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  1. 30 Apr, 2007 6 commits
    • Jens Axboe's avatar
      cfq-iosched: sort RT queues into the rbtree · 0c534e0a
      Jens Axboe authored 
      Currently CFQ does a linked insert into the current list for RT
queues. We can just factor the class into the rb insertion,
and then we don't have to treat RT queues in a special way. It's
faster, too.
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      0c534e0a
    • Jens Axboe's avatar
      [PATCH] cfq-iosched: speed up rbtree handling · cc09e299
      Jens Axboe authored 
      For cases where the rbtree is mainly used for sorting and min retrieval,
a nice speedup of the rbtree code is to maintain a cache of the leftmost
node in the tree.

Also spotted in the CFS CPU scheduler code.

Improved by Alan D. Brunelle <Alan.Brunelle@hp.com> by updating the
leftmost hint in cfq_rb_first() if it isn't set, instead of only
updating it on insert.
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      cc09e299
    • Jens Axboe's avatar
      cfq-iosched: rework the whole round-robin list concept · d9e7620e
      Jens Axboe authored 
      Drawing on some inspiration from the CFS CPU scheduler design, overhaul
the pending cfq_queue concept list management. Currently CFQ uses a
doubly linked list per priority level for sorting and service uses.
Kill those lists and maintain an rbtree of cfq_queue's, sorted by when
to service them.

This unfortunately means that the ionice levels aren't as strong
anymore, will work on improving those later. We only scale the slice
time now, not the number of times we service. This means that latency
is better (for all priority levels), but that the distinction between
the highest and lower levels aren't as big.

The diffstat speaks for itself.

 cfq-iosched.c |  363 +++++++++++++++++---------------------------------
 1 file changed, 125 insertions(+), 238 deletions(-)
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      d9e7620e
    • Jens Axboe's avatar
      cfq-iosched: minor updates · 1afba045
      Jens Axboe authored 
      - Move the queue_new flag clear to when the queue is selected
- Only select the non-first queue in cfq_get_best_queue(), if there's
  a substantial difference between the best and first.
- Get rid of ->busy_rr
- Only select a close cooperator, if the current queue is known to take
  a while to "think".
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      1afba045
    • Jens Axboe's avatar
      cfq-iosched: development update · 6d048f53
      Jens Axboe authored 
      - Implement logic for detecting cooperating processes, so we
  choose the best available queue whenever possible.

- Improve residual slice time accounting.

- Remove dead code: we no longer see async requests coming in on
  sync queues. That part was removed a long time ago. That means
  that we can also remove the difference between cfq_cfqq_sync()
  and cfq_cfqq_class_sync(), they are now indentical. And we can
  kill the on_dispatch array, just make it a counter.

- Allow a process to go into the current list, if it hasn't been
  serviced in this scheduler tick yet.

Possible future improvements including caching the cfqq lookup
in cfq_close_cooperator(), so we don't have to look it up twice.
cfq_get_best_queue() should just use that last decision instead
of doing it again.
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      6d048f53
    • Jens Axboe's avatar
      cfq-iosched: improve preemption for cooperating tasks · 1e3335de
      Jens Axboe authored 
      When testing the syslet async io approach, I discovered that CFQ
sometimes didn't perform as well as expected. cfq_should_preempt()
needs to better check for cooperating tasks, so fix that by allowing
preemption of an equal priority queue if the recently queued request
is as good a candidate for IO as the one we are currently waiting for.
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      1e3335de
  3. 28 Apr, 2007 3 commits
    • Linus Torvalds's avatar
      Merge branch 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6 · b9099ff6
      Linus Torvalds authored 
      * 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6:
  sis900: Allocate rx replacement buffer before rx operation
  usb-net/pegasus: simplify carrier detection
      b9099ff6
    • Neil Horman's avatar
      sis900: Allocate rx replacement buffer before rx operation · dc5a1449
      Neil Horman authored 
      Just found a hole in my last patch.  It was reported to me that shortly after we
integrated this patch.  The report was of an oops that took place inside of
netif_rx when using the sis900 driver.  Looking at my origional patch I noted
that there was a spot between the new skb_alloc and the refill_rx_ring label
where skb got reassigned to the pointer currently held in the rx_ring for the
purposes of receiveing the frame.  The result of this is however that the buffer
that gets passed to netif_rx (if it is called), then gets placed right back into
the rx_ring.  So if you receive frames fast enough the skb being processed by
the network stack can get corrupted.  The reporter is testing out the fix I've
written for this below (I'm not near my hardware at the moment to test myself),
but I wanted to post it for review ASAP.  I'll post test results when I hear
them, but I think this is a pretty straightforward fix.  It just uses a separate
pointer to do the rx operation, so that we don't improperly reassign the pointer
that we use to refill the rx ring.
Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
      dc5a1449
    • Dan Williams's avatar
      usb-net/pegasus: simplify carrier detection · 1764f150
      Dan Williams authored 
      Simplify pegasus carrier detection; rely only on the periodic MII
polling.  Reverts pieces of c43c49bd.
Signed-off-by: default avatarDan Williams <dcbw@redhat.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
      1764f150
  5. 27 Apr, 2007 31 commits
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