[PATCHv6 13/22] mm, vfs: introduce i_split_sem
From: Kirill A. Shutemov <hidden>
Date: 2013-09-23 12:05:41
Also in:
linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), memory management - thp (transparent huge page), the rest · Maintainers:
Alexander Viro, Christian Brauner, Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Linus Torvalds
i_split_sem taken on read will protect hugepages in inode's pagecache against splitting. i_split_sem will be taken on write during splitting. Signed-off-by: Kirill A. Shutemov <redacted> --- fs/inode.c | 3 +++ include/linux/fs.h | 3 +++ include/linux/huge_mm.h | 10 ++++++++++ 3 files changed, 16 insertions(+)
diff --git a/fs/inode.c b/fs/inode.c
index b33ba8e021..ea06e378c6 100644
--- a/fs/inode.c
+++ b/fs/inode.c@@ -162,6 +162,9 @@ int inode_init_always(struct super_block *sb, struct inode *inode) atomic_set(&inode->i_dio_count, 0); +#ifdef CONFIG_TRANSPARENT_HUGEPAGE_PAGECACHE + init_rwsem(&inode->i_split_sem); +#endif mapping->a_ops = &empty_aops; mapping->host = inode; mapping->flags = 0;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3f40547ba1..26801f0bb1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -610,6 +610,9 @@ struct inode { atomic_t i_readcount; /* struct files open RO */ #endif void *i_private; /* fs or device private pointer */ +#ifdef CONFIG_TRANSPARENT_HUGEPAGE_PAGECACHE + struct rw_semaphore i_split_sem; +#endif }; static inline int inode_unhashed(struct inode *inode)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 3700ada4d2..ce9fcae8ef 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h@@ -241,12 +241,22 @@ static inline int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_str #define HPAGE_CACHE_NR (1L << HPAGE_CACHE_ORDER) #define HPAGE_CACHE_INDEX_MASK (HPAGE_CACHE_NR - 1) +#define i_split_down_read(inode) down_read(&inode->i_split_sem) +#define i_split_up_read(inode) up_read(&inode->i_split_sem) + #else #define HPAGE_CACHE_ORDER ({ BUILD_BUG(); 0; }) #define HPAGE_CACHE_NR ({ BUILD_BUG(); 0; }) #define HPAGE_CACHE_INDEX_MASK ({ BUILD_BUG(); 0; }) +static inline void i_split_down_read(struct inode *inode) +{ +} + +static inline void i_split_up_read(struct inode *inode) +{ +} #endif static inline bool transparent_hugepage_pagecache(void)
--
1.8.4.rc3
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