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  1. 25 8月, 2012 3 次提交
    • B
      sfc: Simplify TSO header buffer allocation · f7251a9c
      由 Ben Hutchings 提交于 
      TSO header buffers contain a control structure immediately followed by
the packet headers, and are kept on a free list when not in use.  This
complicates buffer management and tends to result in cache read misses
when we recycle such buffers (particularly if DMA-coherent memory
requires caches to be disabled).

Replace the free list with a simple mapping by descriptor index.  We
know that there is always a payload descriptor between any two
descriptors with TSO header buffers, so we can allocate only one
such buffer for each two descriptors.

While we're at it, use a standard error code for allocation failure,
not -1.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      f7251a9c
    • B
      sfc: Stop TX queues before they fill up · 14bf718f
      由 Ben Hutchings 提交于 
      We now have a definite upper bound on the number of descriptors per
skb; use that to stop the queue when the next packet might not fit.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      14bf718f
    • B
      sfc: Refactor struct efx_tx_buffer to use a flags field · 7668ff9c
      由 Ben Hutchings 提交于 
      Add a flags field to struct efx_tx_buffer, replacing the
continuation and map_single booleans.

Since a single descriptor cannot be both a TSO header and the last
descriptor for an skb, unionise efx_tx_buffer::{skb,tsoh} and add
flags for validity of these fields.

Clear all flags in free buffers (whereas previously the continuation
flag would be set).
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      7668ff9c
  3. 02 8月, 2012 1 次提交
    • B
      sfc: Fix maximum number of TSO segments and minimum TX queue size · 7e6d06f0
      由 Ben Hutchings 提交于 
      Currently an skb requiring TSO may not fit within a minimum-size TX
queue.  The TX queue selected for the skb may stall and trigger the TX
watchdog repeatedly (since the problem skb will be retried after the
TX reset).  This issue is designated as CVE-2012-3412.

Set the maximum number of TSO segments for our devices to 100.  This
should make no difference to behaviour unless the actual MSS is less
than about 700.  Increase the minimum TX queue size accordingly to
allow for 2 worst-case skbs, so that there will definitely be space
to add an skb after we wake a queue.

To avoid invalidating existing configurations, change
efx_ethtool_set_ringparam() to fix up values that are too small rather
than returning -EINVAL.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7e6d06f0
  5. 17 7月, 2012 3 次提交
  7. 23 2月, 2012 1 次提交
  9. 14 2月, 2012 1 次提交
  11. 27 1月, 2012 1 次提交
  13. 04 12月, 2011 1 次提交
  15. 01 12月, 2011 1 次提交
  17. 30 11月, 2011 1 次提交
  19. 19 10月, 2011 1 次提交
  21. 07 10月, 2011 1 次提交
  23. 23 9月, 2011 1 次提交
  25. 11 8月, 2011 1 次提交
  27. 17 5月, 2011 1 次提交
    • B
      sfc: Use netif_device_{detach,attach}() around reset and self-test · e4abce85
      由 Ben Hutchings 提交于 
      We need to keep the TX queues stopped throughout a reset, without
triggering the TX watchdog and regardless of the link state.  The
proper way to do this is to use netif_device_{detach,attach}() just as
we do around suspend/resume, rather than the current bodge of faking
link-down.

Since we also need to do this during an offline self-test and we
perform a reset during that, add these function calls outside of
efx_reset_down() and efx_reset_up().
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      e4abce85
  29. 12 4月, 2011 1 次提交
  31. 01 3月, 2011 1 次提交
  33. 16 2月, 2011 2 次提交
    • B
      sfc: Add TX queues for high-priority traffic · 94b274bf
      由 Ben Hutchings 提交于 
      Implement the ndo_setup_tc() operation with 2 traffic classes.

