From: Muchun Song <songmuchun@bytedance.com>
To: corbet@lwn.net, mike.kravetz@oracle.com, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com,
dave.hansen@linux.intel.com, luto@kernel.org,
peterz@infradead.org, viro@zeniv.linux.org.uk,
akpm@linux-foundation.org, paulmck@kernel.org,
mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com,
rdunlap@infradead.org, oneukum@suse.com,
anshuman.khandual@arm.com, jroedel@suse.de,
almasrymina@google.com, rientjes@google.com
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Muchun Song <songmuchun@bytedance.com>
Subject: [RFC PATCH 06/24] mm/hugetlb: Introduce pgtable allocation/freeing helpers
Date: Tue, 15 Sep 2020 20:59:29 +0800 [thread overview]
Message-ID: <20200915125947.26204-7-songmuchun@bytedance.com> (raw)
In-Reply-To: <20200915125947.26204-1-songmuchun@bytedance.com>
On some architectures, the vmemmap areas use huge page mapping.
If we want to free the unused vmemmap pages, we have to split
the huge pmd firstly. So we should pre-allocate pgtable to split
huge pmd.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
include/linux/hugetlb.h | 17 ++++++
mm/hugetlb.c | 117 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 134 insertions(+)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index eed3dd3bd626..ace304a6196c 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -593,6 +593,23 @@ static inline unsigned int blocks_per_huge_page(struct hstate *h)
#include <asm/hugetlb.h>
+#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
+#ifndef arch_vmemmap_support_huge_mapping
+static inline bool arch_vmemmap_support_huge_mapping(void)
+{
+ return false;
+}
+#endif
+
+#ifndef VMEMMAP_HPAGE_SHIFT
+#define VMEMMAP_HPAGE_SHIFT PMD_SHIFT
+#endif
+#define VMEMMAP_HPAGE_ORDER (VMEMMAP_HPAGE_SHIFT - PAGE_SHIFT)
+#define VMEMMAP_HPAGE_NR (1 << VMEMMAP_HPAGE_ORDER)
+#define VMEMMAP_HPAGE_SIZE ((1UL) << VMEMMAP_HPAGE_SHIFT)
+#define VMEMMAP_HPAGE_MASK (~(VMEMMAP_HPAGE_SIZE - 1))
+#endif /* CONFIG_HUGETLB_PAGE_FREE_VMEMMAP */
+
#ifndef is_hugepage_only_range
static inline int is_hugepage_only_range(struct mm_struct *mm,
unsigned long addr, unsigned long len)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f1b2b733b49b..d6ae9b6876be 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1295,11 +1295,108 @@ static inline void destroy_compound_gigantic_page(struct page *page,
#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
#define RESERVE_VMEMMAP_NR 2U
+#define page_huge_pte(page) ((page)->pmd_huge_pte)
+
static inline unsigned int nr_free_vmemmap(struct hstate *h)
{
return h->nr_free_vmemmap_pages;
}
+static inline unsigned int nr_vmemmap(struct hstate *h)
+{
+ return nr_free_vmemmap(h) + RESERVE_VMEMMAP_NR;
+}
+
+static inline unsigned long nr_vmemmap_size(struct hstate *h)
+{
+ return (unsigned long)nr_vmemmap(h) << PAGE_SHIFT;
+}
+
+static inline unsigned int nr_pgtable(struct hstate *h)
+{
+ unsigned long vmemmap_size = nr_vmemmap_size(h);
+
+ if (!arch_vmemmap_support_huge_mapping())
+ return 0;
+
+ /*
+ * No need pre-allocate page tabels when there is no vmemmap pages
+ * to free.
