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Commit Graph

37597 Commits

Author SHA1 Message Date
Jeff Garzik
1bdfd554be [PATCH] SCSI: fix request flag-related build breakage
The ->flags in struct request was split into two variables, in a recent
changeset.  The merge of this change forgot to update SCSI's libsas,
probably because libsas was a very recent merge.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-30 19:33:43 -07:00
Andrew Morton
cb5d9e0948 [PATCH] scsi: device_reprobe() can fail
device_reprobe() should return an error code.  When it does so,
scsi_device_reprobe() should propagate it back.

Acked-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-30 19:33:43 -07:00
Linus Torvalds
cfae35804b Merge branch 'block' of git://brick.kernel.dk/data/git/linux-2.6-block
* 'block' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [PATCH] Only enable CONFIG_BLOCK option for embedded
2006-09-30 13:59:54 -07:00
Jens Axboe
51d7513a8a [PATCH] Only enable CONFIG_BLOCK option for embedded
It's too easy for people to shoot themselves in the foot, and it
only makes sense for embedded folks anyway.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 21:14:05 +02:00
Linus Torvalds
56f29d7fe4 Merge branch 'block' of git://brick.kernel.dk/data/git/linux-2.6-block
* 'block' of git://brick.kernel.dk/data/git/linux-2.6-block: (67 commits)
  [PATCH] blk_queue_start_tag() shared map race fix
  [PATCH] Update axboe@suse.de email address
  [PATCH] fix creating zero sized bio mempools in low memory system
  [PATCH] CONFIG_BLOCK: blk_congestion_wait() fix
  [PATCH] CONFIG_BLOCK internal.h cleanups
  [PATCH] BLOCK: Make USB storage depend on SCSI rather than selecting it [try #6]
  [PATCH] BLOCK: Make it possible to disable the block layer [try #6]
  [PATCH] BLOCK: Remove no-longer necessary linux/buffer_head.h inclusions [try #6]
  [PATCH] BLOCK: Remove no-longer necessary linux/mpage.h inclusions [try #6]
  [PATCH] BLOCK: Move the msdos device ioctl compat stuff to the msdos driver [try #6]
  [PATCH] BLOCK: Move the Ext3 device ioctl compat stuff to the Ext3 driver [try #6]
  [PATCH] BLOCK: Move the Ext2 device ioctl compat stuff to the Ext2 driver [try #6]
  [PATCH] BLOCK: Move the ReiserFS device ioctl compat stuff to the ReiserFS driver [try #6]
  [PATCH] BLOCK: Move common FS-specific ioctls to linux/fs.h [try #6]
  [PATCH] BLOCK: Move the loop device ioctl compat stuff to the loop driver [try #6]
  [PATCH] BLOCK: Move __invalidate_device() to block_dev.c [try #6]
  [PATCH] BLOCK: Dissociate generic_writepages() from mpage stuff [try #6]
  [PATCH] BLOCK: Remove dependence on existence of blockdev_superblock [try #6]
  [PATCH] BLOCK: Move extern declarations out of fs/*.c into header files [try #6]
  [PATCH] BLOCK: Don't call block_sync_page() from AFS [try #6]
  ...
2006-09-30 12:07:01 -07:00
Jens Axboe
059af497c2 [PATCH] blk_queue_start_tag() shared map race fix
If we share the tag map between two or more queues, then we cannot
use __set_bit() to set the bit. In fact we need to make sure we
atomically acquire this tag, so loop using test_and_set_bit() to
protect from that.

Noticed by Mike Christie <michaelc@cs.wisc.edu>

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:34 +02:00
Jens Axboe
0fe2347957 [PATCH] Update axboe@suse.de email address
As people often look for the copyright in files to see who to mail,
update the link to a neutral one.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:34 +02:00
Milan Broz
50be345560 [PATCH] fix creating zero sized bio mempools in low memory system
In the very low memory systems is in the init_bio call
scale parameter set to zero and it leads to creating
zero sized mempool.

