From: Mike Kravetz <mike.kravetz@oracle.com>
To: Muchun Song <songmuchun@bytedance.com>
Cc: "Jonathan Corbet" <corbet@lwn.net>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
bp@alien8.de, "X86 ML" <x86@kernel.org>,
hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org,
"Peter Zijlstra" <peterz@infradead.org>,
"Alexander Viro" <viro@zeniv.linux.org.uk>,
"Andrew Morton" <akpm@linux-foundation.org>,
paulmck@kernel.org, pawan.kumar.gupta@linux.intel.com,
"Randy Dunlap" <rdunlap@infradead.org>,
oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de,
"Mina Almasry" <almasrymina@google.com>,
"David Rientjes" <rientjes@google.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Oscar Salvador" <osalvador@suse.de>,
"Michal Hocko" <mhocko@suse.com>,
"Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>,
"David Hildenbrand" <david@redhat.com>,
"HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>,
"Joao Martins" <joao.m.martins@oracle.com>,
"Xiongchun duan" <duanxiongchun@bytedance.com>,
fam.zheng@bytedance.com, zhengqi.arch@bytedance.com,
linux-doc@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
"Linux Memory Management List" <linux-mm@kvack.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [External] Re: [PATCH v21 0/9] Free some vmemmap pages of HugeTLB page
Date: Thu, 29 Apr 2021 16:19:40 -0700 [thread overview]
Message-ID: <5f363b58-f70a-4a6a-9761-aae93cb49138@oracle.com> (raw)
In-Reply-To: <4489afcd-be3e-7830-4e37-03abe454486a@oracle.com>
On 4/29/21 3:23 PM, Mike Kravetz wrote:
> On 4/28/21 9:02 PM, Muchun Song wrote:
>> On Thu, Apr 29, 2021 at 10:32 AM Mike Kravetz <mike.kravetz@oracle.com> wrote:
>>>
>>> On 4/28/21 5:26 AM, Muchun Song wrote:
>>>> On Wed, Apr 28, 2021 at 7:47 AM Mike Kravetz <mike.kravetz@oracle.com> wrote:
>>>>>
>>>>> Thanks! I will take a look at the modifications soon.
>>>>>
>>>>> I applied the patches to Andrew's mmotm-2021-04-21-23-03, ran some tests and
>>>>> got the following warning. We may need to special case that call to
>>>>> __prep_new_huge_page/free_huge_page_vmemmap from alloc_and_dissolve_huge_page
>>>>> as it is holding hugetlb lock with IRQs disabled.
>>>>
>>>> Good catch. Thanks Mike. I will fix it in the next version. How about this:
>>>>
>>>> @@ -1618,7 +1617,8 @@ static void __prep_new_huge_page(struct hstate
>>>> *h, struct page *page)
>>>>
>>>> static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
>>>> {
>>>> + free_huge_page_vmemmap(h, page);
>>>> __prep_new_huge_page(page);
>>>> spin_lock_irq(&hugetlb_lock);
>>>> __prep_account_new_huge_page(h, nid);
>>>> spin_unlock_irq(&hugetlb_lock);
>>>> @@ -2429,6 +2429,7 @@ static int alloc_and_dissolve_huge_page(struct
>>>> hstate *h, struct page *old_page,
>>>> if (!new_page)
>>>> return -ENOMEM;
>>>>
>>>> + free_huge_page_vmemmap(h, new_page);
>>>> retry:
>>>> spin_lock_irq(&hugetlb_lock);
>>>> if (!PageHuge(old_page)) {
>>>> @@ -2489,7 +2490,7 @@ static int alloc_and_dissolve_huge_page(struct
>>>> hstate *h, struct page *old_page,
>>>>
>>>> free_new:
>>>> spin_unlock_irq(&hugetlb_lock);
>>>> - __free_pages(new_page, huge_page_order(h));
>>>> + update_and_free_page(h, new_page, false);
>>>>
>>>> return ret;
>>>> }
>>>>
>>>>
>>>
>>> Another option would be to leave the prep* routines as is and only
>>> modify alloc_and_dissolve_huge_page as follows:
>>
>> OK. LGTM. I will use this. Thanks Mike.
>
> There are issues with my suggested patch below. I am occasionally
> hitting the BUG that checks for page ref count being zero at put_page
> time. Still do not fully understand, but I do not hit the same BUG
> with your patch above. Please do not use my patch below.
>
Ah! The issue is pretty obvious.
> @@ -2489,7 +2489,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
>
> free_new:
> spin_unlock_irq(&hugetlb_lock);
> - __free_pages(new_page, huge_page_order(h));
> + update_and_free_page(h, old_page, false);
That should of course be:
update_and_free_page(h, new_page, false);
>
> return ret;
> }
>
--
Mike Kravetz
prev parent reply other threads:[~2021-04-29 23:20 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-25 7:07 [PATCH v21 0/9] Free some vmemmap pages of HugeTLB page Muchun Song
2021-04-25 7:07 ` [PATCH v21 1/9] mm: memory_hotplug: factor out bootmem core functions to bootmem_info.c Muchun Song
2021-04-25 7:07 ` [PATCH v21 2/9] mm: hugetlb: introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2021-04-25 7:07 ` [PATCH v21 3/9] mm: hugetlb: gather discrete indexes of tail page Muchun Song
2021-04-25 7:07 ` [PATCH v21 4/9] mm: hugetlb: free the vmemmap pages associated with each HugeTLB page Muchun Song
2021-04-25 7:07 ` [PATCH v21 5/9] mm: hugetlb: defer freeing of HugeTLB pages Muchun Song
2021-04-25 7:07 ` [PATCH v21 6/9] mm: hugetlb: alloc the vmemmap pages associated with each HugeTLB page Muchun Song
2021-04-29 2:42 ` Mike Kravetz
2021-04-29 4:05 ` [External] " Muchun Song
2021-04-25 7:07 ` [PATCH v21 7/9] mm: hugetlb: add a kernel parameter hugetlb_free_vmemmap Muchun Song
2021-04-25 7:07 ` [PATCH v21 8/9] mm: memory_hotplug: disable memmap_on_memory when hugetlb_free_vmemmap enabled Muchun Song
2021-04-25 7:07 ` [PATCH v21 9/9] mm: hugetlb: introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
2021-04-27 23:47 ` [PATCH v21 0/9] Free some vmemmap pages of HugeTLB page Mike Kravetz
2021-04-28 12:26 ` [External] " Muchun Song
2021-04-29 2:31 ` Mike Kravetz
2021-04-29 4:02 ` Muchun Song
2021-04-29 22:23 ` Mike Kravetz
2021-04-29 23:19 ` Mike Kravetz [this message]
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