+ */
+ if (!nr_free_vmemmap(h))
+ return 0;
+
+ return ALIGN(vmemmap_size, VMEMMAP_HPAGE_SIZE) >> VMEMMAP_HPAGE_SHIFT;
+}
+
+static inline void vmemmap_pgtable_init(struct page *page)
+{
+ page_huge_pte(page) = NULL;
+}
+
+static void vmemmap_pgtable_deposit(struct page *page, pte_t *pte_p)
+{
+ pgtable_t pgtable = virt_to_page(pte_p);
+
+ /* FIFO */
+ if (!page_huge_pte(page))
+ INIT_LIST_HEAD(&pgtable->lru);
+ else
+ list_add(&pgtable->lru, &page_huge_pte(page)->lru);
+ page_huge_pte(page) = pgtable;
+}
+
+static pte_t *vmemmap_pgtable_withdraw(struct page *page)
+{
+ pgtable_t pgtable;
+
+ /* FIFO */
+ pgtable = page_huge_pte(page);
+ if (unlikely(!pgtable))
+ return NULL;
+ page_huge_pte(page) = list_first_entry_or_null(&pgtable->lru,
+ struct page, lru);
+ if (page_huge_pte(page))
+ list_del(&pgtable->lru);
+ return page_to_virt(pgtable);
+}
+
+static int vmemmap_pgtable_prealloc(struct hstate *h, struct page *page)
+{
+ int i;
+ pte_t *pte_p;
+ unsigned int nr = nr_pgtable(h);
+
+ if (!nr)
+ return 0;
+
+ vmemmap_pgtable_init(page);
+
+ for (i = 0; i < nr; i++) {
+ pte_p = pte_alloc_one_kernel(&init_mm);
+ if (!pte_p)
+ goto out;
+ vmemmap_pgtable_deposit(page, pte_p);
+ }
+
+ return 0;
+out:
+ while (i-- && (pte_p = vmemmap_pgtable_withdraw(page)))
+ pte_free_kernel(&init_mm, pte_p);
+ return -ENOMEM;
+}
+
+static inline void vmemmap_pgtable_free(struct hstate *h, struct page *page)
+{
+ pte_t *pte_p;
+
+ if (!nr_pgtable(h))
+ return;
+
+ while ((pte_p = vmemmap_pgtable_withdraw(page)))
+ pte_free_kernel(&init_mm, pte_p);
+}
+
static void __init hugetlb_vmemmap_init(struct hstate *h)
{
unsigned int order = huge_page_order(h);
@@ -1323,6 +1420,15 @@ static void __init hugetlb_vmemmap_init(struct hstate *h)
static inline void hugetlb_vmemmap_init(struct hstate *h)
{
}
+
+static inline int vmemmap_pgtable_prealloc(struct hstate *h, struct page *page)
+{
+ return 0;
+}
+
+static inline void vmemmap_pgtable_free(struct hstate *h, struct page *page)
+{
+}
#endif
static void update_and_free_page(struct hstate *h, struct page *page)
@@ -1531,6 +1637,9 @@ void free_huge_page(struct page *page)
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
{
+ /* Must be called before the initialization of @page->lru */
+ vmemmap_pgtable_free(h, page);
+
INIT_LIST_HEAD(&page->lru);
set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
set_hugetlb_cgroup(page, NULL);
@@ -1783,6 +1892,14 @@ static struct page *alloc_fresh_huge_page(struct hstate *h,
if (!page)
return NULL;
+ if (vmemmap_pgtable_prealloc(h, page)) {
+ if (hstate_is_gigantic(h))
+ free_gigantic_page(page, huge_page_order(h));
+ else
+ put_page(page);
+ return NULL;
+ }
+
if (hstate_is_gigantic(h))
prep_compound_gigantic_page(page, huge_page_order(h));
prep_new_huge_page(h, page, page_to_nid(page));
--
2.20.1
next prev parent reply other threads:[~2020-09-16 0:44 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 12:59 [RFC PATCH 00/24] mm/hugetlb: Free some vmemmap pages of hugetlb page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 01/24] mm/memory_hotplug: Move bootmem info registration API to bootmem_info.c Muchun Song
2020-09-29 22:46 ` Mike Kravetz
2020-09-15 12:59 ` [RFC PATCH 02/24] mm/memory_hotplug: Move {get,put}_page_bootmem() " Muchun Song
2020-09-29 23:30 ` Mike Kravetz
2020-09-15 12:59 ` [RFC PATCH 03/24] mm/hugetlb: Introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2020-09-16 2:13 ` Randy Dunlap