This patch prevents pool_entries parameter become zero,
so the created pool have at least 1 entry.

Mempool with 0 entries lead to incorrect behaviour
of mempool_free. (Alloc requests are not waken up
and system stalls in mempool_alloc->ioschedule).

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:33 +02:00
Andrew Morton
bcfd8d3615 [PATCH] CONFIG_BLOCK: blk_congestion_wait() fix
Don't just do nothing: it'll cause busywaits all over writeback and page
reclaim.

For now, take a fixed-length nap.  Will improve when NFS starts waking up
throttled processes.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:33 +02:00
Andrew Morton
5e6d12b2c8 [PATCH] CONFIG_BLOCK internal.h cleanups
- forward declare struct superblock
- use inlines, not macros

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:32 +02:00
David Howells
65934a9a02 [PATCH] BLOCK: Make USB storage depend on SCSI rather than selecting it [try #6]
This makes CONFIG_USB_STORAGE depend on CONFIG_SCSI rather than selecting it,
as selecting it makes CONFIG_USB_STORAGE override the dependencies of SCSI,
causing it to turn on even if they aren't all met.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:32 +02:00
David Howells
9361401eb7 [PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer.  Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.

This patch does the following:

 (*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
     support.

 (*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
     an item that uses the block layer.  This includes:

     (*) Block I/O tracing.

     (*) Disk partition code.

     (*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.

     (*) The SCSI layer.  As far as I can tell, even SCSI chardevs use the
     	 block layer to do scheduling.  Some drivers that use SCSI facilities -
     	 such as USB storage - end up disabled indirectly from this.

     (*) Various block-based device drivers, such as IDE and the old CDROM
     	 drivers.

     (*) MTD blockdev handling and FTL.

     (*) JFFS - which uses set_bdev_super(), something it could avoid doing by
     	 taking a leaf out of JFFS2's book.

 (*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
     linux/elevator.h contingent on CONFIG_BLOCK being set.  sector_div() is,
     however, still used in places, and so is still available.

 (*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
     parts of linux/fs.h.

 (*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.

 (*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.

 (*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
     is not enabled.

 (*) fs/no-block.c is created to hold out-of-line stubs and things that are
     required when CONFIG_BLOCK is not set:

     (*) Default blockdev file operations (to give error ENODEV on opening).

 (*) Makes some /proc changes:

     (*) /proc/devices does not list any blockdevs.

     (*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.

 (*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.

 (*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
     given command other than Q_SYNC or if a special device is specified.

 (*) In init/do_mounts.c, no reference is made to the blockdev routines if
     CONFIG_BLOCK is not defined.  This does not prohibit NFS roots or JFFS2.

 (*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
     error ENOSYS by way of cond_syscall if so).

 (*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
     CONFIG_BLOCK is not set, since they can't then happen.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:31 +02:00
David Howells
d366e40a1c [PATCH] BLOCK: Remove no-longer necessary linux/buffer_head.h inclusions [try #6]
Remove inclusions of linux/buffer_head.h that are no longer necessary due to the
transfer of a number of things out of there.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:31 +02:00
David Howells
4cb50dc2ea [PATCH] BLOCK: Remove no-longer necessary linux/mpage.h inclusions [try #6]
Remove inclusions of linux/mpage.h that are no longer necessary due to the
transfer of generic_writepages().

