1. 10 Oct, 2012 1 commit
  2. 21 May, 2012 2 commits
  3. 09 Apr, 2012 1 commit
  4. 30 Mar, 2010 1 commit
    • Tejun Heo's avatar
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo authored
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      
        http://userweb.kernel.org/~tj/misc/slabh-sweep.py
      
      The script does the followings.
      
      * Scan files for gfp and slab usages and update includes such that
        only the necessary includes are there.  ie. if only gfp is used,
        gfp.h, if slab is used, slab.h.
      
      * When the script inserts a new include, it looks at the include
        blocks and try to put the new include such that its order conforms
        to its surrounding.  It's put in the include block which contains
        core kernel includes, in the same order that the rest are ordered -
        alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
        doesn't seem to be any matching order.
      
      * If the script can't find a place to put a new include (mostly
        because the file doesn't have fitting include block), it prints out
        an error message indicating which .h file needs to be added to the
        file.
      
      The conversion was done in the following steps.
      
      1. The initial automatic conversion of all .c files updated slightly
         over 4000 files, deleting around 700 includes and adding ~480 gfp.h
         and ~3000 slab.h inclusions.  The script emitted errors for ~400
         files.
      
      2. Each error was manually checked.  Some didn't need the inclusion,
         some needed manual addition while adding it to implementation .h or
         embedding .c file was more appropriate for others.  This step added
         inclusions to around 150 files.
      
      3. The script was run again and the output was compared to the edits
         from #2 to make sure no file was left behind.
      
      4. Several build tests were done and a couple of problems were fixed.
         e.g. lib/decompress_*.c used malloc/free() wrappers around slab
         APIs requiring slab.h to be added manually.
      
      5. The script was run on all .h files but without automatically
         editing them as sprinkling gfp.h and slab.h inclusions around .h
         files could easily lead to inclusion dependency hell.  Most gfp.h
         inclusion directives were ignored as stuff from gfp.h was usually
         wildly available and often used in preprocessor macros.  Each
         slab.h inclusion directive was examined and added manually as
         necessary.
      
      6. percpu.h was updated not to include slab.h.
      
      7. Build test were done on the following configurations and failures
         were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
         distributed build env didn't work with gcov compiles) and a few
         more options had to be turned off depending on archs to make things
         build (like ipr on powerpc/64 which failed due to missing writeq).
      
         * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
         * powerpc and powerpc64 SMP allmodconfig
         * sparc and sparc64 SMP allmodconfig
         * ia64 SMP allmodconfig
         * s390 SMP allmodconfig
         * alpha SMP allmodconfig
         * um on x86_64 SMP allmodconfig
      
      8. percpu.h modifications were reverted so that it could be applied as
         a separate patch and serve as bisection point.
      
      Given the fact that I had only a couple of failures from tests on step
      6, I'm fairly confident about the coverage of this conversion patch.
      If there is a breakage, it's likely to be something in one of the arch
      headers which should be easily discoverable easily on most builds of
      the specific arch.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Guess-its-ok-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  5. 15 Jun, 2009 1 commit
  6. 30 Mar, 2009 1 commit
  7. 13 Jul, 2007 2 commits
    • Dan Williams's avatar
      async_tx: add the async_tx api · 9bc89cd8
      Dan Williams authored
      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: default avatarDan Williams <dan.j.williams@intel.com>
      Acked-By: default avatarNeilBrown <neilb@suse.de>
      9bc89cd8
    • Dan Williams's avatar
      xor: make 'xor_blocks' a library routine for use with async_tx · 685784aa
      Dan Williams authored
      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: default avatarDan Williams <dan.j.williams@intel.com>
      685784aa
  8. 16 Apr, 2005 1 commit
    • Linus Torvalds's avatar
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds authored
      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