Current Solarstorm controllers do not implement TX queue priority, but
they do allow queues to be 'paced' with an enforced delay between
packets.  Paced and unpaced queues are scheduled in round-robin within
two separate hardware bins (paced queues with a large delay may be
placed into a third bin temporarily, but we won't use that).  If there
are queues in both bins, the TX scheduler will alternate between them.

If we make high-priority queues unpaced and best-effort queues paced,
and high-priority queues are mostly empty, a single high-priority queue
can then instantly take 50% of the packet rate regardless of how many
of the best-effort queues have descriptors outstanding.

We do not actually want an enforced delay between packets on best-
effort queues, so we set the pace value to a reserved value that
actually results in a delay of 0.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      94b274bf
    • B
      sfc: Move TX queue core queue mapping into tx.c · 60031fcc
      由 Ben Hutchings 提交于 
      efx_hard_start_xmit() needs to implement a mapping which is the
inverse of tx_queue::core_txq.  Move the initialisation of
tx_queue::core_txq next to efx_hard_start_xmit() to make the
connection more obvious.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      60031fcc
  35. 11 12月, 2010 1 次提交
    • B
      sfc: Remove ancient support for nesting of TX stop · c04bfc6b
      由 Ben Hutchings 提交于 
      Long before this driver went into mainline, it had support for
multiple TX queues per port, with lockless TX enabled.  Since Linux
did not know anything of this, filling up any hardware TX queue would
stop the core TX queue and multiple hardware TX queues could fill up
before the scheduler reacted.  Thus it was necessary to keep a count
of how many TX queues were stopped and to wake the core TX queue only
when all had free space again.

The driver also previously (ab)used the per-hardware-queue stopped
flag as a counter to deal with various things that can inhibit TX, but
it no longer does that.

Remove the per-channel tx_stop_count, tx_stop_lock and
per-hardware-queue stopped count and just use the networking core
queue state directly.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      c04bfc6b
  37. 07 12月, 2010 2 次提交
    • B
      sfc: Use TX push whenever adding descriptors to an empty queue · cd38557d
      由 Ben Hutchings 提交于 
      Whenever we add DMA descriptors to a TX ring and update the ring
pointer, the TX DMA engine must first read the new DMA descriptors and
then start reading packet data.  However, all released Solarflare 10G
controllers have a 'TX push' feature that allows us to reduce latency
by writing the first new DMA descriptor along with the pointer update.
This is only useful when the queue is empty.  The hardware should
ignore the pushed descriptor if the queue is not empty, but this check
is buggy, so we must do it in software.

In order to tell whether a TX queue is empty, we need to compare the
previous transmission count (write_count) and completion count
(read_count).  However, if we do that every time we update the ring
pointer then read_count may ping-pong between the caches of two CPUs
running the transmission and completion paths for the queue.
Therefore, we split the check for an empty queue between the
completion path and the transmission path:

- Add an empty_read_count field representing a point at which the
  completion path saw the TX queue as empty.
- Add an old_write_count field for use on the completion path.
- On the completion path, whenever read_count reaches or passes
  old_write_count the TX queue may be empty.  We then read
  write_count, set empty_read_count if read_count == write_count,
  and update old_write_count.
- On the transmission path, we read empty_read_count.  If it's set, we
  compare it with the value of write_count before the current set of
  descriptors was added.  If they match, the queue really is empty and
  we can use TX push.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      cd38557d
    • B
      sfc: Use ACCESS_ONCE when copying efx_tx_queue::read_count · 51c56f40
      由 Ben Hutchings 提交于 
      Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      51c56f40
  39. 04 12月, 2010 1 次提交
  41. 11 9月, 2010 2 次提交
  43. 25 6月, 2010 1 次提交
  45. 29 4月, 2010 1 次提交
  47. 30 3月, 2010 1 次提交
    • T
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      由 Tejun Heo 提交于 
      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: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  49. 24 12月, 2009 1 次提交
  51. 30 11月, 2009 4 次提交
  53. 25 11月, 2009 3 次提交
  55. 24 10月, 2009 1 次提交