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:30 +02:00
David Howells
188f83dfe0 [PATCH] BLOCK: Move the msdos device ioctl compat stuff to the msdos driver [try #6]
Move the msdos device ioctl compat stuff from fs/compat_ioctl.c to the msdos
driver so that the msdos header file doesn't need to be included.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:30 +02:00
David Howells
52a700c567 [PATCH] BLOCK: Move the Ext3 device ioctl compat stuff to the Ext3 driver [try #6]
Move the Ext3 device ioctl compat stuff from fs/compat_ioctl.c to the Ext3
driver so that the Ext3 header file doesn't need to be included.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:29 +02:00
David Howells
e322ff07fb [PATCH] BLOCK: Move the Ext2 device ioctl compat stuff to the Ext2 driver [try #6]
Move the Ext2 device ioctl compat stuff from fs/compat_ioctl.c to the Ext2
driver so that the Ext2 header file doesn't need to be included.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:29 +02:00
David Howells
52b499c438 [PATCH] BLOCK: Move the ReiserFS device ioctl compat stuff to the ReiserFS driver [try #6]
Move the ReiserFS device ioctl compat stuff from fs/compat_ioctl.c to the
ReiserFS driver so that the ReiserFS header file doesn't need to be included.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:28 +02:00
David Howells
36695673b0 [PATCH] BLOCK: Move common FS-specific ioctls to linux/fs.h [try #6]
Move common FS-specific ioctls from linux/ext2_fs.h to linux/fs.h as FS_IOC_*
and FS_IOC32_* and have the users of them use those as a base.

Also move the GETFLAGS/SETFLAGS flags to linux/fs.h as FS_*_FL macros, and then
have the other users use them as a base.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:28 +02:00
David Howells
863d5b822c [PATCH] BLOCK: Move the loop device ioctl compat stuff to the loop driver [try #6]
Move the loop device ioctl compat stuff from fs/compat_ioctl.c to the loop
driver so that the loop header file doesn't need to be included.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:27 +02:00
David Howells
b71e8a4ce0 [PATCH] BLOCK: Move __invalidate_device() to block_dev.c [try #6]
Move __invalidate_device() from fs/inode.c to fs/block_dev.c so that it can
more easily be disabled when the block layer is disabled.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:27 +02:00
David Howells
811d736f9e [PATCH] BLOCK: Dissociate generic_writepages() from mpage stuff [try #6]
Dissociate the generic_writepages() function from the mpage stuff, moving its
declaration to linux/mm.h and actually emitting a full implementation into
mm/page-writeback.c.

The implementation is a partial duplicate of mpage_writepages() with all BIO
references removed.

It is used by NFS to do writeback.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:26 +02:00
David Howells
7b0de42d7c [PATCH] BLOCK: Remove dependence on existence of blockdev_superblock [try #6]
Move blockdev_superblock extern declaration from fs/fs-writeback.c to a
headerfile and remove the dependence on it by wrapping it in a macro.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:26 +02:00
David Howells
07f3f05c1e [PATCH] BLOCK: Move extern declarations out of fs/*.c into header files [try #6]
Create a new header file, fs/internal.h, for common definitions local to the
sources in the fs/ directory.

Move extern definitions that should be in header files from fs/*.c to
fs/internal.h or other main header files where they span directories.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:18 +02:00
David Howells
65e6f5bc81 [PATCH] BLOCK: Don't call block_sync_page() from AFS [try #6]
The AFS filesystem no longer needs to override its sync_page() op.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:32:12 +02:00
David Howells
831058dec3 [PATCH] BLOCK: Separate the bounce buffering code from the highmem code [try #6]
Move the bounce buffer code from mm/highmem.c to mm/bounce.c so that it can be
more easily disabled when the block layer is disabled.

!!!NOTE!!! There may be a bug in this code: Should init_emergency_pool() be
	   contingent on CONFIG_HIGHMEM?

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:32:11 +02:00
David Howells
b398f6bff9 [PATCH] BLOCK: Stop fallback_migrate_page() from using page_has_buffers() [try #6]
Stop fallback_migrate_page() from using page_has_buffers() since that might not
be available.  Use PagePrivate() instead since that's more general.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:31:20 +02:00
David Howells
0d67a46df0 [PATCH] BLOCK: Remove duplicate declaration of exit_io_context() [try #6]
Remove the duplicate declaration of exit_io_context() from linux/sched.h.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:31:20 +02:00
David Howells
cf9a2ae8d4 [PATCH] BLOCK: Move functions out of buffer code [try #6]
Move some functions out of the buffering code that aren't strictly buffering
specific.  This is a precursor to being able to disable the block layer.

