[RFC v3 PATCH 04/10] mm/hugetlb: expose hugetlb fault mutex for use by fallocate
From: Mike Kravetz <hidden>
Date: 2015-05-21 15:49:54
Also in:
lkml
Subsystem:
hugetlb subsystem, memory management, the rest · Maintainers:
Muchun Song, Oscar Salvador, Andrew Morton, Linus Torvalds
hugetlb page faults are currently synchronized by the table of mutexes (htlb_fault_mutex_table). fallocate code will need to synchronize with the page fault code when it allocates or deletes pages. Expose interfaces so that fallocate operations can be synchronized with page faults. Signed-off-by: Mike Kravetz <redacted> --- include/linux/hugetlb.h | 3 +++ mm/hugetlb.c | 23 ++++++++++++++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index fd337f2..d0d033e 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h@@ -82,6 +82,9 @@ void putback_active_hugepage(struct page *page); bool is_hugepage_active(struct page *page); void free_huge_page(struct page *page); void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserve); +u32 hugetlb_fault_mutex_shared_hash(struct address_space *mapping, pgoff_t idx); +void hugetlb_fault_mutex_lock(u32 hash); +void hugetlb_fault_mutex_unlock(u32 hash); #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 620cc9e..df0d32a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c@@ -3183,7 +3183,8 @@ static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, unsigned long key[2]; u32 hash; - if (vma->vm_flags & VM_SHARED) { + /* !vma implies this was called from hugetlbfs fallocate code */ + if (!vma || vma->vm_flags & VM_SHARED) { key[0] = (unsigned long) mapping; key[1] = idx; } else {
@@ -3209,6 +3210,26 @@ static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, } #endif +/* + * Interfaces to the fault mutex routines for use by hugetlbfs + * fallocate code. Faults must be synchronized with page adds or + * deletes by fallocate. fallocate only deals with shared mappings. + */ +u32 hugetlb_fault_mutex_shared_hash(struct address_space *mapping, pgoff_t idx) +{ + return fault_mutex_hash(NULL, NULL, NULL, mapping, idx, 0); +} + +void hugetlb_fault_mutex_lock(u32 hash) +{ + mutex_lock(&htlb_fault_mutex_table[hash]); +} + +void hugetlb_fault_mutex_unlock(u32 hash) +{ + mutex_unlock(&htlb_fault_mutex_table[hash]); +} + int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, unsigned int flags) {
--
2.1.0
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