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: Wed, 28 Apr 2021 19:31:50 -0700 [thread overview]
Message-ID: <98f191e8-b509-e541-9d9d-76029c74d241@oracle.com> (raw)
In-Reply-To: <CAMZfGtVbB6YwUMg2ECpdmniQ_vt_3AwdVAuu0GdUJfzWZgQpyg@mail.gmail.com>
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:
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9c617c19fc18..f8e5013a6b46 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2420,14 +2420,15 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
/*
* Before dissolving the page, we need to allocate a new one for the
- * pool to remain stable. Using alloc_buddy_huge_page() allows us to
- * not having to deal with prep_new_huge_page() and avoids dealing of any
- * counters. This simplifies and let us do the whole thing under the
- * lock.
+ * pool to remain stable. Here, we allocate the page and 'prep' it
+ * by doing everything but actually updating counters and adding to
+ * the pool. This simplifies and let us do most of the processing
+ * under the lock.
*/
new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL);
if (!new_page)
return -ENOMEM;
+ __prep_new_huge_page(h, new_page);
retry:
spin_lock_irq(&hugetlb_lock);
@@ -2473,7 +2474,6 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
* Reference count trick is needed because allocator gives us
* referenced page but the pool requires pages with 0 refcount.
*/
- __prep_new_huge_page(h, new_page);
__prep_account_new_huge_page(h, nid);
page_ref_dec(new_page);
enqueue_huge_page(h, new_page);
@@ -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);
return ret;
}
--
Mike Kravetz
next prev parent reply other threads:[~2021-04-29 2:34 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 [this message]
2021-04-29 4:02 ` Muchun Song
2021-04-29 22:23 ` Mike Kravetz
2021-04-29 23:19 ` Mike Kravetz
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