2020-09-29 23:41 ` Mike Kravetz
2020-09-30 2:56 ` [External] " Muchun Song
2020-09-30 2:56 ` Muchun Song
2020-09-15 12:59 ` [RFC PATCH 04/24] mm/hugetlb: Register bootmem info when CONFIG_HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2020-09-15 12:59 ` [RFC PATCH 05/24] mm/hugetlb: Introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
2020-09-30 22:41 ` Mike Kravetz
2020-10-01 2:57 ` [External] " Muchun Song
2020-10-01 2:57 ` Muchun Song
2020-09-15 12:59 ` Muchun Song [this message]
2020-09-15 12:59 ` [RFC PATCH 07/24] mm/hugetlb: Add freeing unused vmemmap pages support for x86 Muchun Song
2020-09-15 12:59 ` [RFC PATCH 08/24] mm/bootmem_info: Introduce {free,prepare}_vmemmap_page() Muchun Song
2020-09-15 12:59 ` [RFC PATCH 09/24] x86/mm: Introduce VMEMMAP_SIZE/VMEMMAP_END macro Muchun Song
2020-09-15 12:59 ` [RFC PATCH 10/24] mm/hugetlb: Free the vmemmap pages associated with each hugetlb page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 11/24] mm/hugetlb: Add vmemmap_pmd_huge macro for x86 Muchun Song
2020-09-15 12:59 ` [RFC PATCH 12/24] mm/hugetlb: Defer freeing of hugetlb pages Muchun Song
2020-09-15 12:59 ` [RFC PATCH 13/24] mm/hugetlb: Allocate the vmemmap pages associated with each hugetlb page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 14/24] mm/hugetlb: Introduce remap_huge_page_pmd_vmemmap helper Muchun Song
2020-09-15 12:59 ` [RFC PATCH 15/24] mm/hugetlb: Use PG_slab to indicate split pmd Muchun Song
2020-09-15 12:59 ` [RFC PATCH 16/24] mm/hugetlb: Support freeing vmemmap pages of gigantic page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 17/24] mm/hugetlb: Add a BUILD_BUG_ON to check if struct page size is a power of two Muchun Song
2020-09-15 12:59 ` [RFC PATCH 18/24] mm/hugetlb: Clear PageHWPoison on the non-error memory page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 19/24] mm/hugetlb: Flush work when dissolving hugetlb page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 20/24] mm/hugetlb: Add a kernel parameter hugetlb_free_vmemmap Muchun Song
2020-09-16 2:10 ` Randy Dunlap
2020-09-16 2:50 ` [External] " Muchun Song
2020-09-16 2:50 ` Muchun Song
2020-09-15 12:59 ` [RFC PATCH 21/24] mm/hugetlb: Merge pte to huge pmd only for gigantic page Muchun Song
2020-09-20 9:59 ` Muchun Song
2020-09-20 9:59 ` Muchun Song
2020-09-15 12:59 ` [RFC PATCH 22/24] mm/hugetlb: Implement vmemmap_pmd_mkhuge macro Muchun Song
2020-09-15 12:59 ` [RFC PATCH 23/24] mm/hugetlb: Gather discrete indexes of tail page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 24/24] mm/hugetlb: Add BUILD_BUG_ON to catch invalid usage of tail struct page Muchun Song
2020-09-15 14:32 ` [RFC PATCH 00/24] mm/hugetlb: Free some vmemmap pages of hugetlb page Matthew Wilcox
2020-09-15 14:53 ` Dave Hansen
2020-09-15 15:28 ` [External] " Muchun Song
2020-09-15 15:28 ` Muchun Song
2020-09-15 15:42 ` Matthew Wilcox
2020-09-15 17:32 ` Muchun Song
2020-09-15 17:32 ` Muchun Song
2020-09-15 17:39 ` Matthew Wilcox
2020-09-15 18:03 ` Muchun Song
2020-09-15 18:03 ` Muchun Song
2020-09-15 18:15 ` Matthew Wilcox
2020-09-16 2:45 ` Muchun Song
2020-09-16 2:45 ` Muchun Song
2020-09-29 21:58 ` Mike Kravetz
2020-09-30 3:13 ` Matthew Wilcox
2020-10-07 21:12 ` Mike Kravetz
2020-10-09 4:13 ` [External] " Muchun Song
2020-10-09 4:13 ` Muchun Song
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