 70 +++++++++++++++++++++++++++++++++-------------------
>>> 1 file changed, 45 insertions(+), 25 deletions(-)
>>>
>>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>>> index 404b0b1c5258..3938ec086b5c 100644
>>> --- a/mm/hugetlb.c
>>> +++ b/mm/hugetlb.c
>>> @@ -1327,6 +1327,46 @@ static inline void destroy_compound_gigantic_page(struct page *page,
>>> unsigned int order) { }
>>> #endif
>>>
>>> +/*
>>> + * Remove hugetlb page from lists, and update dtor so that page appears
>>> + * as just a compound page. A reference is held on the page.
>>> + * NOTE: hugetlb specific page flags stored in page->private are not
>>> + * automatically cleared. These flags may be used in routines
>>> + * which operate on the resulting compound page.
>>
>> It seems HPageFreed and HPageTemporary is cleared. Which hugetlb specific page flags
>> is reserverd here and why? Could you please give a simple example to clarify
>> this in the comment to help understand this NOTE?
>>
>
> I will remove that NOTE: in the comment to avoid any confusion.
>
> The NOTE was add in the RFC that contained a separate patch to add a flag
> that tracked huge pages allocated from CMA. That flag needed to remain
> for subsequent freeing of such pages. This is no longer needed.
>
Many thanks for explaination. I was confused about that NOTE. :)
>> The code looks good to me. Many thanks!
>> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
>
> Thanks,
>
next prev parent reply other threads:[~2021-03-27 1:40 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 0:28 [PATCH 0/8] make hugetlb put_page safe for all calling contexts Mike Kravetz
2021-03-25 0:28 ` [PATCH 1/8] mm: cma: introduce cma_release_nowait() Mike Kravetz
2021-03-25 9:39 ` Oscar Salvador
2021-03-25 9:45 ` Michal Hocko
2021-03-25 9:54 ` Oscar Salvador
2021-03-25 10:10 ` Michal Hocko
2021-03-25 10:11 ` Michal Hocko
2021-03-25 10:13 ` David Hildenbrand
2021-03-25 10:17 ` Oscar Salvador
2021-03-25 10:24 ` Michal Hocko
2021-03-25 9:56 ` David Hildenbrand
2021-03-25 10:22 ` Michal Hocko
2021-03-25 16:56 ` Mike Kravetz
2021-03-25 17:15 ` David Hildenbrand
2021-03-25 20:12 ` Minchan Kim
2021-03-25 23:19 ` Roman Gushchin
2021-03-25 23:49 ` Mike Kravetz
2021-03-26 21:32 ` Mike Kravetz
2021-03-29 7:46 ` Michal Hocko
2021-03-29 22:27 ` Mike Kravetz
2021-03-25 0:28 ` [PATCH 2/8] mm: hugetlb: don't drop hugetlb_lock around cma_release() call Mike Kravetz
2021-03-25 0:28 ` [PATCH 3/8] hugetlb: add per-hstate mutex to synchronize user adjustments Mike Kravetz
2021-03-25 10:47 ` Michal Hocko
2021-03-25 12:29 ` Oscar Salvador
2021-03-26 1:52 ` Miaohe Lin
2021-03-25 0:28 ` [PATCH 4/8] hugetlb: create remove_hugetlb_page() to separate functionality Mike Kravetz
2021-03-25 10:49 ` Michal Hocko
2021-03-26 2:10 ` Miaohe Lin
2021-03-26 19:57 ` Mike Kravetz
2021-03-27 1:40 ` Miaohe Lin [this message]
2021-03-27 6:36 ` [External] " Muchun Song
2021-03-25 0:28 ` [PATCH 5/8] hugetlb: call update_and_free_page without hugetlb_lock Mike Kravetz
2021-03-25 10:55 ` Michal Hocko
2021-03-25 17:12 ` Mike Kravetz
2021-03-25 19:39 ` Michal Hocko
2021-03-25 20:33 ` Mike Kravetz
2021-03-27 6:54 ` [External] " Muchun Song
2021-03-28 21:40 ` Mike Kravetz
2021-03-25 0:28 ` [PATCH 6/8] hugetlb: change free_pool_huge_page to remove_pool_huge_page Mike Kravetz
2021-03-25 11:06 ` Michal Hocko
2021-03-25 17:29 ` Mike Kravetz
2021-03-25 0:28 ` [PATCH 7/8] hugetlb: make free_huge_page irq safe Mike Kravetz
2021-03-25 11:21 ` Michal Hocko
2021-03-25 17:32 ` Mike Kravetz
2021-03-27 7:06 ` [External] " Muchun Song
2021-03-29 7:49 ` Michal Hocko
2021-03-29 22:44 ` Mike Kravetz
2021-03-25 0:28 ` [PATCH 8/8] hugetlb: add lockdep_assert_held() calls for hugetlb_lock Mike Kravetz
2021-03-25 11:22 ` Michal Hocko
2021-03-26 2:12 ` Miaohe Lin
2021-03-27 8:14 ` [External] " Muchun Song
2021-03-26 1:42 ` [PATCH 0/8] make hugetlb put_page safe for all calling contexts Miaohe Lin
2021-03-26 20:00 ` Mike Kravetz
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