ascend: share_pool: Use sharepool_no_page to alloc hugepage

ascend inclusion
category: feature
bugzilla: NA
CVE: NA

-------------------------------------------------

Sharepool applies for a dedicated interface for large pages,
which optimizes the efficiency of memory application
Reviewed-by: NDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

include/linux/hugetlb.h

@@ -645,4 +645,8 @@ static inline spinlock_t *huge_pte_lock(struct hstate *h,
 	return ptl;
 }
 
+#ifdef CONFIG_ASCEND_SHARE_POOL
+pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, int writable);
+#endif
+
 #endif /* _LINUX_HUGETLB_H */

include/linux/share_pool.h

@@ -220,6 +220,11 @@ static inline void sp_dump_stack(void)
 		dump_stack();
 }
 
+vm_fault_t sharepool_no_page(struct mm_struct *mm,
+			struct vm_area_struct *vma,
+			struct address_space *mapping, pgoff_t idx,
+			unsigned long address, pte_t *ptep, unsigned int flags);
+
 #else
 
 static inline int sp_group_add_task(int pid, int spg_id)

mm/hugetlb.c

@@ -3352,8 +3352,13 @@ const struct vm_operations_struct hugetlb_vm_ops = {
 	.pagesize = hugetlb_vm_op_pagesize,
 };
 
+#ifdef CONFIG_ASCEND_SHARE_POOL
+pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
+				int writable)
+#else
 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
 				int writable)
+#endif
 {
 	pte_t entry;
 
@@ -3370,6 +3375,9 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
 
 	return entry;
 }
+#ifdef CONFIG_ASCEND_SHARE_POOL
+EXPORT_SYMBOL(make_huge_pte);
+#endif
 
 static void set_huge_ptep_writable(struct vm_area_struct *vma,
 				   unsigned long address, pte_t *ptep)
@@ -3962,12 +3970,6 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
 		}
 
 		page = alloc_huge_page(vma, haddr, 0);
-		if (IS_ERR(page) && sp_check_vm_share_pool(vma->vm_flags)) {
-			page = alloc_huge_page_node(hstate_file(vma->vm_file),
-						    numa_mem_id());
-			if (!page)
-				page = ERR_PTR(-ENOMEM);
-		}
 		if (IS_ERR(page)) {
 			/*
 			 * Returning error will result in faulting task being
@@ -4155,7 +4157,15 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	entry = huge_ptep_get(ptep);
 	if (huge_pte_none(entry)) {
+#ifdef CONFIG_ASCEND_SHARE_POOL
+		if (sp_check_vm_share_pool(vma->vm_flags)) {
+			ret = sharepool_no_page(mm, vma, mapping, idx, address, ptep, flags);
+		} else {
 			ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
+		}
+#else
+		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
+#endif
 		goto out_mutex;
 	}
 

mm/share_pool.c

@@ -41,6 +41,8 @@
 #include <linux/idr.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/rmap.h>
+#include <linux/hugetlb.h>
 
 /* access control mode macros  */
 #define AC_NONE			0
@@ -2399,6 +2401,94 @@ static int spa_stat_show(struct seq_file *seq, void *offset)
 	return 0;
 }
 
+vm_fault_t sharepool_no_page(struct mm_struct *mm,
+			struct vm_area_struct *vma,
+			struct address_space *mapping, pgoff_t idx,
+			unsigned long address, pte_t *ptep, unsigned int flags)
+{
+	struct hstate *h = hstate_vma(vma);
+	vm_fault_t ret = VM_FAULT_SIGBUS;
+	unsigned long size;
+	struct page *page;
+	pte_t new_pte;
+	spinlock_t *ptl;
+	unsigned long haddr = address & huge_page_mask(h);
+	bool new_page = false;
+	int err;
+
+retry:
+	page = find_lock_page(mapping, idx);
+	if (!page) {
+		size = i_size_read(mapping->host) >> huge_page_shift(h);
+		if (idx >= size)
+			goto out;
+
+		page = alloc_huge_page(vma, haddr, 0);
+		if (IS_ERR(page)) {
+			page = alloc_huge_page_node(hstate_file(vma->vm_file),
+						    numa_mem_id());
+			if (!page)
+				page = ERR_PTR(-ENOMEM);
+		}
+		if (IS_ERR(page)) {
+			ptl = huge_pte_lock(h, mm, ptep);
+			if (!huge_pte_none(huge_ptep_get(ptep))) {
+				ret = 0;
+				spin_unlock(ptl);
+				goto out;
+			}
+			spin_unlock(ptl);
+			ret = vmf_error(PTR_ERR(page));
+			goto out;
+		}
+		__SetPageUptodate(page);
+		new_page = true;
+
+		/* sharepool pages are all shared */
+		err = huge_add_to_page_cache(page, mapping, idx);
+		if (err) {
+			put_page(page);
+			if (err == -EEXIST)
+				goto retry;
+			goto out;
+		}
+	}
+
+
+	ptl = huge_pte_lock(h, mm, ptep);
+	size = i_size_read(mapping->host) >> huge_page_shift(h);
+	if (idx >= size)
+		goto backout;
+
+	ret = 0;
+	if (!huge_pte_none(huge_ptep_get(ptep)))
+		goto backout;
+
+	page_dup_rmap(page, true);
+	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
+				&& (vma->vm_flags & VM_SHARED)));
+	set_huge_pte_at(mm, haddr, ptep, new_pte);
+
+	hugetlb_count_add(pages_per_huge_page(h), mm);
+
+	spin_unlock(ptl);
+
+	if (new_page) {
+		SetPagePrivate(&page[1]);
+	}
+
+	unlock_page(page);
+out:
+	return ret;
+
+backout:
+	spin_unlock(ptl);
+	unlock_page(page);
+	put_page(page);
+	goto out;
+}
+EXPORT_SYMBOL(sharepool_no_page);
+
 /*
  * Called by proc_root_init() to initialize the /proc/sharepool subtree
  */