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Chris Mason fa9c0d795f Btrfs: rework allocation clustering 
Because btrfs is copy-on-write, we end up picking new locations for
blocks very often.  This makes it fairly difficult to maintain perfect
read patterns over time, but we can at least do some optimizations
for writes.

This is done today by remembering the last place we allocated and
trying to find a free space hole big enough to hold more than just one
allocation.  The end result is that we tend to write sequentially to
the drive.

This happens all the time for metadata and it happens for data
when mounted -o ssd.  But, the way we record it is fairly racey
and it tends to fragment the free space over time because we are trying
to allocate fairly large areas at once.

This commit gets rid of the races by adding a free space cluster object
with dedicated locking to make sure that only one process at a time
is out replacing the cluster.

The free space fragmentation is somewhat solved by allowing a cluster
to be comprised of smaller free space extents.  This part definitely
adds some CPU time to the cluster allocations, but it allows the allocator
to consume the small holes left behind by cow.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-03 09:47:43 -04:00
..
acl.c Btrfs: Fix checkpatch.pl warnings 2009-01-05 21:25:51 -05:00
async-thread.c Btrfs: async threads should try harder to find work 2009-02-04 09:23:24 -05:00
async-thread.h Btrfs: Add ordered async work queues 2008-11-06 22:03:00 -05:00
btrfs_inode.h Btrfs: add extra flushing for renames and truncates 2009-03-31 14:27:58 -04:00
compat.h Btrfs: drop remaining LINUX_KERNEL_VERSION checks and compat code 2009-01-06 09:38:55 -05:00
compression.c Btrfs: removed unused #include <version.h>'s 2009-01-21 10:49:16 -05:00
compression.h Btrfs: Add zlib compression support 2008-10-29 14:49:59 -04:00
crc32c.h Btrfs: Drop the hardware crc32c asm code 2009-01-07 19:56:59 -05:00
ctree.c Btrfs: Optimize locking in btrfs_next_leaf() 2009-04-03 10:14:18 -04:00
ctree.h Btrfs: rework allocation clustering 2009-04-03 09:47:43 -04:00
delayed-ref.c Btrfs: make sure btrfs_update_delayed_ref doesn't increase ref_mod 2009-03-25 09:55:11 -04:00
delayed-ref.h Btrfs: make sure btrfs_update_delayed_ref doesn't increase ref_mod 2009-03-25 09:55:11 -04:00
dir-item.c Btrfs: leave btree locks spinning more often 2009-03-24 16:14:28 -04:00
disk-io.c Btrfs: rework allocation clustering 2009-04-03 09:47:43 -04:00
disk-io.h Btrfs: leave btree locks spinning more often 2009-03-24 16:14:28 -04:00
export.c Btrfs: Fix checkpatch.pl warnings 2009-01-05 21:25:51 -05:00
export.h NFS support for btrfs - v3 2008-09-25 11:04:06 -04:00
extent_io.c Btrfs: leave btree locks spinning more often 2009-03-24 16:14:28 -04:00
extent_io.h Btrfs: leave btree locks spinning more often 2009-03-24 16:14:28 -04:00
extent_map.c Btrfs: removed unused #include <version.h>'s 2009-01-21 10:49:16 -05:00
extent_map.h Btrfs: Fix csum error for compressed data 2008-11-10 07:34:43 -05:00
extent-tree.c Btrfs: rework allocation clustering 2009-04-03 09:47:43 -04:00
file-item.c Btrfs: leave btree locks spinning more often 2009-03-24 16:14:28 -04:00
file.c Btrfs: add extra flushing for renames and truncates 2009-03-31 14:27:58 -04:00
free-space-cache.c Btrfs: rework allocation clustering 2009-04-03 09:47:43 -04:00
free-space-cache.h Btrfs: rework allocation clustering 2009-04-03 09:47:43 -04:00
hash.h Switch btrfs_name_hash() to crc32c 2008-09-25 11:04:06 -04:00
inode-item.c Btrfs: leave btree locks spinning more often 2009-03-24 16:14:28 -04:00
inode-map.c Btrfs: remove btrfs_init_path 2009-02-12 14:11:25 -05:00
inode.c Btrfs: add extra flushing for renames and truncates 2009-03-31 14:27:58 -04:00
ioctl.c Btrfs: add better -ENOSPC handling 2009-02-20 11:00:09 -05:00
ioctl.h Btrfs: fix ioctl arg size (userland incompatible change!) 2009-01-16 11:59:08 -05:00
Kconfig Btrfs: make btrfs acls selectable 2009-02-04 09:28:28 -05:00
locking.c Btrfs: leave btree locks spinning more often 2009-03-24 16:14:28 -04:00
locking.h Btrfs: fix spinlock assertions on UP systems 2009-03-09 11:45:38 -04:00
Makefile Btrfs: do extent allocation and reference count updates in the background 2009-03-24 16:14:25 -04:00
ordered-data.c Btrfs: add extra flushing for renames and truncates 2009-03-31 14:27:58 -04:00
ordered-data.h Btrfs: add extra flushing for renames and truncates 2009-03-31 14:27:58 -04:00
orphan.c Btrfs: Create orphan inode records to prevent lost files after a crash 2008-09-25 11:04:05 -04:00
print-tree.c Btrfs: Fix checkpatch.pl warnings 2009-01-05 21:25:51 -05:00
print-tree.h Btrfs: Create extent_buffer interface for large blocksizes 2008-09-25 11:03:56 -04:00
ref-cache.c Btrfs: Make btrfs_drop_snapshot work in larger and more efficient chunks 2009-02-04 09:27:02 -05:00
ref-cache.h Btrfs: Make btrfs_drop_snapshot work in larger and more efficient chunks 2009-02-04 09:27:02 -05:00
root-tree.c Btrfs: Fix checkpatch.pl warnings 2009-01-05 21:25:51 -05:00
struct-funcs.c Btrfs: Fix checkpatch.pl warnings 2009-01-05 21:25:51 -05:00
super.c Btrfs: don't clean old snapshots on sync(1) 2009-02-12 09:45:08 -05:00
sysfs.c Btrfs: Fix checkpatch.pl warnings 2009-01-05 21:25:51 -05:00
transaction.c Btrfs: rework allocation clustering 2009-04-03 09:47:43 -04:00
transaction.h Btrfs: reduce stalls during transaction commit 2009-03-24 16:14:26 -04:00
tree-defrag.c Btrfs: do extent allocation and reference count updates in the background 2009-03-24 16:14:25 -04:00
tree-log.c Btrfs: kill the pinned_mutex 2009-04-03 10:14:18 -04:00
tree-log.h Btrfs: tree logging unlink/rename fixes 2009-03-24 16:14:52 -04:00
version.h Update Btrfs files for in-kernel usage 2008-09-25 15:41:59 -04:00
version.sh Btrfs: Fixes for 2.6.28-rc API changes 2008-11-19 21:17:22 -05:00
volumes.c Btrfs: unplug in the async bio submission threads 2009-04-03 10:32:58 -04:00
volumes.h Btrfs: shared seed device 2008-12-12 10:03:26 -05:00
xattr.c Btrfs: selinux support 2009-02-04 09:29:13 -05:00
xattr.h Btrfs: selinux support 2009-02-04 09:29:13 -05:00
zlib.c Btrfs: Fix checkpatch.pl warnings 2009-01-05 21:25:51 -05:00