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, willy@infradead.org,
osalvador@suse.de, mhocko@suse.com, song.bao.hua@hisilicon.com
Cc: duanxiongchun@bytedance.com, 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: [PATCH v6 09/16] mm/hugetlb: Defer freeing of HugeTLB pages
Date: Tue, 24 Nov 2020 17:52:52 +0800 [thread overview]
Message-ID: <20201124095259.58755-10-songmuchun@bytedance.com> (raw)
In-Reply-To: <20201124095259.58755-1-songmuchun@bytedance.com>
In the subsequent patch, we will allocate the vmemmap pages when free
HugeTLB pages. But update_and_free_page() is called from a non-task
context(and hold hugetlb_lock), so we can defer the actual freeing in
a workqueue to prevent use GFP_ATOMIC to allocate the vmemmap pages.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
mm/hugetlb.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++------
mm/hugetlb_vmemmap.c | 5 ---
mm/hugetlb_vmemmap.h | 10 ++++++
3 files changed, 95 insertions(+), 16 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9662b5535f3a..41056b4230f1 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1221,7 +1221,7 @@ static void destroy_compound_gigantic_page(struct page *page,
__ClearPageHead(page);
}
-static void free_gigantic_page(struct page *page, unsigned int order)
+static void __free_gigantic_page(struct page *page, unsigned int order)
{
/*
* If the page isn't allocated using the cma allocator,
@@ -1288,20 +1288,100 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
{
return NULL;
}
-static inline void free_gigantic_page(struct page *page, unsigned int order) { }
+static inline void __free_gigantic_page(struct page *page,
+ unsigned int order) { }
static inline void destroy_compound_gigantic_page(struct page *page,
unsigned int order) { }
#endif
-static void update_and_free_page(struct hstate *h, struct page *page)
+static void __free_hugepage(struct hstate *h, struct page *page);
+
+/*
+ * As update_and_free_page() is be called from a non-task context(and hold
+ * hugetlb_lock), we can defer the actual freeing in a workqueue to prevent
+ * use GFP_ATOMIC to allocate a lot of vmemmap pages.
+ *
+ * update_hpage_vmemmap_workfn() locklessly retrieves the linked list of
+ * pages to be freed and frees them one-by-one. As the page->mapping pointer
+ * is going to be cleared in update_hpage_vmemmap_workfn() anyway, it is
+ * reused as the llist_node structure of a lockless linked list of huge
+ * pages to be freed.
+ */
+static LLIST_HEAD(hpage_update_freelist);
+
+static void update_hpage_vmemmap_workfn(struct work_struct *work)
{
- int i;
+ struct llist_node *node;
+ struct page *page;
+
+ node = llist_del_all(&hpage_update_freelist);
+
+ while (node) {
+ page = container_of((struct address_space **)node,
+ struct page, mapping);
+ node = node->next;
+ page->mapping = NULL;
+ __free_hugepage(page_hstate(page), page);
+ cond_resched();
+ }
+}
+static DECLARE_WORK(hpage_update_work, update_hpage_vmemmap_workfn);
+
+static inline void __update_and_free_page(struct hstate *h, struct page *page)
+{
+ /* No need to allocate vmemmap pages */
+ if (!free_vmemmap_pages_per_hpage(h)) {
+ __free_hugepage(h, page);
+ return;
+ }
+
+ /*
+ * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap
+ * pages.
+ *
+ * Only call schedule_work() if hpage_update_freelist is previously
+ * empty. Otherwise, schedule_work() had been called but the workfn
+ * hasn't retrieved the list yet.
+ */
+ if (llist_add((struct llist_node *)&page->mapping,
+ &hpage_update_freelist))
+ schedule_work(&hpage_update_work);
+}
+
+#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
+static inline void free_gigantic_page(struct hstate *h, struct page *page)
+{
+ __free_gigantic_page(page, huge_page_order(h));
+}
+#else
+static inline void free_gigantic_page(struct hstate *h, struct page *page)
+{
+ /*
+ * Temporarily drop the hugetlb_lock, because
+ * we might block in __free_gigantic_page().
+ */
+ spin_unlock(&hugetlb_lock);
+ __free_gigantic_page(page, huge_page_order(h));
+ spin_lock(&hugetlb_lock);
+}
+#endif
+
+static void update_and_free_page(struct hstate *h, struct page *page)
+{
if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
return;
h->nr_huge_pages--;
h->nr_huge_pages_node[page_to_nid(page)]--;
+
+ __update_and_free_page(h, page);
+}
+
+static void __free_hugepage(struct hstate *h, struct page *page)
+{
+ int i;
+
for (i = 0; i < pages_per_huge_page(h); i++) {
page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
1 << PG_referenced | 1 << PG_dirty |
@@ -1313,14 +1393,8 @@ static void update_and_free_page(struct hstate *h, struct page *page)
set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
set_page_refcounted(page);
if (hstate_is_gigantic(h)) {
- /*
- * Temporarily drop the hugetlb_lock, because
- * we might block in free_gigantic_page().
