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  1. 12 10月, 2008 2 次提交
  3. 15 7月, 2008 1 次提交
  5. 05 6月, 2008 2 次提交
  7. 08 2月, 2008 1 次提交
  9. 21 12月, 2007 1 次提交
  11. 20 10月, 2007 2 次提交
  13. 25 8月, 2007 1 次提交
  15. 18 7月, 2007 1 次提交
  17. 13 7月, 2007 3 次提交
    • D
      async_tx: add the async_tx api · 9bc89cd8
      由 Dan Williams 提交于 
      The async_tx api provides methods for describing a chain of asynchronous
bulk memory transfers/transforms with support for inter-transactional
dependencies.  It is implemented as a dmaengine client that smooths over
the details of different hardware offload engine implementations.  Code
that is written to the api can optimize for asynchronous operation and the
api will fit the chain of operations to the available offload resources. 
 
	I imagine that any piece of ADMA hardware would register with the
	'async_*' subsystem, and a call to async_X would be routed as
	appropriate, or be run in-line. - Neil Brown

async_tx exploits the capabilities of struct dma_async_tx_descriptor to
provide an api of the following general format:

struct dma_async_tx_descriptor *
async_<operation>(..., struct dma_async_tx_descriptor *depend_tx,
			dma_async_tx_callback cb_fn, void *cb_param)
{
	struct dma_chan *chan = async_tx_find_channel(depend_tx, <operation>);
	struct dma_device *device = chan ? chan->device : NULL;
	int int_en = cb_fn ? 1 : 0;
	struct dma_async_tx_descriptor *tx = device ?
		device->device_prep_dma_<operation>(chan, len, int_en) : NULL;

	if (tx) { /* run <operation> asynchronously */
		...
		tx->tx_set_dest(addr, tx, index);
		...
		tx->tx_set_src(addr, tx, index);
		...
		async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
	} else { /* run <operation> synchronously */
		...
		<operation>
		...
		async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
	}

	return tx;
}

async_tx_find_channel() returns a capable channel from its pool.  The
channel pool is organized as a per-cpu array of channel pointers.  The
async_tx_rebalance() routine is tasked with managing these arrays.  In the
uniprocessor case async_tx_rebalance() tries to spread responsibility
evenly over channels of similar capabilities.  For example if there are two
copy+xor channels, one will handle copy operations and the other will
handle xor.  In the SMP case async_tx_rebalance() attempts to spread the
operations evenly over the cpus, e.g. cpu0 gets copy channel0 and xor
channel0 while cpu1 gets copy channel 1 and xor channel 1.  When a
dependency is specified async_tx_find_channel defaults to keeping the
operation on the same channel.  A xor->copy->xor chain will stay on one
channel if it supports both operation types, otherwise the transaction will
transition between a copy and a xor resource.

Currently the raid5 implementation in the MD raid456 driver has been
converted to the async_tx api.  A driver for the offload engines on the
Intel Xscale series of I/O processors, iop-adma, is provided in a later
commit.  With the iop-adma driver and async_tx, raid456 is able to offload
copy, xor, and xor-zero-sum operations to hardware engines.
 
On iop342 tiobench showed higher throughput for sequential writes (20 - 30%
improvement) and sequential reads to a degraded array (40 - 55%
improvement).  For the other cases performance was roughly equal, +/- a few
percentage points.  On a x86-smp platform the performance of the async_tx
implementation (in synchronous mode) was also +/- a few percentage points
of the original implementation.  According to 'top' on iop342 CPU
utilization drops from ~50% to ~15% during a 'resync' while the speed
according to /proc/mdstat doubles from ~25 MB/s to ~50 MB/s.
 
The tiobench command line used for testing was: tiobench --size 2048
--block 4096 --block 131072 --dir /mnt/raid --numruns 5
* iop342 had 1GB of memory available

Details:
* if CONFIG_DMA_ENGINE=n the asynchronous path is compiled away by making
  async_tx_find_channel a static inline routine that always returns NULL
* when a callback is specified for a given transaction an interrupt will
  fire at operation completion time and the callback will occur in a
  tasklet.  if the the channel does not support interrupts then a live
  polling wait will be performed
* the api is written as a dmaengine client that requests all available
  channels
* In support of dependencies the api implicitly schedules channel-switch
  interrupts.  The interrupt triggers the cleanup tasklet which causes
  pending operations to be scheduled on the next channel
* Xor engines treat an xor destination address differently than a software
  xor routine.  To the software routine the destination address is an implied
  source, whereas engines treat it as a write-only destination.  This patch
  modifies the xor_blocks routine to take a an explicit destination address
  to mirror the hardware.