 (*) Moved some stuff out of fs/buffer.c:

     (*) The file sync and general sync stuff moved to fs/sync.c.

     (*) The superblock sync stuff moved to fs/super.c.

     (*) do_invalidatepage() moved to mm/truncate.c.

     (*) try_to_release_page() moved to mm/filemap.c.

 (*) Moved some related declarations between header files:

     (*) declarations for do_invalidatepage() and try_to_release_page() moved
     	 to linux/mm.h.

     (*) __set_page_dirty_buffers() moved to linux/buffer_head.h.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:31:19 +02:00
Martin Peschke
4090959aee [PATCH] blktrace: cleanup using on_each_cpu
This patch kills a few lines of code in blktrace by making use of
on_each_cpu().

Signed-off-by: Martin Peschke <mp3@de.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:31:19 +02:00
Oleg Nesterov
cf342e52e3 [PATCH] Don't need to disable interrupts for tasklist_lock
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:31:18 +02:00
Oleg Nesterov
25034d7a83 [PATCH] exit_io_context: don't disable irqs
We don't need to disable irqs to clear current->io_context, it is protected
by ->alloc_lock. Even IF it was possible to submit I/O from IRQ on behalf of
current this irq_disable() can't help: current_io_context() will re-instantiate
->io_context after irq_enable().

We don't need task_lock() or local_irq_disable() to clear ioc->task. This can't
prevent other CPUs from playing with our io_context anyway.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:31:18 +02:00
Jens Axboe
9bf09c2385 [PATCH] SCSI: scsi_done_q is unused
It is a leftover from before the softirq completion was migrated
to the block layer.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:31:11 +02:00
Linus Torvalds
e823aff2d6 Merge branch 'drm-patches' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6
* 'drm-patches' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (36 commits)
  drm: Use register writes instead of BITBLT_MULTI packets for buffer swap blits
  drm: use radeon specific names for radeon flags
  drm: add device/vendor id to drm_device_t for compat with FreeBSD drivers
  drm: allow multiple addMaps with the same 32-bit map offsset.
  drm: fd.o Bug #7595: Avoid u32 overflows in radeon_check_and_fixup_offset().
  drm: Fix hashtab implementation leaking illegal error codes to user space.
  drm: domain changes broke ppc r200
  drm: fixup setversion return codes..
  drm: fixup i915 error codes
  drm: realign sosme radeon code with drm git tree
  drm: realign via driver with drm git tree
  drm: remove hash tables on drm exit
  drm: cleanups
  drm: i810_dma.c: fix pointer arithmetic for 64-bit target
  drm: avoid kernel oops in some error paths calling drm_lastclose
  drm: allow detection of new VIA chipsets
  drm: fix i965 build bug
  drm: remove FALSE/TRUE that snuck in with simple memory manager changes.
  drm: Add support for Intel i965G chipsets.
  drm: add better explanation for i830/i915
  ...
2006-09-30 11:29:54 -07:00
Jens Axboe
7457e6e2d7 [PATCH] blktrace: support for logging metadata reads
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:43 +02:00
Jens Axboe
374f84ac39 [PATCH] cfq-iosched: use metadata read flag
Give meta data reads preference over regular reads, as the process
often needs to get that out of the way to do the io it was actually
interested in.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:43 +02:00
Jens Axboe
caa38fb0f4 [PATCH] ext3: make meta data reads use READ_META
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:42 +02:00
Jens Axboe
5404bc7a87 [PATCH] Allow file systems to differentiate between data and meta reads
We can use this information for making more intelligent priority
decisions, and it will also be useful for blktrace.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:42 +02:00
Jens Axboe
da20a20f3b [PATCH] ll_rw_blk: allow more flexibility for read_ahead_kb store
It can make sense to set read-ahead larger than a single request.
We should not be enforcing such policy on the user. Additionally,
using the BLKRASET ioctl doesn't impose such a restriction. So
additionally we now expose identical behaviour through the two.

