ext4: use bio layer instead of buffer layer in mpage_da_submit_io
Call the block I/O layer directly instad of going through the buffer
layer. This should give us much better performance and scalability,
as well as lowering our CPU utilization when doing buffered writeback.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2283369..ca9fda6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -168,7 +168,20 @@
int pages_written;
int retval;
};
-#define EXT4_IO_UNWRITTEN 0x1
+
+/*
+ * Flags for ext4_io_end->flags
+ */
+#define EXT4_IO_END_UNWRITTEN 0x0001
+#define EXT4_IO_END_ERROR 0x0002
+
+struct ext4_io_page {
+ struct page *p_page;
+ int p_count;
+};
+
+#define MAX_IO_PAGES 128
+
typedef struct ext4_io_end {
struct list_head list; /* per-file finished IO list */
struct inode *inode; /* file being written to */
@@ -179,8 +192,18 @@
struct work_struct work; /* data work queue */
struct kiocb *iocb; /* iocb struct for AIO */
int result; /* error value for AIO */
+ int num_io_pages;
+ struct ext4_io_page *pages[MAX_IO_PAGES];
} ext4_io_end_t;
+struct ext4_io_submit {
+ int io_op;
+ struct bio *io_bio;
+ ext4_io_end_t *io_end;
+ struct ext4_io_page *io_page;
+ sector_t io_next_block;
+};
+
/*
* Special inodes numbers
*/
@@ -2044,6 +2067,17 @@
__u64 start_orig, __u64 start_donor,
__u64 len, __u64 *moved_len);
+/* page-io.c */
+extern int __init init_ext4_pageio(void);
+extern void exit_ext4_pageio(void);
+extern void ext4_free_io_end(ext4_io_end_t *io);
+extern ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags);
+extern int ext4_end_io_nolock(ext4_io_end_t *io);
+extern void ext4_io_submit(struct ext4_io_submit *io);
+extern int ext4_bio_write_page(struct ext4_io_submit *io,
+ struct page *page,
+ int len,
+ struct writeback_control *wbc);
/* BH_Uninit flag: blocks are allocated but uninitialized on disk */
enum ext4_state_bits {