- */
- spin_unlock(&hugetlb_lock);
destroy_compound_gigantic_page(page, huge_page_order(h));
- free_gigantic_page(page, huge_page_order(h));
- spin_lock(&hugetlb_lock);
+ free_gigantic_page(h, page);
} else {
__free_pages(page, huge_page_order(h));
}
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 1576f69bd1d3..f6ba288966d4 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -124,11 +124,6 @@
(__boundary - 1 < (end) - 1) ? __boundary : (end); \
})
-static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h)
-{
- return h->nr_free_vmemmap_pages;
-}
-
static inline unsigned int vmemmap_pages_per_hpage(struct hstate *h)
{
return free_vmemmap_pages_per_hpage(h) + RESERVE_VMEMMAP_NR;
diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h
index 67113b67495f..293897b9f1d8 100644
--- a/mm/hugetlb_vmemmap.h
+++ b/mm/hugetlb_vmemmap.h
@@ -13,6 +13,11 @@
#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
void __init hugetlb_vmemmap_init(struct hstate *h);
void free_huge_page_vmemmap(struct hstate *h, struct page *head);
+
+static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h)
+{
+ return h->nr_free_vmemmap_pages;
+}
#else
static inline void hugetlb_vmemmap_init(struct hstate *h)
{
@@ -21,5 +26,10 @@ static inline void hugetlb_vmemmap_init(struct hstate *h)
static inline void free_huge_page_vmemmap(struct hstate *h, struct page *head)
{
}
+
+static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h)
+{
+ return 0;
+}
#endif /* CONFIG_HUGETLB_PAGE_FREE_VMEMMAP */
#endif /* _LINUX_HUGETLB_VMEMMAP_H */
--
2.11.0
next prev parent reply other threads:[~2020-11-24 9:58 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 9:52 [PATCH v6 00/16] Free some vmemmap pages of hugetlb page Muchun Song
2020-11-24 9:52 ` [PATCH v6 01/16] mm/memory_hotplug: Move bootmem info registration API to bootmem_info.c Muchun Song
2021-06-10 12:15 ` chengkaitao
2020-11-24 9:52 ` [PATCH v6 02/16] mm/memory_hotplug: Move {get,put}_page_bootmem() " Muchun Song
2020-11-24 9:52 ` [PATCH v6 03/16] mm/hugetlb: Introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2020-11-24 9:52 ` [PATCH v6 04/16] mm/hugetlb: Introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
2020-11-24 9:52 ` [PATCH v6 05/16] mm/bootmem_info: Introduce {free,prepare}_vmemmap_page() Muchun Song
2020-11-24 9:52 ` [PATCH v6 06/16] mm/hugetlb: Disable freeing vmemmap if struct page size is not power of two Muchun Song
2020-11-24 9:52 ` [PATCH v6 07/16] x86/mm/64: Disable PMD page mapping of vmemmap Muchun Song
2020-11-24 10:24 ` Oscar Salvador
2020-11-24 10:31 ` Song Bao Hua (Barry Song)
2020-11-24 11:13 ` [External] " Muchun Song
2020-11-24 9:52 ` [PATCH v6 08/16] mm/hugetlb: Free the vmemmap pages associated with each hugetlb page Muchun Song
2020-11-24 9:52 ` Muchun Song [this message]
2020-11-24 11:51 ` [PATCH v6 09/16] mm/hugetlb: Defer freeing of HugeTLB pages Michal Hocko
2020-11-24 12:45 ` [External] " Muchun Song
2020-11-24 13:14 ` Michal Hocko
2020-11-24 9:52 ` [PATCH v6 10/16] mm/hugetlb: Allocate the vmemmap pages associated with each hugetlb page Muchun Song
2020-11-24 9:52 ` [PATCH v6 11/16] mm/hugetlb: Introduce remap_huge_page_pmd_vmemmap helper Muchun Song
2020-11-24 9:52 ` [PATCH v6 12/16] mm/hugetlb: Set the PageHWPoison to the raw error page Muchun Song
2020-11-24 9:52 ` [PATCH v6 13/16] mm/hugetlb: Flush work when dissolving hugetlb page Muchun Song
2020-11-24 9:52 ` [PATCH v6 14/16] mm/hugetlb: Add a kernel parameter hugetlb_free_vmemmap Muchun Song
2020-11-24 10:53 ` Song Bao Hua (Barry Song)
2020-11-24 11:07 ` [External] " Muchun Song
2020-11-24 9:52 ` [PATCH v6 15/16] mm/hugetlb: Gather discrete indexes of tail page Muchun Song
2020-11-24 9:52 ` [PATCH v6 16/16] mm/hugetlb: Add BUILD_BUG_ON to catch invalid usage of tail struct page Muchun Song
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