kernel_optimize_test/fs/xfs/linux-2.6/xfs_sysctl.h
David Chinner 2a82b8be8a [XFS] Concurrent Multi-File Data Streams
In media spaces, video is often stored in a frame-per-file format. When
dealing with uncompressed realtime HD video streams in this format, it is
crucial that files do not get fragmented and that multiple files a placed
contiguously on disk.

When multiple streams are being ingested and played out at the same time,
it is critical that the filesystem does not cross the streams and
interleave them together as this creates seek and readahead cache miss
latency and prevents both ingest and playout from meeting frame rate
targets.

This patch set creates a "stream of files" concept into the allocator to
place all the data from a single stream contiguously on disk so that RAID
array readahead can be used effectively. Each additional stream gets
placed in different allocation groups within the filesystem, thereby
ensuring that we don't cross any streams. When an AG fills up, we select a
new AG for the stream that is not in use.

The core of the functionality is the stream tracking - each inode that we
create in a directory needs to be associated with the directories' stream.
Hence every time we create a file, we look up the directories' stream
object and associate the new file with that object.

Once we have a stream object for a file, we use the AG that the stream
object point to for allocations. If we can't allocate in that AG (e.g. it
is full) we move the entire stream to another AG. Other inodes in the same
stream are moved to the new AG on their next allocation (i.e. lazy
update).

Stream objects are kept in a cache and hold a reference on the inode.
Hence the inode cannot be reclaimed while there is an outstanding stream
reference. This means that on unlink we need to remove the stream
association and we also need to flush all the associations on certain
events that want to reclaim all unreferenced inodes (e.g. filesystem
freeze).

SGI-PV: 964469
SGI-Modid: xfs-linux-melb:xfs-kern:29096a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Barry Naujok <bnaujok@sgi.com>
Signed-off-by: Donald Douwsma <donaldd@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
Signed-off-by: Vlad Apostolov <vapo@sgi.com>
2007-07-14 15:40:53 +10:00

104 lines
3.4 KiB
C

/*
* Copyright (c) 2001-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_SYSCTL_H__
#define __XFS_SYSCTL_H__
#include <linux/sysctl.h>
/*
* Tunable xfs parameters
*/
typedef struct xfs_sysctl_val {
int min;
int val;
int max;
} xfs_sysctl_val_t;
typedef struct xfs_param {
xfs_sysctl_val_t restrict_chown;/* Root/non-root can give away files.*/
xfs_sysctl_val_t sgid_inherit; /* Inherit S_ISGID if process' GID is
* not a member of parent dir GID. */
xfs_sysctl_val_t symlink_mode; /* Link creat mode affected by umask */
xfs_sysctl_val_t panic_mask; /* bitmask to cause panic on errors. */
xfs_sysctl_val_t error_level; /* Degree of reporting for problems */
xfs_sysctl_val_t syncd_timer; /* Interval between xfssyncd wakeups */
xfs_sysctl_val_t stats_clear; /* Reset all XFS statistics to zero. */
xfs_sysctl_val_t inherit_sync; /* Inherit the "sync" inode flag. */
xfs_sysctl_val_t inherit_nodump;/* Inherit the "nodump" inode flag. */
xfs_sysctl_val_t inherit_noatim;/* Inherit the "noatime" inode flag. */
xfs_sysctl_val_t xfs_buf_timer; /* Interval between xfsbufd wakeups. */
xfs_sysctl_val_t xfs_buf_age; /* Metadata buffer age before flush. */
xfs_sysctl_val_t inherit_nosym; /* Inherit the "nosymlinks" flag. */
xfs_sysctl_val_t rotorstep; /* inode32 AG rotoring control knob */
xfs_sysctl_val_t inherit_nodfrg;/* Inherit the "nodefrag" inode flag. */
xfs_sysctl_val_t fstrm_timer; /* Filestream dir-AG assoc'n timeout. */
} xfs_param_t;
/*
* xfs_error_level:
*
* How much error reporting will be done when internal problems are
* encountered. These problems normally return an EFSCORRUPTED to their
* caller, with no other information reported.
*
* 0 No error reports
* 1 Report EFSCORRUPTED errors that will cause a filesystem shutdown
* 5 Report all EFSCORRUPTED errors (all of the above errors, plus any
* additional errors that are known to not cause shutdowns)
*
* xfs_panic_mask bit 0x8 turns the error reports into panics
*/
enum {
/* XFS_REFCACHE_SIZE = 1 */
/* XFS_REFCACHE_PURGE = 2 */
XFS_RESTRICT_CHOWN = 3,
XFS_SGID_INHERIT = 4,
XFS_SYMLINK_MODE = 5,
XFS_PANIC_MASK = 6,
XFS_ERRLEVEL = 7,
XFS_SYNCD_TIMER = 8,
/* XFS_PROBE_DMAPI = 9 */
/* XFS_PROBE_IOOPS = 10 */
/* XFS_PROBE_QUOTA = 11 */
XFS_STATS_CLEAR = 12,
XFS_INHERIT_SYNC = 13,
XFS_INHERIT_NODUMP = 14,
XFS_INHERIT_NOATIME = 15,
XFS_BUF_TIMER = 16,
XFS_BUF_AGE = 17,
/* XFS_IO_BYPASS = 18 */
XFS_INHERIT_NOSYM = 19,
XFS_ROTORSTEP = 20,
XFS_INHERIT_NODFRG = 21,
XFS_FILESTREAM_TIMER = 22,
};
extern xfs_param_t xfs_params;
#ifdef CONFIG_SYSCTL
extern void xfs_sysctl_register(void);
extern void xfs_sysctl_unregister(void);
#else
# define xfs_sysctl_register() do { } while (0)
# define xfs_sysctl_unregister() do { } while (0)
#endif /* CONFIG_SYSCTL */
#endif /* __XFS_SYSCTL_H__ */