Issue also reported by Anton <cbou@mail.ru>

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:41 +02:00
Jens Axboe
bf57225670 [PATCH] cfq-iosched: improve queue preemption
Don't touch the current queues, just make sure that the wanted queue
is selected next. Simplifies the logic.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:41 +02:00
Jens Axboe
dc72ef4ae3 [PATCH] Add blk_start_queueing() helper
CFQ implements this on its own now, but it's really block layer
knowledge. Tells a device queue to start dispatching requests to
the driver, taking care to unplug if needed. Also fixes the issue
where as/cfq will invoke a stopped queue, which we really don't
want.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:40 +02:00
Jens Axboe
981a79730d [PATCH] cfq-iosched: kill the empty_list
No point in having a place holder list just for empty queues, so remove
it. It's not used for anything other than to keep ->cfq_list busy.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:40 +02:00
Jens Axboe
53b03744e5 [PATCH] cfq-iosched: Kill O(N) runtime of cfq_resort_rr_list()
Currently it scales with number of processes in that priority group,
which is potentially not very nice as it's called quite often.
Basically we always need to do tail inserts, except for the case of a
new process. So just mark/detect a queue as such.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:39 +02:00
Jens Axboe
b5deef9012 [PATCH] Make sure all block/io scheduler setups are node aware
Some were kmalloc_node(), some were still kmalloc(). Change them all to
kmalloc_node().

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:39 +02:00
Jens Axboe
a3b05e8f58 [PATCH] Kill various deprecated/unused block layer defines/functions
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:38 +02:00
Jens Axboe
1ea25ecb72 [PATCH] Audit block layer inlines
Kill a few inlines that bring in too much code to more than one location
Shrinks kernel text by about 300 bytes on 32-bit x86.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:38 +02:00
Jens Axboe
4050cf1674 [PATCH] cfq-iosched: use new io context counting mechanism
It's ok if the read path is a lot more costly, as long as inc/dec is
really cheap. The inc/dec will happen for each created/freed io context,
while the reading only happens when a disk queue exits.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:37 +02:00
Jens Axboe
e4313dd423 [PATCH] as-iosched: use new io context counting mechanism
It's ok if the read path is a lot more costly, as long as inc/dec is
really cheap. The inc/dec will happen for each created/freed io context,
while the reading only happens when a disk queue exits.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:37 +02:00
Jens Axboe
4a893e837b [PATCH] elevator: define ioc counting mechanism
None of the in-kernel primitives for handling "atomic" counting seem
to be a good fit. We need something that is essentially free for
incrementing/decrementing, while the read side may be more expensive
as we only ever need to do that when a device is removed from the
kernel.

Use a per-cpu variable for maintaining a per-cpu ioc count and define
a reading mechanism that just sums up the values.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:36 +02:00
Jens Axboe
fc46379daf [PATCH] cfq-iosched: kill cfq_exit_lock
cfq_exit_lock is protecting two things now:

- The per-ioc rbtree of cfq_io_contexts

- The per-cfqd linked list of cfq_io_contexts

The per-cfqd linked list can be protected by the queue lock, as it is (by
definition) per cfqd as the queue lock is.

The per-ioc rbtree is mainly used and updated by the process itself only.
The only outside use is the io priority changing. If we move the
priority changing to not browsing the rbtree, we can remove any locking
from the rbtree updates and lookup completely. Let the sys_ioprio syscall
just mark processes as having the iopriority changed and lazily update
the private cfq io contexts the next time io is queued, and we can
remove this locking as well.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-09-30 20:29:36 +02:00