linux-kernel - [RFC PATCH 14/24] mm/hugetlb: Introduce remap_huge_page_pmd

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Message-Id: <20200915125947.26204-15-songmuchun@bytedance.com>
Date:   Tue, 15 Sep 2020 20:59:37 +0800
From:   Muchun Song <songmuchun@...edance.com>
To:     corbet@....net, mike.kravetz@...cle.com, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, x86@...nel.org, hpa@...or.com,
        dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
        viro@...iv.linux.org.uk, akpm@...ux-foundation.org,
        paulmck@...nel.org, mchehab+huawei@...nel.org,
        pawan.kumar.gupta@...ux.intel.com, rdunlap@...radead.org,
        oneukum@...e.com, anshuman.khandual@....com, jroedel@...e.de,
        almasrymina@...gle.com, rientjes@...gle.com
Cc:     linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
        Muchun Song <songmuchun@...edance.com>
Subject: [RFC PATCH 14/24] mm/hugetlb: Introduce remap_huge_page_pmd_vmemmap helper

The __free_huge_page_pmd_vmemmap and __remap_huge_page_pmd_vmemmap are
almost the same code. So introduce remap_free_huge_page_pmd_vmemmap
helper to simplify the code.

Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
 mm/hugetlb.c | 98 +++++++++++++++++++++-------------------------------
 1 file changed, 39 insertions(+), 59 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d0f09fe531fc..5cc796dc3a0a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1482,6 +1482,41 @@ static inline int freed_vmemmap_hpage_dec(struct page *page)
 	return atomic_dec_return_relaxed(&page->_mapcount) + 1;
 }
 
+typedef void (*remap_pte_fn)(struct page *reuse, pte_t *ptep,
+			     unsigned long start, unsigned int nr_pages,
+			     struct list_head *pages);
+
+static void remap_huge_page_pmd_vmemmap(struct hstate *h, pmd_t *pmd,
+					unsigned long addr,
+					struct list_head *pages,
+					remap_pte_fn remap_fn)
+{
+	unsigned long next;
+	unsigned long start = addr + RESERVE_VMEMMAP_SIZE;
+	unsigned long end = addr + nr_vmemmap_size(h);
+	struct page *reuse = NULL;
+
+	flush_cache_vunmap(start, end);
+
+	addr = start;
+	do {
+		unsigned int nr_pages;
+		pte_t *ptep;
+
+		ptep = pte_offset_kernel(pmd, addr);
+		if (!reuse) {
+			reuse = pte_page(ptep[-1]);
+			set_page_private(reuse, addr - PAGE_SIZE);
+		}
+
+		next = vmemmap_hpage_addr_end(addr, end);
+		nr_pages = (next - addr) >> PAGE_SHIFT;
+		remap_fn(reuse, ptep, addr, nr_pages, pages);
+	} while (pmd++, addr = next, addr != end);
+
+	flush_tlb_kernel_range(start, end);
+}
+
 static inline void free_vmemmap_page_list(struct list_head *list)
 {
 	struct page *page, *next;
@@ -1513,33 +1548,6 @@ static void __free_huge_page_pte_vmemmap(struct page *reuse, pte_t *ptep,
 	}
 }
 
-static void __free_huge_page_pmd_vmemmap(struct hstate *h, pmd_t *pmd,
-					 unsigned long addr,
-					 struct list_head *free_pages)
-{
-	unsigned long next;
-	unsigned long start = addr + RESERVE_VMEMMAP_NR * PAGE_SIZE;
-	unsigned long end = addr + nr_vmemmap_size(h);
-	struct page *reuse = NULL;
-
-	addr = start;
-	do {
-		unsigned int nr_pages;
-		pte_t *ptep;
-
-		ptep = pte_offset_kernel(pmd, addr);
-		if (!reuse)
-			reuse = pte_page(ptep[-1]);
-
-		next = vmemmap_hpage_addr_end(addr, end);
-		nr_pages = (next - addr) >> PAGE_SHIFT;
-		__free_huge_page_pte_vmemmap(reuse, ptep, addr, nr_pages,
-					     free_pages);
-	} while (pmd++, addr = next, addr != end);
-
-	flush_tlb_kernel_range(start, end);
-}
-
 static void split_vmemmap_pmd(pmd_t *pmd, pte_t *pte_p, unsigned long addr)
 {
 	struct mm_struct *mm = &init_mm;
@@ -1639,7 +1647,8 @@ static void free_huge_page_vmemmap(struct hstate *h, struct page *head)
 		split_vmemmap_huge_page(head, pmd);
 	}
 
-	__free_huge_page_pmd_vmemmap(h, pmd, (unsigned long)head, &free_pages);
+	remap_huge_page_pmd_vmemmap(h, pmd, (unsigned long)head, &free_pages,
+				    __free_huge_page_pte_vmemmap);
 	freed_vmemmap_hpage_inc(pmd_page(*pmd));
 	spin_unlock(ptl);
 
@@ -1679,35 +1688,6 @@ static void __remap_huge_page_pte_vmemmap(struct page *reuse, pte_t *ptep,
 	}
 }
 
-static void __remap_huge_page_pmd_vmemmap(struct hstate *h, pmd_t *pmd,
-					  unsigned long addr,
-					  struct list_head *remap_pages)
-{
-	unsigned long next;
-	unsigned long start = addr + RESERVE_VMEMMAP_NR * PAGE_SIZE;
-	unsigned long end = addr + nr_vmemmap_size(h);
-	struct page *reuse = NULL;
-
-	addr = start;
-	do {
-		unsigned int nr_pages;
-		pte_t *ptep;
-
-		ptep = pte_offset_kernel(pmd, addr);
-		if (!reuse) {
-			reuse = pte_page(ptep[-1]);
-			set_page_private(reuse, addr - PAGE_SIZE);
-		}
-
-		next = vmemmap_hpage_addr_end(addr, end);
-		nr_pages = (next - addr) >> PAGE_SHIFT;
-		__remap_huge_page_pte_vmemmap(reuse, ptep, addr, nr_pages,
-					      remap_pages);
-	} while (pmd++, addr = next, addr != end);
-
-	flush_tlb_kernel_range(start, end);
-}
-
 static inline void alloc_vmemmap_pages(struct hstate *h, struct list_head *list)
 {
 	int i;
@@ -1736,8 +1716,8 @@ static void alloc_huge_page_vmemmap(struct hstate *h, struct page *head)
 	ptl = vmemmap_pmd_lockptr(pmd);
 
 	spin_lock(ptl);
-	__remap_huge_page_pmd_vmemmap(h, pmd, (unsigned long)head,
-				      &remap_pages);
+	remap_huge_page_pmd_vmemmap(h, pmd, (unsigned long)head, &remap_pages,
+				    __remap_huge_page_pte_vmemmap);
 	if (!freed_vmemmap_hpage_dec(pmd_page(*pmd))) {
 		/*
 		 * Todo:
-- 
2.20.1