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bb18782aa4
Currently adding a buffer to the ioend and then building a bio from the buffer list are two separate operations. We don't build the bios and submit them until the ioend is submitted, and this places a fixed dependency on bufferhead chaining in the ioend. The first step to removing the bufferhead chaining in the ioend is on the IO submission side. We can build the bio directly as we add the buffers to the ioend chain, thereby removing the need for a latter "buffer-to-bio" submission loop. This allows us to submit bios on large ioends as soon as we cannot add more data to the bio. These bios then get captured by the active plug, and hence will be dispatched as soon as either the plug overflows or we schedule away from the writeback context. This will reduce submission latency for large IOs, but will also allow more timely request queue based writeback blocking when the device becomes congested. Signed-off-by: Dave Chinner <dchinner@redhat.com> [hch: various small updates] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
70 lines
2.6 KiB
C
70 lines
2.6 KiB
C
/*
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* Copyright (c) 2005-2006 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __XFS_AOPS_H__
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#define __XFS_AOPS_H__
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extern mempool_t *xfs_ioend_pool;
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/*
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* Types of I/O for bmap clustering and I/O completion tracking.
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*/
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enum {
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XFS_IO_INVALID, /* initial state */
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XFS_IO_DELALLOC, /* covers delalloc region */
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XFS_IO_UNWRITTEN, /* covers allocated but uninitialized data */
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XFS_IO_OVERWRITE, /* covers already allocated extent */
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};
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#define XFS_IO_TYPES \
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{ XFS_IO_INVALID, "invalid" }, \
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{ XFS_IO_DELALLOC, "delalloc" }, \
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{ XFS_IO_UNWRITTEN, "unwritten" }, \
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{ XFS_IO_OVERWRITE, "overwrite" }
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/*
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* xfs_ioend struct manages large extent writes for XFS.
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* It can manage several multi-page bio's at once.
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*/
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typedef struct xfs_ioend {
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struct list_head io_list; /* next ioend in chain */
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unsigned int io_type; /* delalloc / unwritten */
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int io_error; /* I/O error code */
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atomic_t io_remaining; /* hold count */
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struct inode *io_inode; /* file being written to */
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struct buffer_head *io_buffer_head;/* buffer linked list head */
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struct buffer_head *io_buffer_tail;/* buffer linked list tail */
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size_t io_size; /* size of the extent */
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xfs_off_t io_offset; /* offset in the file */
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struct work_struct io_work; /* xfsdatad work queue */
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struct xfs_trans *io_append_trans;/* xact. for size update */
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struct bio *io_bio; /* bio being built */
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} xfs_ioend_t;
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extern const struct address_space_operations xfs_address_space_operations;
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int xfs_get_blocks(struct inode *inode, sector_t offset,
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struct buffer_head *map_bh, int create);
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int xfs_get_blocks_direct(struct inode *inode, sector_t offset,
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struct buffer_head *map_bh, int create);
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int xfs_get_blocks_dax_fault(struct inode *inode, sector_t offset,
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struct buffer_head *map_bh, int create);
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extern void xfs_count_page_state(struct page *, int *, int *);
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extern struct block_device *xfs_find_bdev_for_inode(struct inode *);
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#endif /* __XFS_AOPS_H__ */
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