Changelog:
* fixed a leftover debug print
* don't allow callbacks in async_interrupt_cond
* fixed xor_block changes
* fixed usage of ASYNC_TX_XOR_DROP_DEST
* drop dma mapping methods, suggested by Chris Leech
* printk warning fixups from Andrew Morton
* don't use inline in C files, Adrian Bunk
* select the API when MD is enabled
* BUG_ON xor source counts <= 1
* implicitly handle hardware concerns like channel switching and
  interrupts, Neil Brown
* remove the per operation type list, and distribute operation capabilities
  evenly amongst the available channels
* simplify async_tx_find_channel to optimize the fast path
* introduce the channel_table_initialized flag to prevent early calls to
  the api
* reorganize the code to mimic crypto
* include mm.h as not all archs include it in dma-mapping.h
* make the Kconfig options non-user visible, Adrian Bunk
* move async_tx under crypto since it is meant as 'core' functionality, and
  the two may share algorithms in the future
* move large inline functions into c files
* checkpatch.pl fixes
* gpl v2 only correction

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-By: NNeilBrown <neilb@suse.de>
      9bc89cd8
    • D
      xor: make 'xor_blocks' a library routine for use with async_tx · 685784aa
      由 Dan Williams 提交于 
      The async_tx api tries to use a dma engine for an operation, but will fall
back to an optimized software routine otherwise.  Xor support is
implemented using the raid5 xor routines.  For organizational purposes this
routine is moved to a common area.

The following fixes are also made:
* rename xor_block => xor_blocks, suggested by Adrian Bunk
* ensure that xor.o initializes before md.o in the built-in case
* checkpatch.pl fixes
* mark calibrate_xor_blocks __init, Adrian Bunk

Cc: Adrian Bunk <bunk@stusta.de>
Cc: NeilBrown <neilb@suse.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
      685784aa
    • C
      dm mpath: rdac · dd172d72
      由 Chandra Seetharaman 提交于 
      This patch supports LSI/Engenio devices in RDAC mode. Like dm-emc
it requires userspace support. In your multipath.conf file you must have:

path_checker            rdac
hardware_handler        "1 rdac"
prio_callout		"/sbin/mpath_prio_tpc /dev/%n"

And you also then must have a updated multipath tools release which
has rdac support.
Signed-off-by: NChandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      dd172d72
  19. 10 5月, 2007 1 次提交
  21. 11 12月, 2006 1 次提交
  23. 03 10月, 2006 2 次提交
  25. 01 10月, 2006 1 次提交
    • D
      [PATCH] BLOCK: Make it possible to disable the block layer [try #6] · 9361401e
      由 David Howells 提交于 
      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: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      9361401e
  27. 27 6月, 2006 3 次提交
  29. 11 4月, 2006 1 次提交
    • N
      [PATCH] md: make sure 64bit fields in version-1 metadata are 64-bit aligned · 6f91fe88
      由 NeilBrown 提交于 
      reshape_position is a 64bit field that was not 64bit aligned.  So swap with
new_level.

NOTE: this is a user-visible change.  However:
  - The bad code has not appeared in a released kernel
  - This code is still marked 'experimental'
  - This only affects version-1 superblock, which are not in wide use
  - These field are only used (rather than simply reported) by user-space
    tools in extemely rare circumstances : after a reshape crashes in the
    first second of the reshape process.

So I believe that, at this stage, the change is safe.  Especially if people
heed the 'help' message on use mdadm-2.4.1.
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      6f91fe88
  31. 28 3月, 2006 1 次提交
  33. 17 4月, 2005 1 次提交
    • L
      Linux-2.6.12-rc2 · 1da177e4
      由 Linus Torvalds 提交于 
      Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
      1da177e4