diff mbox series

[030/156] fs: add a filesystem flag for THPs

Message ID 20201016024240.fjBxAsKVY%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [001/156] device-dax/kmem: fix resource release | expand

Commit Message

Andrew Morton Oct. 16, 2020, 2:42 a.m. UTC 
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: fs: add a filesystem flag for THPs

The page cache needs to know whether the filesystem supports THPs so that
it doesn't send THPs to filesystems which can't handle them.  Dave Chinner
points out that getting from the page mapping to the filesystem type is
too many steps (mapping->host->i_sb->s_type->fs_flags) so cache that
information in the address space flags.

Link: https://lkml.kernel.org/r/20200916032717.22917-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/inode.c              |    2 ++
 include/linux/fs.h      |    1 +
 include/linux/pagemap.h |    6 ++++++
 mm/shmem.c              |    2 +-
 4 files changed, 10 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/fs/inode.c~fs-add-a-filesystem-flag-for-thps
+++ a/fs/inode.c
@@ -181,6 +181,8 @@  int inode_init_always(struct super_block
 	mapping->a_ops = &empty_aops;
 	mapping->host = inode;
 	mapping->flags = 0;
+	if (sb->s_type->fs_flags & FS_THP_SUPPORT)
+		__set_bit(AS_THP_SUPPORT, &mapping->flags);
 	mapping->wb_err = 0;
 	atomic_set(&mapping->i_mmap_writable, 0);
 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
--- a/include/linux/fs.h~fs-add-a-filesystem-flag-for-thps
+++ a/include/linux/fs.h
@@ -2209,6 +2209,7 @@  struct file_system_type {
 #define FS_HAS_SUBTYPE		4
 #define FS_USERNS_MOUNT		8	/* Can be mounted by userns root */
 #define FS_DISALLOW_NOTIFY_PERM	16	/* Disable fanotify permission events */
+#define FS_THP_SUPPORT		8192	/* Remove once all fs converted */
 #define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move() during rename() internally. */
 	int (*init_fs_context)(struct fs_context *);
 	const struct fs_parameter_spec *parameters;
--- a/include/linux/pagemap.h~fs-add-a-filesystem-flag-for-thps
+++ a/include/linux/pagemap.h
@@ -29,6 +29,7 @@  enum mapping_flags {
 	AS_EXITING	= 4, 	/* final truncate in progress */
 	/* writeback related tags are not used */
 	AS_NO_WRITEBACK_TAGS = 5,
+	AS_THP_SUPPORT = 6,	/* THPs supported */
 };
 
 /**
@@ -120,6 +121,11 @@  static inline void mapping_set_gfp_mask(
 	m->gfp_mask = mask;
 }
 
+static inline bool mapping_thp_support(struct address_space *mapping)
+{
+	return test_bit(AS_THP_SUPPORT, &mapping->flags);
+}
+
 void release_pages(struct page **pages, int nr);
 
 /*
--- a/mm/shmem.c~fs-add-a-filesystem-flag-for-thps
+++ a/mm/shmem.c
@@ -3984,7 +3984,7 @@  static struct file_system_type shmem_fs_
 	.parameters	= shmem_fs_parameters,
 #endif
 	.kill_sb	= kill_litter_super,
-	.fs_flags	= FS_USERNS_MOUNT,
+	.fs_flags	= FS_USERNS_MOUNT | FS_THP_SUPPORT,
 };
 
 int __init shmem_init(void)